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Tropical Cyclone Dora
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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. |
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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. |
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Tropical Cyclone Favio
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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. |
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Tropical Cyclone Gamede
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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. |
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Tropical Cyclone Gamede
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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. |
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Tropical Cyclone Gonu
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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. |
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Tropical Cyclone Sidr
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Tropical Cyclone Sidr |
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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. |
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