Showing posts with label NASA’s Aqua satellite. Show all posts
Showing posts with label NASA’s Aqua satellite. Show all posts

Satellites Reveal Tornado Tracks in Georgia, Mississippi and Alabama


Tornado tracks from last week's powerful tornado outbreak are visible in data from NASA's Aqua satellite and the Landsat satellite.

Among the more than 150 tornadoes reported on April 27 and 28, 2011, was a rare EF-5 storm. Such a storm has the capacity to collapse a concrete building. The tornado hit Smithville, Mississippi, where it killed at least 14 people, and moved northeast nearly 3 miles toward the Alabama border. It is the first EF5 tornado to occur in Mississippi since 1966, according to the National Weather Service.

An image captured by NASA's Aqua satellite shows the path of exposed ground left in the tornado’s wake. The trail left by the EF5 tornado in Mississippi is much shorter than a similar trail that cuts across northwestern Alabama. The National Weather Service rated this tornado at EF4, with winds around 175 miles per hour, said local news reports. The track was about 12 miles long, and the tornado caused more than 20 deaths.

The image was taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite on April 28. The image was compared to an earlier image taken on April 12, 2011 and the tracks were not present.

The tornado of April 27, 2011 hit Smithville, Mississippi, where it killed at least 14 people, and moved northeast nearly 3 miles toward the Alabama border. This NASA MODIS image shows the path of exposed ground left in the tornado’s wake. The trail left by the EF5 tornado in Mississippi is much shorter than a similar trail that cuts across northwestern Alabama. Credit: NASA MODIS Rapid Response Team, Jeff Schmaltz

Another satellite revealed the track from a tornado that touched down near Griffin, Georgia. In a Landsat image from April 28, 2011, a pale green swath indicated the path of a tornado outside of Griffin, Georgia. The tornado was on the ground between 12:03 and 12:28 a.m. local time on April 28, hours before the image was taken. By the time the funnel cloud lifted, the tornado had covered about 20 miles with a path about half a mile wide, said the National Weather Service. The tornado was an EF3 tornado with winds of about 140 miles per hour.

The Landsat satellite image showed that the tornado moved across lightly populated farmland. Bright-colored spots that appear in the image are buildings, and some were close to storm’s path. The town of Griffin is the nearest community to the storm track in this area. Landsat data was provided by the United States Geological Survey.

Ice Island Calves off Petermann Glacier


Ice Island Calves off Petermann Glacier


On Aug. 5, 2010, Ice Island Calves off Petermann Glacier an enormous chunk of ice, roughly 97 square miles (251 square kilometers) in size, broke off the Petermann Glacier, along the northwestern coast of Greenland. The Canadian Ice Service detected the remote event within hours in near real-time data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite. The Petermann Glacier lost about one-quarter of its 70-kilometer (40-mile) long floating ice shelf, said researchers who analyzed the satellite data at the University of Delaware.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured these natural-color images of Petermann Glacier 18:05 UTC on August 5, 2010 (top), and 17:15 UTC on July 28, 2010 (bottom). The Terra image of the Petermann Glacier on August 5 was acquired almost 10 hours after the Aqua observation that first recorded the event. By the time Terra took this image, skies were less cloudy than they had been earlier in the day, and the oblong iceberg had broken free of the glacier and moved a short distance down the fjord.

Icebergs calving off the Petermann Glacier are not unusual. Petermann Glacier’s floating ice tongue is the Northern Hemisphere’s largest, and it has occasionally calved large icebergs. The recently calved iceberg is the largest to form in the Arctic since 1962, said the University of Delaware.