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Cyclones in the Pacific
Title Cyclones in the Pacific
Description This colorful image superimposes measurements of wind direction on top of wind speed. NASA's microwave scatterometer, QuickSCAT, collected the image on February 15, 2005, over the South Pacific where two large cyclones are moving steadily closer to one another in a potentially dangerous dance. It is very unusual for cyclones to be so close together in the South Pacific, and it's hard to predict how the storms will interact. One possibility is that the weaker storm will be tugged off course by the large-scale atmospheric circulation of the other. Eventually the weaker storm will seem to "orbit" the stronger storm. The second possibility is that the outflow from one storm will impede the outflow from the other storm, weakening the second storm. Regardless of the interaction, the storms pose a potentially deadly threat to American Samoa and the Cook Islands, which are shown as small grey dots. At the time this image was acquired, Olaf was a strengthening Category 4 cyclone, with steady winds of 135 knots and gusts up to 165 knots. Nancy was beginning to weaken with winds of 85 knots and gusts of 115 knots. The strongest winds, shown in pink, circle the center of the storms. Even without any sort of interaction, the two large storms could pack a dangerous one-two punch to the island nations of the South Pacific. NASA image courtesy Timothy Liu, Wendy Tang, and Xiaosu Xie, of the QuikSCAT Science Team at the Jet Propulsion Laboratory.
Cyclones in the Pacific
Title Cyclones in the Pacific
Description The SeaWinds scatterometer aboard NASA?s QuikSCAT satellite collected the data used to create this colorful image of Cyclone Olaf churing in the South Pacific on February 16, 2005. The colored background shows the near-surface wind speeds at 2.5-kilometer resolution. The strongest winds, shown in purple, are at the center of the storm, with gradually weakening winds forming rings around the center. The black barbs indicate wind speed and direction at QuikSCAT?s nominal, 25-kilometer resolution, white barbs indicate areas of heavy rain. NASA?s Quick Scatterometer (QuikSCAT) spacecraft was launched from Vandenberg Air Force Base, California, on June 19, 1999. QuikScat carries the SeaWinds scatterometer, a specialized microwave radar that measures near-surface wind speed and direction under all weather and cloud conditions over the Earth?s oceans. NASA image courtesy of the QuikSCAT Science Team at the Jet Propulsion Laboratory.
Cyclones in the Pacific
Title Cyclones in the Pacific
Description The SeaWinds scatterometer aboard NASA?s QuikSCAT satellite collected the data used to create this colorful image of Cyclone Olaf churing in the South Pacific on February 16, 2005. The colored background shows the near-surface wind speeds at 2.5-kilometer resolution. The strongest winds, shown in purple, are at the center of the storm, with gradually weakening winds forming rings around the center. The black barbs indicate wind speed and direction at QuikSCAT?s nominal, 25-kilometer resolution, white barbs indicate areas of heavy rain. NASA?s Quick Scatterometer (QuikSCAT) spacecraft was launched from Vandenberg Air Force Base, California, on June 19, 1999. QuikScat carries the SeaWinds scatterometer, a specialized microwave radar that measures near-surface wind speed and direction under all weather and cloud conditions over the Earth?s oceans. NASA image courtesy of the QuikSCAT Science Team at the Jet Propulsion Laboratory.
Hurricane Dean
Title Hurricane Dean
Description Hurricane Dean was the first hurricane of the 2007 Atlantic Hurricane Season. The storm system formed off the coast of South America on August 13. It traveled west, building strength from the warm waters as it headed towards the South American coast and the southern arc of the Caribbean Islands. By August 17, it had grown in power to become a Category 3 hurricane, [ http://www.nhc.noaa.gov/aboutsshs.shtml ] and forecasters were calling for it to potentially gain yet more strength as it passed over the warm waters of the Caribbean Sea. Dean was projected to cause major damage. Mexican authorities, according to news sources, were warning residents in the Yucatan Peninsula of the danger of the coming storm, which was projected to strike the peninsula. The storm might also brush against the islands of Hispaniola, Jamaica, and Cuba among others. Some forecasters were concerned about the possibility of Dean developing into super storm in the Gulf of Mexico, where storm surge and waves as well as winds might pose significant dangers to the oil and gas platforms. This data visualization of the hurricane shows observations from the QuikSCAT satellite on August 16, 2007, at 6:55 p.m. local time (21:55 UTC). At this time, Dean was poised to cross the Windward Islands of the Caribbean, while grazing the coast of Venezuela on the South American mainland. Peak winds were around 160 kilometers per hour (100 miles per hour, 85 knots) at this time, according to Unisys Weather's Hurricane information page, [ http://weather.unisys.com/hurricane/ ] making Dean a Category 2 hurricane. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. QuikSCAT measurements of the wind strength of Hurricane Dean and other tropical cyclones can be slower than actual wind speeds. QuikSCAT's scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction. To relate the radar signal to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to exact wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Hurricane Dean
Title Hurricane Dean
Description Dean may have been the first Atlantic hurricane of the 2007 season, but days after first forming, it was also classified among the strongest hurricanes recorded. Dean became a Category 5 hurricane [ http://www.nhc.noaa.gov/aboutsshs.shtml ] before coming ashore on Mexico's Yucatan Peninsula on August 21. Dean began as a wave-like disturbance in the cloud bands off South America, which gathered together to form a storm system on August 13. Fueled by the deep warm waters of the Caribbean, Dean quickly grew into a major hurricane, reaching its peak just before coming ashore. As it traveled across the Caribbean, the storm also caused great damage to Jamaica, Grand Cayman Island, and other Caribbean islands. This data visualization of the hurricane shows observations from the QuikSCAT satellite on August 20, 2007, at 5:31 p.m. local time (23:31 UTC). At this time, Dean was in the Gulf of Mexico between Cuba, Jamaica, and the Central American peninsula heading towards the Yucatan Peninsula. Peak winds were around 250 kilometers per hour (155 miles per hour, 135 knots) at this time, according to Unisys Weather's Hurricane information page. [ http://weather.unisys.com/hurricane/ ] With these wind speeds, Dean just reached Category 5 status. The image depicts wind speed in color and wind direction with small barbs. The highest wind speeds, shown in purple, surround the center of the storm. The strongest winds on the north side of the eyewall are depicted in pink. Areas of heavy rain, shown with white barbs, correspond with stronger winds. QuikSCAT measurements of the wind strength of Dean and other tropical cyclones can be slower than actual wind speeds. QuikSCAT's scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction. To relate the radar signal to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to exact wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Hurricane Dean
Title Hurricane Dean
Description QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory., The 2007 Atlantic hurricane season had three named storms, but no hurricanes until the middle of August, when Tropical Storm Dean formed. By August 20, when the QuikSCAT satellite captured the data used to make this image, Dean was an extremely powerful Category 4 [ http://www.nhc.noaa.gov/aboutsshs.shtml ] hurricane. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The center of the storm is dominated by purple, indicating high wind speeds. Pale pink circles the eye where winds were off the scale. Dark red and orange areas spread some distance from the eye: Dean was a large and powerful storm. Dean began as a wave-like disturbance in the cloud bands off South America, which gathered together to form a storm system on August 13. By August 18, Dean had grown in power to become a Category 4 hurricane, [ http://www.nhc.noaa.gov/aboutsshs.shtml ] swirling in the Caribbean Sea. The storm caused great damage to Jamaica and Grand Cayman Island, among other Caribbean islands, and as of August 19, it was forecast to come ashore on the Mexican Yucatan Peninsula not far from the border with Belize. Forecasters at the National Hurricane Center [ http://www.nhc.noaa.gov/index.shtml? ] were also expecting the storm to continue to gather power to Category Five strength. When QuikSCAT measured the storm on August 20, 2007, at 8:04 a.m. local time (14:04 UTC), Dean was in the Gulf of Mexico between Cuba, Jamaica, and the Central American peninsula heading towards the Yucatan Peninsula. Peak winds were around 240 kilometers per hour (150 miles per hour, 130 knots) at this time, according to Unisys Weather's Hurricane information, [ http://weather.unisys.com/hurricane/ ] making Dean a powerful Category Four hurricane. QuikSCAT measurements of the wind strength of Dean and other tropical cyclones can be slower than actual wind speeds. QuikSCAT's scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction. To relate the radar signal to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to exact wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the
Hurricane Emily
Title Hurricane Emily
Description Hurricane Emily is gradually building power in the southern Caribbean. This image shows the storm's swirling wind patterns as observed by NASA's QuickScat satellite on July 13, 2005. The image depicts wind speed in color and wind direction with small barbs. The highest wind speeds, shown in purple, are on the trailing side of the developing hurricane spiral pattern. Measurements of the wind strength of Hurricane Emily show sustained winds of around 80 knots and gusts up to 100 knots. The images, however, reveal lower wind speeds. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones, however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists don't have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 kilometers per hour or 58 miles per hour). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy the QuickScat Science Team [ http://winds.jpl.nasa.gov/ ] at the Jet Propulsion Laboratory
Hurricane Emily
Title Hurricane Emily
Description When NASA's Quick Scatterometer (QuickScat) captured this image on July 13, 2005, Emily was just a few hours away from becoming a hurricane. The tropical storm was approaching Trinidad with winds of 95 kilometers per hour (60 miles per hour or 50 knots) when this image was taken at 5:05 p.m. Eastern Daylight Savings Time (21:05 UTC). The image reveals the structure of the storm, with wind speed shown in color and direction indicated by barbs. The white barbs indicate regions of heavy rain. Both the heaviest downpours and the strongest winds, shown in purple, are just east of the center of the storm. Compared to an image taken in the morning of July 13, [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12962 ] this powerful section of the storm has expanded and moved closer to the center as Emily developed through the day. Emily is the fifth tropical storm of the 2005 Atlantic hurricane season, and the second storm to reach hurricane status. By July 15, Emily reached Category 3 status on the Saffir-Simpson scale with winds of 205 km/hr (125 mph). NASA image courtesy the QuickScat Science Team [ http://winds.jpl.nasa.gov/ ] at the Jet Propulsion Laboratory.
