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Images of Goddard Space Flight Center (GSFC) from February 10, 2006
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Comparing the 1998-1999 La N
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Comparing the 1998-1999 La Nina event to the corresponding 2006 Sea Surface Temperature Anomaly Conditions |
| Abstract |
Are we seeing another La Nina event in 2006? This animation compares the winter 1998-1999 La Nina event to the corresponding 2006 conditions in the Pacific Ocean. This is done by comparing Sea Surface Temperature (SST) anomalies (i.e., differences from normal SST values) between 1999 and 2006. Blue areas indicate ocean regions 5 degrees Celsius (9 degrees Fahrenheit) cooler than the norm. During the 1998-1999 La Nina event this resulted in a distinct area of deep blue stretching across the Pacific Ocean. Through this comparison, one can see that our current ocean temperature conditions do not reflect those same conditions during the 1998-1999 La Nina event. |
| Completed |
2006-05-30 |
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Java Mud Volcano Continues t
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Java Mud Volcano Continues to Grow |
| Description |
On the island of Java, a "mud volcano" has been spewing thousands of cubic meters of mud every day since late May 2006. According to BBC news, British geologists believe that oil and gas drilling ruptured pressurized limestone rock and enabled water and mud to reach the surface. The oil company and others have suggested that the event could be related to the May 27 earthquake near Yogyakarta. [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=13629 ] Regardless of the cause, the volcano has become a major hazard, creating a huge mud lake that buried villages and agricultural land. These images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite show the progression of the mud flow from September 3, 2006, [ http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17389 ] (middle) to February 10, 2006 (top). The bottom image, acquired on March 11, 2005, shows how the area looked before the mud flow began. In these infrared-enhanced, "false-color" images, bare ground appears gray, water appears dark blue, and vegetation appears red. Robust vegetation appears bright red. Although clouds partially obscure the February 10 image, the mud flow's advance can still be detected. In this image, the mud flow has spread beyond the toll road toward the east. Areas of robust vegetation in this image are smaller, although that could be partially due to a difference in season. A scientific survey published in the Geological Society of America's February issue of GSA Today stated that the mud volcano could release between 7,000 and 150,000 cubic meters of mud every day for years. According to Reuters, there was concern that mud might pollute the water, damaging the area's shrimp industry. In an attempt to slow the mud flow, the Indonesian government has approved a plan to drop concrete balls linked by heavy chains into the mouth of the volcano, according to news reports. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ] |
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Tehuano Winds Stir the Pacif
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Tehuano Winds Stir the Pacific Ocean |
| Description |
During the winter, Central America may not see much snow, but it does see wind. In southern Mexico, the winds roar out toward the Pacific Ocean through breaks in the western coastal mountains. Called the Tehuano winds, these powerful winds were raging on February 9, 2006. The Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Aqua [ http://aqua.nasa.gov/ ] satellite recorded the impact of the winds on the Gulf of Tehuantepec off the southern coast of Mexico, near the Guatemalan border on February 10, 2006. The top image shows sea surface temperature, with deep purple indicating the coolest temperatures and pinkish yellow indicating the warmest. A swath of intense dark purple—indicating cold water—stretches southward away from the coast. This strip of cold water shows where the Tehuano winds pushed surface waters away from shore, and allowed cold, deep water to well up and replace it. The churning waters brought nutrients up from the bottom of the ocean, and the suffusion of nutrients fertilized plants growing in the surface waters of the ocean, allowing them to grow more quickly. The bottom image shows chlorophyll concentration measured in milligrams per cubic meter of water, with blue indicating the lowest concentration and yellow indicating the highest. Plants, and thus chlorophyll, are thickest in the band of cold water stirred by the Tehuano winds. In both images, some areas appear black where clouds or sunglint (the reflection of sunlight off the ocean's surface) interfered with the satellite's ability to collect data. Land appears gray in both images. The powerful Tehuano winds that created the ocean conditions seen here are generated by the interaction between high- and low-pressure weather systems over the Pacific and the Gulf of Mexico. As cold, high-pressure weather systems move southward over the Gulf of Mexico, they produce a pressure gradient between high pressure over the Gulf of Mexico and low pressure over the Pacific. If you walk into an air-conditioned grocery store on a hot summer day, you may feel cool air blowing into your face. This is because air conditioners are not only pumping out cool air, they are often pushing more air into each cubic meter of the store than exists outside. Pressure gradients work in a similar way through southern Mexico and Central America, causing strong winds. Passing through narrow breaks in mountain chains, the winds intensify. Once they reach the Pacific, they affect the ocean water, as these images show. NASA image courtesy Norman Kuring, Ocean Color Team [ http://oceancolor.gsfc.nasa.gov/ ] |
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