Hurricane Frances
Title Hurricane Frances
Description The SeaWinds scatterometer aboard NASA?s QuikSCAT satellite collected the data used to create this colorful image of hurricane Frances as it approached Cuba on September 1, 2004, at 6:09 p.m. EDT. The colored background shows the near-surface wind speeds at 2.5 km resolution. The strongest winds, shown in purple, are at the center of the storm, with gradually weakening winds forming rings around the center. The black barbs indicate wind speed and direction at QuikSCAT's nominal 25 km resolution, white barbs indicate areas of heavy rain. The black grid over the image show degrees of latitude and longitude. The vertical lines of longitude start at 77 West on the left and run to 65 on the right. The horizontal lines of latitude start at 18 North on the bottom and run to 27 North on top. NASA's Quick Scatterometer (QuikSCAT [ http://winds.jpl.nasa.gov ]) spacecraft was launched from Vandenberg Air Force Base, California on June 19, 1999. QuikScat carries the SeaWinds scatterometer, a specialized microwave radar that measures near-surface wind speed and direction under all weather and cloud conditions over the Earth's oceans. In recent years, the ability to detect and track severe storms has been dramatically enhanced by the advent of weather satellites. Data from the SeaWinds scatterometer is augmenting traditional satellite images of clouds by providing direct measurements of surface winds to compare with the observed cloud patterns in an effort to better determine a hurricane's location, direction, structure, and strength. Specifically, these wind data are helping meteorologists to more accurately identify the extent of gale-force winds associated with a storm, while supplying inputs to numerical models that provide advanced warning of high waves and flooding. NASA image courtesy the QuikSCAT [ http://winds.jpl.nasa.gov ] team at NASA's Jet Propulsion Laboratory.
Hurricane Henriette
Title Hurricane Henriette
Description The 2007 eastern Pacific hurricane season had been relatively quiet when Hurricane Henriette formed in late August. Henriette was the first hurricane of the season to make landfall in that basin, skirting the Mexican coastline as it developed between August 30 and September 4, 2007. The National Hurricane Center [ http://www.nhc.noaa.gov/ ] predicted that the storm would come ashore over Baja California on September 4 as a strengthening Category 1 hurricane before traveling north through Mexico and into the United States. This data visualization of the storm shows observations from the QuikSCAT satellite on September 4, 2007, at 6:57 a.m, local time (12:57 UTC) just as Henriette was starting to come ashore on the southern tip of the Baja California peninsula. At this time, Henriette was a Category 1 [ http://www.nhc.noaa.gov/aboutsshs.shtml ] hurricane with peak winds around 110 km/hr (65 mph, 65 knots), matching predictions from the National Hurricane Center. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. QuikSCAT measurements of the wind strength of Hurricane Henriette and other tropical cyclones can be slower than actual wind speeds. QuikSCAT's scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction. To relate the radar signal to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to exact wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Hurricane Howard
Title Hurricane Howard
Description The SeaWinds scatterometer aboard NASA?s QuikSCAT satellite collected the data used to create this multicolored image of hurricane Howard off the Southern Coast of Cabo San Lucas, Mexico. This image taken on September 2nd at 4:25pm PDT, shows near-surface winds 10 meters above the ocean surface. The colored background shows the near-surface wind speeds at 2.5 km resolution, with the highest wind speeds, purple, in the center, and lower wind speeds around the outer edges of the storm. The black barbs indicate wind speed and direction at QuikSCAT's nominal 25 km resolution, white barbs indicate areas of heavy rain. The black grid marks out latitude and longitude. The vertical lines of longitude start at 120 West on the left and go to 109 West, with one line per degree. The horizontal lines of latitude start at 15 degrees North on the bottom and run to 27 degrees North, each line again indicating a single degree. NASA's Quick Scatterometer (QuikSCAT [ http://winds.jpl.nasa.gov ]) spacecraft was launched from Vandenberg Air Force Base, California on June 19, 1999. QuikScat carries the SeaWinds scatterometer, a specialized microwave radar that measures near-surface wind speed and direction under all weather and cloud conditions over the Earth's oceans. In recent years, the ability to detect and track severe storms has been dramatically enhanced by the advent of weather satellites. Data from the SeaWinds scatterometer is augmenting traditional satellite images of clouds by providing direct measurements of surface winds to compare with the observed cloud patterns in an effort to better determine a hurricane's location, direction, structure, and strength. Specifically, these wind data are helping meteorologists to more accurately identify the extent of gale-force winds associated with a storm, while supplying inputs to numerical models that provide advanced warning of high waves and flooding. NASA image courtesy the QuikSCAT [ http://winds.jpl.nasa.gov ] team at NASA's Jet Propulsion Laboratory.
Hurricane Ivan
Title Hurricane Ivan
Description With wind speeds topping 260 kilometers per hour (160 mph), Hurricane Ivan is roaring through the Caribbean as a deadly Category 5 storm. Early on September 9, 2004, the SeaWinds scatterometer aboard NASA's QuikSCAT satellite saw through Ivan's swirling clouds to measure wind speed 10 meters above the ocean surface. The result was this multi-colored image of the storm. Purple in the center of the storm shows the highest wind speeds, and green fringes around the outside of the storm show the lowest wind speeds. The black barbs indicate wind speed and direction at QuikSCAT's nominal 25 km resolution, white barbs indicate areas of heavy rain. Ivan strengthened after plowing over Grenada on Tuesday, September 7. The storm is forecast to move northwest over Jamaica and Cuba, then on to Florida. For more information, please visit the National Hurricane Center [ http://www.nhc.noaa.gov/ ]. NASA's Quick Scatterometer (QuikSCAT [ http://winds.jpl.nasa.gov ]) spacecraft was launched from Vandenberg Air Force Base, California on June 19, 1999. QuikScat carries the SeaWinds scatterometer, a specialized microwave radar that measures near-surface wind speed and direction under all weather and cloud conditions over the Earth's oceans. In recent years, the ability to detect and track severe storms has been dramatically enhanced by the advent of weather satellites. Data from the SeaWinds scatterometer is augmenting traditional satellite images of clouds by providing direct measurements of surface winds to compare with the observed cloud patterns in an effort to better determine a hurricane's location, direction, structure, and strength. Specifically, these wind data are helping meteorologists to more accurately identify the extent of gale-force winds associated with a storm, while supplying inputs to numerical models that provide advanced warning of high waves and flooding. NASA image courtesy the QuikSCAT [ http://winds.jpl.nasa.gov ] team at NASA's Jet Propulsion Laboratory.
Hurricane Javier
Title Hurricane Javier
Description The SeaWinds Scatterometer [ http://winds.jpl.nasa.gov/ ] aboard NASA's QuikSCAT satellite collected the data used to create this multicolored image of Hurricane Javier, currently nearly due south of Cabo San Lucas, Mexico. The National Hurricane Center [ http://www.nhc.noaa.gov/ ] predicts that this storm will make landfall on the western coast of Baja California sometime on September 18, 2004. This image, taken by QuikSCAT on September 16, at 6:13 p.m. PDT, shows near-surface winds 10 meters above the ocean surface. The colored background shows the near-surface wind speeds at 2.5 km resolution, with the highest wind speeds, purple, in the center, and lower wind speeds around the outer edges of the storm. The black barbs indicate wind speed and direction at QuikSCAT's nominal 25 km resolution, white barbs indicate areas of heavy rain. NASA's Quick Scatterometer (QuikSCAT) spacecraft was launched from Vandenberg Air Force Base, California on June 19, 1999. QuikScat carries the SeaWinds scatterometer, a specialized microwave radar that measures near-surface wind speed and direction under all weather and cloud conditions over the Earth's oceans. In recent years, the ability to detect and track severe storms has been dramatically enhanced by the advent of weather satellites. Data from the SeaWinds scatterometer is augmenting traditional satellite images of clouds by providing direct measurements of surface winds to compare with the observed cloud patterns in an effort to better determine a hurricane's location, direction, structure, and strength. Specifically, these wind data are helping meteorologists to more accurately identify the extent of gale-force winds associated with a storm, while supplying inputs to numerical models that provide advanced warning of high waves and flooding. NASA image courtesy of the QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] team at NASAs Jet Propulsion Laboratory.
Hurricane Katrina
Title Hurricane Katrina
Description Nearly the whole of the Gulf of Mexico was churning with the powerful winds and rains of Hurricane Katrina on August 28, 2005, when NASA's QuikSCAT [ http://winds.jpl.nasa.gov/ ] satellite captured this image. The image depicts relative wind speeds swirling around the calm center of the storm. The highest wind speeds, shown in shades of purple, circle a well-defined eye, with gradually weakening winds radiating outward. The barbs reveal wind direction, and the white barbs show heavy rainfall. At the time this image was taken, the National Hurricane Center [ http://www.nhc.noaa.gov/ ] reported that Katrina had winds of 160 miles per hour (257 kilometers per hour or 140 knots) with stronger gusts, and it was moving north-northwest at about 10 mph (16 km/hr). The storm weakened slightly before coming ashore, but was still a powerfully destructive storm. Why don't the wind speeds shown here match those reported by the National Hurricane Center? QuikSCAT measures near-surface wind speeds over the ocean based on how the winds affect the ocean. The satellite sends out high-frequency radio waves, some of which bounce off the ocean and return to the satellite. Rough, storm-tossed seas return more of the radio waves, creating a strong signal, while a mirror-smooth surface returns a weaker signal. To learn to match actual wind speeds with the type of signal that returns to the satellite, scientists compare wind measurements taken by ocean buoys to the strength of the signal received by the satellite. The more measurements scientists have, the more accurately they can correlate wind speed to the returning radar signal. Storms as large as Katrina are rare. This means that scientists have few buoy measurements to compare to the data they get from the satellite and can't match the satellite measurements to exact wind speeds. Instead, the image provides a clear picture of relative wind speeds, showing how large the strong center of the storm is and which direction winds are blowing. For official warnings and information about Hurricane Katrina, please visit the National Hurricane Center [ http://www.nhc.noaa.gov/ ]. To learn more about measuring winds from space, check out NASA's Winds [ http://winds.jpl.nasa.gov/index.cfm ] web site. NASA image courtesy the QuikSCAT Science Team at the Jet Propulsion Laboratory
Hurricane Katrina
Title Hurricane Katrina
Description Tropical Storm Katrina is shown here as observed by NASA's QuikSCAT satellite on August 25, 2005, at 08:37 UTC (4:37 a.m. in Florida). At this time, the storm had 80-kilometer-per-hour (50 miles per hour, 43 knots) sustained winds. The storm does not appear to yet have reached hurricane strength. The greater danger may be not with her winds, but with Katrina's rains. The storm is moving slowly, just 13 km/hr (8 mph), and is expected to slow as it moves over land. This means that Katrina's heavy rains will linger longer over one area, dumping 15-25 centimeters (6-10 inches) of rain over Florida and the Bahamas and possibly up to 38 cm (15 inches) in some regions, the National Hurricane Center warns. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Measurements of the wind strength of Tropical Storm Katrina show sustained winds similar to those shown by these QuikSCAT observations, though not identical. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons) and to a lesser extent, weaker storm systems like Katrina, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. For more information about the storm, please visit the National Hurricane Center [ http://www.nhc.noaa.gov/ ]. NASA image courtesy the QuikSCAT Science Team at the Jet Propulsion Laboratory
Hurricane Maria
Title Hurricane Maria
Description Hurricane Maria is shown here as observed by NASA's QuikSCAT satellite on September 6, 2005, at 09:00 UTC (4:00 a.m. Eastern Daylight Time). At this time, the hurricane had sustained winds of 165 kilometers per hour (105 miles per hour, 90 knots). The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Measurements of the wind strength of Hurricane Maria show sustained winds slightly higher than those shown by QuikSCAT observations. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy the QuikSCAT Science Team at the Jet Propulsion Laboratory
Hurricane Nate
Title Hurricane Nate
Description Hurricane Nate is shown here as observed by NASA's QuikSCAT satellite on September 7, 2005, at 10:13 UTC (6:13 a.m. Eastern Daylight Time). At this time, the hurricane had sustained winds of 110 kilometers per hour (70 miles per hour, 60 knots). These winds did not make Nate strong enough to be classified as a hurricane, but the storm crossed the threshold to hurricane status only a few hours later. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Measurements of the wind strength of Hurricane Nate show sustained winds slightly higher than those shown by QuikSCAT observations. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, and the Jet Propulsion Laboratory.
Hurricane Ophelia
Title Hurricane Ophelia
Description NASA's QuikSCAT satellite captured this image of Hurricane Ophelia on September 11, 2005, at 5:47 a.m. local time. At this time, the hurricane had sustained winds of 130 kilometers per hour (80 miles per hour, 70 knots). Ophelia has been an intriguing storm. It formed off the Florida coast (an unusual formation point for a tropical storm), gradually built power to hurricane status over the course of a few days, and then wound down in strength. After spending several days in roughly one location, Ophelia moved farther offshore, roughly parallel to the U.S. East Coast, and re-gathered strength to become the Category 1 hurricane by the time this image was taken. Forecast tracks for the storm are uncertain, but one conceivable storm track would take it ashore still at hurricane strength along the North Carolina Outer Banks shoreline. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Measurements of the wind strength of Hurricane Ophelia show sustained winds stronger than those shown by QuikSCAT observations. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, and the Jet Propulsion Laboratory.
Hurricane Paul
Title Hurricane Paul
Description As October drew to a close, Hurricane Paul was approaching the southern tip of Mexico's Baja Peninsula. The sixteenth named Pacific storm of the 2006 season, Paul was whipping up sustained winds of 165 kilometers per hour (105 miles per hour) at the time of the National Hurricane Center's 11:00 a.m. Pacific Daylight Time briefing on October 23. The storm track and intensity forecasts for Paul were still uncertain at that time, but landfall along the southern tip of Baja Peninsula as a strong storm was still a possibility. This data visualization of Hurricane Paul shows wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. The data were obtained by NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite on October 23, 2006, at 01:46 UTC (8:46 a.m. local time). Paul appears to be symmetrically shaped in this image, with wind direction barbs showing that the center of the storm has a well-defined spiral pattern around the eye. The strongest winds form a bullseye pattern around the central, calmer region of the eye of the storm. Aircraft and buoy-based measurements of the wind strength of Hurricane Paul would likely show sustained winds higher than those estimated from QuikSCAT observations. This difference is because the power of the storm makes accurate measurements from satellite difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar signal the satellite measures to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a picture of the relative wind speeds within the storm, as well as wind direction. These pieces of information can let meteorologists know where and when a storm&#8217s center of circulation has developed. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Hurricane Rita
Title Hurricane Rita
Description Hurricane Rita is shown here as observed by NASA's QuikSCAT satellite on September 20, 2005, at 10:29 UTC (6:29 a.m. Eastern Daylight Time). At this time, the hurricane had 195-kilometer-per-hour (120 mile-per-hour, 105- knot) sustained winds. Within the next 24 hours, Rita would surge in power, packing winds near 280 km/hr (175 mph, 150 knots), reaching the very top of the hurricane-strength categories and becoming the fourth most powerful storm ever recorded. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Measurements of the wind strength of Hurricane Rita show sustained winds completely off the scale shown by QuikSCAT observations. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, and the Jet Propulsion Laboratory.
Hurricane Sergio
Title Hurricane Sergio
Description For the first time since 1961, two tropical storms formed in the month of November in the Eastern Pacific. The first was Tropical Storm Rosa. On November 13, 2006, Tropical Storm Sergio became the second tropical storm of the month. Sergio, unlike Rosa, continued to build in power to reach hurricane status, making it the tenth hurricane of the 2006 Eastern Pacific storm season. While the hurricane season officially runs until the end of November, late storms are unusual. Only five other storms on record have formed later in the season than Sergio. It is also unusual for tropical storms that form this late in the season to intensify all the way to hurricane strength as Sergio did. This data visualization shows Sergio while it was a Category 2 [ http://www.nhc.noaa.gov/aboutsshs.shtml ] hurricane, early in the morning of November 16. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The data were obtained by NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite on November 16, 2006, at 12:29 UTC (5:29 a.m. local time). Sergio appears to have a well-defined and circular core, with a long apostrophe-shaped tail streaming out from the center. However, the wind-direction barbs do not spiral tightly around the center of the storm as they would in a strong hurricane. This asymmetry hints that wind shear may be pulling the storm apart. QuikSCAT employs a scatterometer, which sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. This technique does not work over land, and hence the lack of measurements over the mainland of Mexico shown here. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Hurricane Wilma
Title Hurricane Wilma
Description Tropical Storm Wilma is shown here as observed by NASA's QuikSCAT satellite on October 17, 2005, at 9:28 UTC (5:28 a.m. Eastern Daylight Time). At this time, the storm had 65-kilometer-per-hour (40-mile-per-hour, 35-knot) sustained winds. At the time of this observation, Wilma had only just become strong enough to be classified as a tropical storm and to acquire a name. Doing so, Wilma became the 21st named storm of the 2005 hurricane season. At the time of this image acquisition, Wilma was continuing to gradually build power and was projected to reach hurricane strength in the ensuing 24 hours, as winds steered the storm into the deep, warm water pool of the Gulf of Mexico. The image depicts wind speed in color and wind direction with small barbs. White barbs show to areas of heavy rain. The highest wind speeds surround the center of the storm where the developing spiral structure can be discerned. Measurements of the wind strength of Wilma from QuikSCAT may be slightly different from those measured by other means on the ground. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. However, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, and the Jet Propulsion Laboratory.
Hurricane Wilma
Title Hurricane Wilma
Description Hurricane Wilma is shown here as observed by NASA's QuikSCAT satellite on October 18, 2005, at 23:31 UTC (7:31 p.m. Eastern Daylight Time). At that time, the hurricane had sustainted winds of 130 kilometers per hour (80 miles per hour, 70 knots). However, within twelve hours of this observation, Wilma increased power quite dramatically, running the full gamut of the hurricane strength scale to Category 5 with sustained winds of 280 km/hr (175 mph, 150 knots)! At that point, Wilma became the most powerful storm in terms of both wind speeds and air pressure ever measured in an Atlantic hurricane. The image depicts wind speed in color and wind direction with small barbs. White barbs show areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Ground measurements of the wind strength of Hurricane Wilma show sustained winds somewhat higher than those shown by QuikSCAT observations. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, and the Jet Propulsion Laboratory.
Santa Ana Wind Event Over Ca …
Title Santa Ana Wind Event Over California
Description *Santa Ana Wind Event Over California* High-resolution data from NASA?s QuikScat satellite revealed the direction and intensity of the Santa Ana winds that have caused widespread fires and property damage throughout the Los Angeles Basin in the last two days. Santa Ana is an offshore and down-slope wind in Southern California that is usually channeled through mountain gaps. In this false-color image acquired at 6 a.m. PST on Jan. 6, 2003, the various arrows represent the direction of the surface winds over the ocean, with colors representing wind speed. Red arrows show winds traveling greater than 8 meters per second, orange represents 6 to 8 meters per second, white shows winds of 4 to 6 meters per second, and black represents less than 4 meters per second. (That ranges from greater than 26 feet per second to less than 13 feet per second.) Even after losing much of their strength over the ocean, the wind speed still exceeded 34 miles per hour. The wind speeds and directions are retrieved from range-compressed backscatter measured by the SeaWinds sensor aboard QuikScat. These Santa Ana winds extend more than 500 kilometers (310 miles) offshore before changing direction to flow along the shore. Useful applications of high-resolution science-quality wind products derived from range-compressed backscatter have been demonstrated in two scientific papers: one on Hurricane Floyd and the other on Catalina Eddies. This is the first demonstration of a near-real-time application. Image courtesy Timothy Liu and Hua Hu, NASA Jet Propulsion Laboratory, QuickScat [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://winds.jpl.nasa.gov/missions/quikscat/quikindex.html ] Project
Fires in Southern California
Title Fires in Southern California
Description The fires that sprang up in Southern California over the weekend of October 20, 2007, were driven by strong offshore winds, known locally as the Santa Ana Winds. The strength and scope of these winds were observed by NASA's QuikScat satellite at about 7 a.m. local time October 22. The wind speeds are shown in colors and the direction by small white barbs. The dominant direction of the winds is offshore, from the high deserts of the Great Basin southwest toward the Pacific Ocean. QuikScat measures wind speed over the ocean only, by sending radar pulses to the surface and measuring the strength of the signals returned. The strength and direction of the return signal reveal how winds are stirring the surface of the ocean. Santa Ana winds are a California firefighter's nightmare. These blustery, dry, and often hot winds blow out of the high-altitude deserts of the Great Basin and race through canyons and passes in the mountains on their way toward the coast. The air is hot not because it is bringing heat from the desert, but because it is flowing downslope from higher elevations. As fall progresses, cold air begins to sink into the Great Basin deserts to the east of California. As the air piles up at the surface, high pressure builds, and the air begins to flow downslope toward the coast. When winds blow downslope, the air gets compressed, which causes it to warm and dry out. In fact, the air can warm at a rate of 10 degrees Celsius per kilometer of descent (29 degrees Fahrenheit per mile). Canyons and passes funnel the winds, which increases their speed. Not only do the winds spread the fire, but they also dry out vegetation, making it even more flammable. NASA image courtesy the Jet Propulsion Laboratory.
Storms in the Java Sea
Title Storms in the Java Sea
Description A ferry carrying more than 600 passengers sank in the Java Sea between the islands of Borneo (image center) and Java (to the south-southwest) just before midnight on December 29, 2006, during high winds and rough seas. On January 1, 2007, a plane carrying more than 100 people crashed on its flight over the Java Sea, high winds and turbulent weather are being investigated as possible causes. The origin of surges of deadly wind in this usually relatively calm region are poorly understood, and the area is not well-monitored with traditional weather equipment. Ocean winds data from NASA's QuikScat satellite may help improve monitoring and understanding of unusual weather in the area. Data obtained from QuikScat on December 30 and January 1 shed new insights into the atmospheric conditions at the time of the tragic incidents described above. In this image from January 1, the different colors reveal different wind speeds. White arrows are wind vectors showing both direction and speed. The data from December 30 and January 1 showed that the strong winds in the Java Sea originated from the surge of a strong winter monsoon from the Asian continent. The monsoon winds blew south across the South China Sea and deflected eastward after they crossed the equator due to the rotation of Earth. The winds in the Java Sea remained strong through January 1, 2007. Associated with the eastward winds, twin cyclones were also observed by QuikScat. (A cyclone is any large-scale atmosphere circulation around a region of low air pressure. The systems spin counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.) The stronger cyclone was south of the equator (summer hemisphere) between Java and Australia, and a weaker one was north of the equator (winter hemisphere) west of Borneo. QuikScat measures ocean surface wind speed by sending radar pulses to the surface and measuring the strength of the signals that return to the sensor. The sensor's wide-scale observations make it possible for scientists to interpret local weather events, such as the recent high wind outbreak in the Java Sea region, in the context of the large-scale atmospheric circulation and to confirm connections between the two. QuikScat data are available in near-real time to operational weather forecasting agencies around the world. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, [ http://winds.jpl.nasa.gov/ ] and the Jet Propulsion Laboratory.
Super Typhoon Haitang
Title Super Typhoon Haitang
Description Typhoon Haitang is shown here churning steadily towards Taiwan and China. This image shows the storm's swirling wind patterns as observed by NASA's QuikSCAT satellite on July 14, 2005, at 19:19 UTC (14:19 Eastern Daylight Time). At this time, the typhoon was located hundreds of kilometers from the nearest major land masses. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Measurements of the wind strength of Typhoon Haitang show sustained winds of around 85 knots and gusts up to 105 knots at the time of the QuikSCAT observations. The images, however, reveal lower wind speeds. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 kilometers per hour or 58 miles per hour). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ] at the Jet Propulsion Laboratory
Super Typhoon Haitang
Title Super Typhoon Haitang
Description Typhoon Haitang is shown here as observed by NASA's QuikSCAT satellite on July 15, 2005, at 08:29 UTC (17:29 in Tokyo). At this time, the typhoon had 185 kilometer per hour (100 knots) sustained winds, giving it a Category 3 rating on the Saffir-Simpson tropical storm scale. Taiwan is located to the west of the storm, not far off the typhoon's path at the time. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Measurements of the wind strength of Typhoon Haitang show sustained winds much stronger than those shown by QuikSCAT observations. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 kilometers per hour or 58 miles per hour). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ] at the Jet Propulsion Laboratory
Super Typhoon Nabi
Title Super Typhoon Nabi
Description The calm eye of Typhoon Nabi stands out like a bulls-eye in the center of the concentric circles of color that make up the storm. The colors represent wind speed, with purple and pink showing the highest winds, while tiny barbs show the wind's direction spinning around the eye of the storm. The white barbs indicate regions of heavy rainfall. The image was created using data collected by the QuikSCAT satellite on September 1, 2005, when Nabi was growing into a powerful super typhoon with winds of 260 kilometers per hour (160 miles per hour, 140 knots) and gusts to 315 km/hr (196 mph, 170 knots). At the time this image was taken, however, Nabi had winds of about 213 km/hr (132 mph, 115 knots) with gusts to 260 km/hr (160 mph, 140 knots), making it the equivalent of a Category 3 hurricane on the Saffir-Simpson Hurricane Scale. The wind speeds shown in this image don't match the winds reported by the Joint Typhoon Warning Center. This is because QuikSCAT measures near-surface wind speeds over the ocean based on how the winds affect the ocean. The satellite sends out high-frequency radio waves, some of which bounce off the ocean and return to the satellite. Rough, storm-tossed seas return more of the waves, creating a strong signal, while a mirror-smooth surface returns a weaker signal. To learn to match wind speeds with the type of signal that returns to the satellite, scientists compare wind measurements taken by ocean buoys to the strength of the signal received by the satellite. The more measurements scientists have, the more accurately they can correlate wind speed to the returning radar signal. Typhoons and hurricanes are relatively rare. This means that scientists have few buoy measurements to compare to the data they get from the satellite and can't match the satellite measurements to exact wind speeds. Instead, the image provides a clear picture of relative wind speeds, showing how large the strong center of the storm is and which direction winds are blowing. To learn more about measuring winds from space, check out NASA's Winds [ http://winds.jpl.nasa.gov/index.cfm ] web site. NASA image courtesy the QuikSCAT Science Team at the Jet Propulsion Laboratory
Super Typhoon Sepat
Title Super Typhoon Sepat
Description Super Typhoon Sepat came ashore in Taiwan on August 17, 2007, after bringing torrential rain and flooding to the Philippines the day before. Flights to and from Taipei, Taiwan's capital, were canceled, and Chinese authorities were taking emergency measures in anticipation of the powerful typhoon coming ashore on the mainland, said news reports. The typhoon reached Category 5 typhoon, [ http://www.nhc.noaa.gov/aboutsshs.shtml ] the very top of the scale, with sustained winds of 184 kilometers per hour (114 miles per hour), according to CNN. This data visualization of the storm shows observations from the QuikSCAT satellite on August 17, 2007, at 5:39 p.m. local time (9:39 UTC). At this time, Sepat was poised to come ashore onto Taiwan. Peak winds were around 220 km/hr (130 mph, 120 knots), according to Unisys Weather's Hurricane Information page, [ http://weather.unisys.com/hurricane/ ] a Category Four strength typhoon. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. QuikSCAT measurements of the wind strength of Sepat and other tropical cyclones can be slower than actual wind speeds. QuikSCAT's scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction. To relate the radar signal to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to exact wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
The Beginnings of Typhoon Ha …
Title The Beginnings of Typhoon Hagibis
Description Although it eventually reached ?Super Typhoon? status, on May 15, 2002, Typhoon Hagibis was just getting started in the western Pacific Ocean north of New Guinea. This QuikSCAT image shows the wind speed and direction, with speeds categorized from 0.5 meters per second (1.1 miles per hour, darkest blue) to 12.5 meters per second (27.9 miles per hour, red) and higher. Black arrows mark the direction of the air flow. The storm tracked westward for a time towards the Philippines before turning northeast. As of May 22, wind speeds had dropped to under 70 miles per hour, and the storm was several hundred miles east of Japan. Though it's rather early in the season for typhoon development, the western Pacific is unusually warm for this time of year, and the warmer temperatures are fueling earlier storms. Image provided by W. Timothy Liu, NASA Jet Propulsion Laboratory Scatterometry Team, [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://winds.jpl.nasa.gov/ ] Pasadena, CA.
Tropical Cyclone Bondo
Title Tropical Cyclone Bondo
Description The Seychelles are a chain of islands stretching out north of Madagascar off the eastern coast of Africa. On December 20, 2006, these islands were on alert for the very intense tropical cyclone Bondo, which was predicted to strike the islands in the early hours of the next day. Cyclone Bondo was a Category 4 [ http://www.nhc.noaa.gov/aboutsshs.shtml ] storm on the Saffir-Simpson scale, with sustained winds as high as 222 kilometers per hour (138 miles per hour), according to the Reuters news service. This data visualization shows Cyclone Bondo while it was two days away from the Seychelles. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The data were obtained by NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite on December 19, 2006, at 5:03 p.m. local time (14:03 UTC). Bondo appears as a well-formed symmetrical spiral of winds centered around a strong, relatively calm eye. This pattern is typical of tropical cyclones. Since Bondo is in the Southern Hemisphere, the Coriolis force (see glossary [ http://earthobservatory.nasa.gov/Library/glossary.php3?mode=alpha&seg=b&segend=d ]for a definition), which gives all cyclones their spin, turns the storm in the opposite direction to hurricanes and typhoons that form in the Northern Hemisphere: clockwise rather than counterclockwise. Ground- or aircraft-based measurements of the wind strength of Tropical Cyclone Bondo would likely show sustained winds significantly higher than those indicated by QuikSCAT. QuikSCAT employs a scatterometer, which sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction. Tropical cyclones, however, are difficult to measure. To relate the radar "return signal" to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr, or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to exact wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, [ http://winds.jpl.nasa.gov/ ] and the Jet Propulsion Laboratory.
Tropical Cyclone Dora
Title Tropical Cyclone Dora
Description Powerful winds spiral in towards the calm center of Tropical Cyclone Dora in this image made from data captured on February 5, 2007, by the SeaWinds Scatterometer [ http://winds.jpl.nasa.gov/ ] on NASA's QuikSCAT satellite. The satellite records wind speed and direction at an altitude of 10 meters above the ocean's surface. Wind speed is represented by color in this image, with the strongest winds in purple, and the calmest areas in blue. The barbs indicate both wind direction and rainfall. Areas of heavy rain are marked with white barbs. Not surprisingly, the strongest winds and heaviest rain surround the eye of the storm, which is an island of blue, indicating light winds, surrounded by the reds and purples of powerful winds. At the time this image was taken (13:20 UTC), Dora was dissipating from a Category 4 cyclone, reported the University of Hawaii's Tropical Storm Information Center. [ http://www.solar.ifa.hawaii.edu/Tropical/tropical.html ] The storm formed on January 28 over the central Indian Ocean. As it moved south, the storm intensified until its winds peaked at 213 kilometers per hour (132 mph, 115 knots), making it the equivalent of a weak Category 4 hurricane. By February 5, when QuikSCAT observed the storm, it had winds of 120 kilometers per hour (75 mph, or 65 knots) with gusts to 148 kilometers per hour (92 mph, 80 knots). As of February 6, the storm was expected to disintegrate as it moved south over cooler waters. Dora was not forecast to threaten land, though this image shows the outer edges of the storm over Rodrigues Island. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, [ http://winds.jpl.nasa.gov/ ] and the Jet Propulsion Laboratory.
Tropical Cyclone Dora
Title Tropical Cyclone Dora
Description Powerful winds spiral in towards the calm center of Tropical Cyclone Dora in this image made from data captured on February 5, 2007, by the SeaWinds Scatterometer [ http://winds.jpl.nasa.gov/ ] on NASA's QuikSCAT satellite. The satellite records wind speed and direction at an altitude of 10 meters above the ocean's surface. Wind speed is represented by color in this image, with the strongest winds in purple, and the calmest areas in blue. The barbs indicate both wind direction and rainfall. Areas of heavy rain are marked with white barbs. Not surprisingly, the strongest winds and heaviest rain surround the eye of the storm, which is an island of blue, indicating light winds, surrounded by the reds and purples of powerful winds. At the time this image was taken (13:20 UTC), Dora was dissipating from a Category 4 cyclone, reported the University of Hawaii's Tropical Storm Information Center. [ http://www.solar.ifa.hawaii.edu/Tropical/tropical.html ] The storm formed on January 28 over the central Indian Ocean. As it moved south, the storm intensified until its winds peaked at 213 kilometers per hour (132 mph, 115 knots), making it the equivalent of a weak Category 4 hurricane. By February 5, when QuikSCAT observed the storm, it had winds of 120 kilometers per hour (75 mph, or 65 knots) with gusts to 148 kilometers per hour (92 mph, 80 knots). As of February 6, the storm was expected to disintegrate as it moved south over cooler waters. Dora was not forecast to threaten land, though this image shows the outer edges of the storm over Rodrigues Island. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, [ http://winds.jpl.nasa.gov/ ] and the Jet Propulsion Laboratory.
Tropical Cyclone Favio
Title Tropical Cyclone Favio
Description Cyclone Favio was closing the gap between Madagascar and mainland Africa on February 21, 2007, preparing to strike Mozambique in coming days. The Joint Typhoon Warning Center forecast issued at 12:00 UTC (2:00 p.m. Mozambique local time) on February 21 indicated that Favio had sustained wind speeds of 100 knots (about 185 kilometers/hour, 115 miles/hour), with gusts up to 125 knots (about 232 kilometers/hour, 144 miles/hour), which made it a Category 3 storm. The forecast called for the storm to weaken before making landfall within 24 hours, but the impacts were still expected to be severe. The country was already water-logged from heavy rains associated with the onset of the monsoon, and severe flooding along the Zambezi River [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=14115 ] in mid-February killed dozens of people and forced more than a hundred thousand people to evacuate, according to reports [ http://www.reliefweb.int/rw/RWB.NSF/db900SID/LSGZ-6YMDSC?OpenDocument ] from the International Federation of Red Cross and Red Crescent Societies posted online by ReliefWeb. [ http://www.reliefweb.int/rw/dbc.nsf/doc100?OpenForm ] This data visualization shows Cyclone Favio in the middle of the Mozambique Channel between the island of Madagascar and Africa. The data were obtained by NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ], satellite on February 21, 2007, at 6:38 a.m. local time (3:38 UTC). The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. Favio appears as a well-formed spiral of winds centered around a strong eye where winds were calmer. This pattern is typical of tropical cyclones. Since the storm is in the Southern Hemisphere, the Coriolos force, which gives all hurricanes and cyclones their spin, turns the storm clockwise, the opposite direction to hurricanes and typhoons which form in the Northern Hemisphere. Measurements of the actual wind strength of cyclones are often higher than those measured by QuikSCAT. QuikSCAT employs a scatterometer, which sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. This technique does not work over land, but allows measurements in storms over oceans. Tropical cyclones, however, are difficult to measure. To relate the radar energy returned to the sensor to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Tropical Cyclone Gamede
Title Tropical Cyclone Gamede
Description Tropical Cyclone Gamede was spinning in the middle of the Indian Ocean on February 21, 2007, when it was observed by NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite at 5:03 p.m. local time (13:03 UTC). The nearest land to the storm system was Diego Garcia, several hundred miles north of the storm. This data visualization of QuikSCAT's observations shows Cyclone Gamede and its spiral pattern of winds. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. Gamede appears as a well-formed spiral of winds centered around a strong eye with a calmer center. This pattern is typical of tropical cyclones. Since the storm is in the Southern Hemisphere, the Coriolos force, which gives all such storms their spin, turns the storm clockwise, the opposite direction of hurricanes and typhoons that form in the Northern Hemisphere. According to the University of Hawaii's Tropical Storm Information Center, [ http://www.solar.ifa.hawaii.edu/Tropical/tropical.html ] Cyclone Gamede had sustained winds around 45 knots (83 kilometers per hour, 52 miles per hour) at the time of the QuikSCAT observations. Measurements of the actual wind strength of cyclones are often higher than those measured by QuikSCAT. QuikSCAT employs a scatterometer, which sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. This technique does not work over land, but allows measurements in storms over oceans. Tropical cyclones, however, are difficult to measure. To relate the radar energy that returns to the sensor to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Tropical Cyclone Gamede
Title Tropical Cyclone Gamede
Description Tropical Cyclone Gamede was off the shore of Madagascar not far from the Mascarene Islands of Réunion and Mauritius on February 23, 2007, when it was observed by NASA's s QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite at 11:21 p.m. local time (2:21 UTC, February 24). The storm was not passing over any land nor anticipated to do so, according to the Joint Typhoon Warning Center, [ https://metocph.nmci.navy.mil/jtwc.php ] but it brought storm surge to coastal communities in Madagascar and the Mascarene Islands, and very heavy rain fell in several areas. This data visualization of QuikSCAT's observations shows Cyclone Gamede and its spiral pattern of winds. The image shows wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. Gamede was well-formed, with winds spiraling around a distinct, calmer eye. This pattern is typical of tropical cyclones. Since the storm was in the Southern Hemisphere, the Coriolos force, which gives all cyclones their spin, turned Gamede clockwise, the opposite direction to hurricanes and typhoons that form in the Northern Hemisphere. According to the University of Hawaii's Tropical Storm Information Center, [ http://www.solar.ifa.hawaii.edu/Tropical/tropical.html ] Cyclone Gamede had sustained winds around 90 knots (165 kilometers per hour, 103 miles per hour) at the time of the QuikSCAT observations. Measurements of the actual wind strength of cyclones measured near the surface or from aircraft often document sustained winds higher than those estimated by QuikSCAT. QuikSCAT uses a scatterometer, which sends pulses of microwave energy through the atmosphere to the ocean surface and measures the strength of signal that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. This technique does not work over land, but allows measurements in storms over oceans. Tropical cyclones, however, are difficult to measure. To relate the strength of the signal that bounces back to the radar to actual wind speed, scientists compare measurements taken from buoys or other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have enough information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to exact wind speed difficult. Instead, the scatterometer provides a general picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, [ http://winds.jpl.nasa.gov/ ] and the Jet Propulsion Laboratory.
Tropical Cyclone Gonu
Title Tropical Cyclone Gonu
Description This data visualization shows Tropical Cyclone Gonu and its spiral pattern of winds as recorded by NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite on June 4, 2007. Varying wind speeds within the storm form a bull's-eye of color, with the highest wind speeds shown in purple in the center of the storm and gradually decreasing speeds radiating outward. Wind direction is depicted with small barbs. White barbs point to areas of heavy rain. You might expect to see such a well-developed storm hovering over the warm waters of the Caribbean or in the South Pacific, but Tropical Cyclone Gonu showed up in an unusual place. On June 4, 2007, when it was observed by the QuikSCAT satellite, Cyclone Gonu was approaching the northeastern shore of Oman, a region better known for hot desert conditions. Though rare, cyclones like Gonu are not unheard of in the northern Indian Ocean basin. Most cyclones that form in the region form over the Bay of Bengal, east of India. Those that take shape over the Arabian Sea, west of the Indian peninsula, tend to be small and fizzle out before coming ashore. Cyclone Gonu is a rare exception. As of June 4, 2007, the powerful storm had reached a dangerous Category 4 [ http://www.nhc.noaa.gov/aboutsshs.shtml ] status, and it was forecast to graze Oman's northeastern shore, following the coastline of the Gulf of Oman. According to storm statistics maintained on Unisys Weather, [ http://weather.unisys.com/hurricane/ ], the last storm of this size to form over the Arabian Sea was Cyclone 01A, which tracked northwest along the coast of India between May 21 and May 28, 2001. Unlike Gonu's forecasted track, Cyclone 01A's path never brought it ashore. Ground or aircraft-based measurements of the wind strength of Cyclone Gonu would likely show sustained winds significantly higher than those estimated by QuikSCAT. QuikSCAT uses a scatterometer, a device that sends pulses of microwave energy through the atmosphere to the ocean surface and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. This technique does not work over land, but allows measurements in storms over oceans. Wind speeds in trropical cyclones, however, are difficult for QuikSCAT to measure. To relate the radar signal the sensor measures to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have enough corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr, or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Tropical Cyclone Percy
Title Tropical Cyclone Percy
Description Already a powerful Pacific cyclone, Cyclone Percy exploded from a Category 4 storm to a Category 5 cyclone on March 2, 2005. NASA's QuickSCAT satellite captured the change in the above images, taken on March 1 and March 2. The images depict wind speed in color and wind direction with small barbs. The top image shows Percy early on March 1, as the storm was strengthening from a Category 3 storm to a Category 4 storm. The highest wind speeds, shown in purple, are scattered around the center of the storm. By early the next day (lower image), the strongest winds were well-organized around the eye of the storm, resembling a "mini-cyclone." As indicated by the darker shade of purple, the winds are also stronger than they were the previous day. Winds had strengthened around the outer edges of the storm as well. On March 2, high winds represented in red extend further out from the center of the storm, and the lower wind speeds shown in green and yellow cover a smaller area. When the lower image was taken on March 2, Percy was a Category 5 storm, with sustained winds of 260 kilometers per hour (161 mph) and gusts to 315 kph (196 mph). At the time, the storm was over open waters, missing the island nation's Palmerston atoll by 160 kilometers. The images, however, reveal lower wind speeds. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones, however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists don't have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 kilometers per hour or 58 miles per hour). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. After these images were taken, Cyclone Percy weakened and continued to move south. It is expected to continue to weaken and should just sideswipe the more populated capital of the Cook Islands, Rarotonga. Earlier in the week, Percy destroyed most of the structures on Pukapuka and Nassau, two of the northern Cook Islands. NASA image courtesy the QuickSCAT Science Team [ http://winds.jpl.nasa.gov/ ] at the Jet Propulsion Laboratory.
Tropical Cyclone Percy
Title Tropical Cyclone Percy
Description Already a powerful Pacific cyclone, Cyclone Percy exploded from a Category 4 storm to a Category 5 cyclone on March 2, 2005. NASA's QuickSCAT satellite captured the change in the above images, taken on March 1 and March 2. The images depict wind speed in color and wind direction with small barbs. The top image shows Percy early on March 1, as the storm was strengthening from a Category 3 storm to a Category 4 storm. The highest wind speeds, shown in purple, are scattered around the center of the storm. By early the next day (lower image), the strongest winds were well-organized around the eye of the storm, resembling a "mini-cyclone." As indicated by the darker shade of purple, the winds are also stronger than they were the previous day. Winds had strengthened around the outer edges of the storm as well. On March 2, high winds represented in red extend further out from the center of the storm, and the lower wind speeds shown in green and yellow cover a smaller area. When the lower image was taken on March 2, Percy was a Category 5 storm, with sustained winds of 260 kilometers per hour (161 mph) and gusts to 315 kph (196 mph). At the time, the storm was over open waters, missing the island nation's Palmerston atoll by 160 kilometers. The images, however, reveal lower wind speeds. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones, however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists don't have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 kilometers per hour or 58 miles per hour). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. After these images were taken, Cyclone Percy weakened and continued to move south. It is expected to continue to weaken and should just sideswipe the more populated capital of the Cook Islands, Rarotonga. Earlier in the week, Percy destroyed most of the structures on Pukapuka and Nassau, two of the northern Cook Islands. NASA image courtesy the QuickSCAT Science Team [ http://winds.jpl.nasa.gov/ ] at the Jet Propulsion Laboratory.
Tropical Cyclone Sidr
Title Tropical Cyclone Sidr
Description Tropical Cyclone Sidr crept steadily north and west over the warm waters of the Bay of Bengal after forming on November 11, 2007. This image shows the storm as observed by NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite on November 11, 2007. At the time, the center of the developing storm sat west of the southern edge of the Andaman Islands. The colors chart out the storm's wind speed, and not surprisingly, the strongest winds are in the center of the storm. Small barbs show wind direction, and white barbs point to heavy rainfall. On November 12, the Joint Typhoon Warning Center [ https://metocph.nmci.navy.mil/jtwc.php ] forecast that Sidr would grow to the equivalent of a Category 2 storm, with sustained winds of 170 kilometers/hour (100 mph or 90 knots) by November 14. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, [ http://winds.jpl.nasa.gov/ ] and the Jet Propulsion Laboratory.
Tropical Storm Alberto
Title Tropical Storm Alberto
Description Tropical Storm Alberto formed as a tropical depression early in the morning on June 10, 2006, in the Yucatan Channel. This narrow gap of ocean lies between the western end of Cuba and the Yucatan Peninsula at the mouth of the Gulf of Mexico. Alberto gradually gathered strength as it took a slow track northward into the Gulf. By early morning on June 11, wind strength within the storm crossed the critical threshold of 39 knots (70 kilometers per hour, 45 miles per hour), the minimum wind speed necessary to become classified as a tropical storm and hence earn a name. Thus Alberto became the first named storm of the 2006 Atlantic hurricane season. This data visualization shows Alberto in the early stages of formation. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, are offset some distance from the center of the storm, which is not typical. The data were obtained by NASA's QuikSCAT satellite on June 10, 2006 at 23:40 UTC (7:40 p.m. local time). At that time, Alberto had just achieved tropical storm status. The wind direction barbs show that Alberto's center, around which the winds swirled, was located just off the Yucatan Peninsula, even though the strongest winds were over western Cuba. QuikSCAT employs a scatterometer, which sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. This technique does not work over land, which is why there are no measurements over Cuba and the Yucatan in the image shown here. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Tropical Storm Arlene
Title Tropical Storm Arlene
Description Tropical Storm Arlene spins off the southwestern tip of Cuba in this QuikSCAT image captured on June 9, 2005. The vibrant colors in this image depict relative wind speed, with the highest wind speeds in red. Although it is the first tropical cyclone of the 2005 Atlantic hurricane season, Arlene is not a powerful storm. Its strongest winds were maintained around 35 knots about the time this image was acquired. Arlene strengthened slightly the following day, but was not predicted to become an intense hurricane before making landfall. The barbs indicate wind direction. The winds spiral around a calm center in a structure that is typical for a tropical storm, but the most powerful winds do not surround the center of the storm. Represented by red, these winds are north of the center. NASA image courtesy the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ] at the Jet Propulsion Laboratory.
Tropical Storm Barbara
Title Tropical Storm Barbara
Description Tropical Storm Barbara, the second named storm of the 2007 Pacific hurricane season, was swirling off the coast of Mexico on May 29, 2007, when it was observed by NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite at 5:25 p.m. local time (00:25 UTC on May 30, 2007). According to Mexico's National Meteorological Service (Spanish language site), [ http://smn.cna.gob.mx/ ] Barbara had sustained winds that peaked around 100 kilometers/hour (55 mph) on May 29, but had eased off since then. The U.S. National Hurricane Center [ http://www.nhc.noaa.gov/ ] predicted (as of May 31) that the storm most likely would not become a hurricane, but could bring heavy rain to the Mexican and Guatemalan Pacific coastal regions. This data visualization of QuikSCAT's observations shows Tropical Storm Barbara and its spiral pattern of winds. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The storm does not have a clear, rain-free center or a tight spiral shape as would be expected of a larger and more powerful storm. QuikSCAT employs a scatterometer, which sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. This technique does not work over land, but allows measurements in storms over oceans. The Pacific hurricane season begins on May 15 each year, and in 2007, the season had already registered two named storms by the end of the month, Alvin and Barbara. The U.S. National Hurricane Center has only twice before recorded more than one named storm in the Pacific in May (in 1984 and 1956). Hurricane forecasters have been predicting a busy season for hurricanes in both the Pacific and Atlantic basins in 2007, and the early surge of storms is consistent with this forecast. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Tropical Storm Bebinca
Title Tropical Storm Bebinca
Description Tropical Storm Bebinca formed as a tropical depression (area of low air pressure) early in the morning on October 1, 2006, east of the Philippines. Over the course of the next day, the depression gradually moved north and east away from the island chain and gained enough power to become a storm and earn a name. Despite moving farther offshore into the Pacific, Bebinca was largely staying over waters recently cooled by the powerful Typhoon Xangsane, [ /NaturalHazards/natural_hazards_v2.php3?img_id=13913 ] which formed in the same general area approximately a week before Bebinca. The storm system was not expected to develop into a typhoon as of October 5, according to the University of Hawaii's Tropical Storm Information Center. [ http://www.solar.ifa.hawaii.edu/Tropical/tropical.html ] This data visualization shows Bebinca just as the depression was becoming strong enough to be classified as a tropical storm. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The data were obtained by NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite on October 2, 2006, at 09:16 UTC (5:16 p.m. local time). Bebinca appears to be quite asymmetrically shaped at this time, with wind-direction barbs showing that the center of the storm has an area of relatively calm winds, while more intense winds are located in the southwestern portion of the storm. The center, or eye, of the storm is well-defined by wind direction, but the wind speeds are not symmetrical. Weak winds around the storm's center show that the storm system does not have the classic eye and eyewall of a typhoon, which a more intense storm would have. QuikSCAT employs a scatterometer, which sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. This technique does not work over land, and hence the lack of measurements over the Philippine Islands shown here. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Tropical Storm Dalila
Title Tropical Storm Dalila
Description Tropical Storm Dalila was already starting to fade on July 26, 2007, when the QuikSCAT satellite captured this image. The image shows wind speed in color and wind direction with barbs. The white barbs point to areas of intense rain. Dalila was never a big storm and was just declining from its peak when the data used to create this image were captured. High wind speeds—red and purple—are north of the calm region, represented by a green spot, that marks the center of the storm. In a well-organized storm, high winds circle a calm eye like a bull's eye. Though the wind direction circles the center in neat bands, the storm itself is spread in a horizontal oval instead of a symmetrical circle. Tropical Storm Dalila was the eighth tropical system to form in the East Pacific during the 2007 season, and the fourth named storm. Dalila formed south of Baja California and arced northwest over cooler waters as it degraded. At the time this image was taken, the storm's winds blew at 74-83 kilometers per hour (40-45 knots or 46-52 miles per hour) said UNISYS Weather. [ http://weather.unisys.com/hurricane/e_pacific/2007/DALILA/track.dat ] NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, [ http://winds.jpl.nasa.gov/ ] and the Jet Propulsion Laboratory.
Tropical Storm Noel
Title Tropical Storm Noel
Description Spinning winds around a center of calm defines Tropical Storm Noel in this colorful image, created with data collected by NASA's QuikSCAT satellite. The satellite records wind speed and direction over the ocean by sending radar pulses toward the ocean's surface and measuring the strength of the return signal. By mapping the disturbances on the ocean's surface, scientists can estimate how hard and in which direction the wind is blowing. In this image of Tropical Storm Noel, taken on October 28, 2007, the strongest winds are in the south and west side of the storm and are depicted in purple. A broad area of red points to strong winds, and yellow, green, and blue indicate slower wind speeds. The barbs illustrate wind direction, and white barbs show where rainfall was heaviest. The winds circle around a calm center, depicted in blue. The heaviest rainfall corresponds with the strongest winds in the west side of the storm. Tropical Storm Noel was the sixteenth tropical system to develop in the Atlantic Basin in 2007. Though it was never a strong storm in terms of wind speed, it posed significant danger to the Dominican Republic and Haiti. The slow-moving storm dumped heavy rain on the mountainous Caribbean island that is divided between the two nations. The resulting floods and mudslides killed 25 people in the Dominican Republic with many more still missing, reported CNN on October 30. After striking the Dominican Republic, Noel moved north over Cuba. The National Hurricane Center [ http://www.nhc.noaa.gov/archive/2007/refresh/NOEL+shtml/150444.shtml? ] forecast that the storm would continue northeast over the Bahamas, strengthening slightly, and then weaken as it tracked north over cooler waters. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, [ http://winds.jpl.nasa.gov/ ] and the Jet Propulsion Laboratory.
Typhoon Chanchu
Title Typhoon Chanchu
Description Typhoon Chanchu is shown here as observed by NASA's QuikSCAT satellite on May 10, 2005, at 21:11 UTC (which is May 11, 5:11 a.m. local time). At this time, the typhoon had sustained winds of 140 kilometers per hour (85 miles per hour, 75 knots). Chanchu crossed the threshold to typhoon status only a few hours after this image was captured. The image shows wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Other types of measurements of the wind strength of Typhoon Chanchu show sustained winds slightly higher than those shown by QuikSCAT observations. This difference is because the power of the storm makes accurate satellite measurements difficult. QuikSCAT's scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar signal observed by satellite to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
Typhoon Damrey
Title Typhoon Damrey
Description Tropical Storm Damrey is shown here as observed by NASA's QuikSCAT satellite on September 21, 2005, at 08:43 UTC (4:43 p.m. local time). At this time, the storm had peak sustained winds of around 75 kilometers per hour (45 miles per hour, 40 knots). At the time of this observation, Damrey was not strong enough to be classified as a typhoon (the term for a hurricane in this part of the world), but Damrey was projected to continue to gather strength as it crossed the South China Sea. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. Measurements of the wind strength of Tropical Storm Damrey show sustained winds similar to those shown by QuikSCAT observations. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. However, at the time of this image, Tropical Storm Damrey's winds were still low enough that scientists had reliable comparisons from buoys on which to make wind-speed estimates. As wind speeds increase, however, QuikSCAT's ability to accurately monitor the storm's interior wind speeds will be reduced. Values around coastlines are also less reliable as complex interactions between the land, sea, and air can distort surface wind patterns. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team, and the Jet Propulsion Laboratory.
Typhoon Fitow
Title Typhoon Fitow
Description Typhoon Fitow was coming ashore over Honshu, Japan's largest island, at 6:17 p.m. local time (9:17 UTC) on September 6, 2007, when the QuikSCAT satellite captured the data used to make this image. At this time, Fitow was a Category 2 [ http://www.nhc.noaa.gov/aboutsshs.shtml ] typhoon, with peak winds around 160 kilometers/hour (100 mph, 85 knots). The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. As might be expected, the highest wind speeds (purple) and heaviest rains surround the eye of the storm. The eye itself is green, indicating calmer winds. Typhoon Fitow became a named storm on August 29, 2007. The storm system gradually built in power as it drew towards the main islands of Japan, briefly reaching Category 2 [ http://www.nhc.noaa.gov/aboutsshs.shtml ] strength, then weakening to Category 1 before rebuilding again. It was forecast to lose power as it tracked over Honshu. "Fitow" is a Micronesian word for a flower found on the island of Yap. The list of names of western Pacific storms, maintained by the Hong Kong Observatory, draws on Asian languages. QuikSCAT measurements of the wind strength of Typhoon Fitow and other tropical cyclones can be slower than actual wind speeds. QuikSCAT's scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction. To relate the radar signal to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to exact wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. NASA image courtesy of David Long, Brigham Young University, on the QuikSCAT Science Team [ http://winds.jpl.nasa.gov/ ], and the Jet Propulsion Laboratory.
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