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Isabel's Driving Force
9.22.03
 

Visualization of Hurricane Fabian as it runs through a large patch of warm water
Above: In this visualization, Hurricane Fabian runs through a large patch of warm water, orange and red indicate 82 F and warmer, and leaves a blue cold trail behind. Click image to see annimation of hurricanes cold trail. (4MB)
Credit: NASA/NASDA
Instruments aboard NASA's suite of Earth-observing satellites kept a close watch on Hurricane Isabel last week as it churned toward the East Coast of the United States. Scientists used these space-based tools to look inside Hurricane Isabel and assess the storm's impact.

Hurricanes act as heat engines, drawing energy up from warm tropical ocean waters to power the intense winds, powerful thunderstorms, and immense ocean surges. These tools help weather experts determine if a tropical cyclone is likely to strengthen or weaken and how much rain will fall on land.

Warm Water Fuels Hurricane Isabel

Warm water fuels hurricanes. Hurricanes drive on 82° F or warmer sea surface temperatures. NASA satellites can detect sea surface temperatures through clouds and helps determine if a tropical cyclone is likely to strengthen or weaken. In this visualization, Hurricane Fabian runs through a large patch of warm water, orange and red indicate 82° F and warmer, and leaves a blue cold trail behind. Cold trails can sometimes weaken tropical storms. However, Hurricane Isabel took a different path fueling up on warm water next to Fabian's cold trail, and leaving another cold trail behind. Aqua satellite's Advanced Microwave Scanning Radiometer (AMSR-E) provided sea surface temperatures for the animation above. Data runs from August 22 to September 15, 2003. AMSR-E was developed by the National Space Development Agency (NASDA) of Japan.

Checking Under Isabel's Hood

Spaceborne rain radar allows scientists to create 3-D views of precipitation, height of the rain column and warmth of the core inside powerful hurricanes
Above: Spaceborne rain radar allows scientists to create 3-D views of precipitation, height of the rain column and warmth of the core inside powerful hurricanes. Click image to see "Cat Scan" of Hurricane Isabel. Credit: NASA/NASDA

The eye of a hurricane may be the calm of the storm, but it also houses the engine that drives the storm. NASA and National Space Development Agency (NASDA) of Japan's Tropical Rainfall Measuring Mission (TRMM) satellite looked under Isabel's hood and showed scientists the pistons that power the hurricane, giving them an idea of the intensity and distribution of rainfall.

The world's first and only spaceborne rain radar allows scientists to create 3-D views of precipitation, height of the rain column and warmth of the core inside powerful hurricanes. Red color indicates rain rates in excess of 2 inches per hour. Green represents rain rates in excess of 1.0 inch per hour. Yellow shows excess of .5 inches of rain per hour. TRMM captured this image September 15, 2003.

Eye on Hurricane Isabel

NASA satellites captured many different perspectives of Hurricane Isabel. Twice a day, every day, two satellites, Aqua and Terra , fly over the planet capturing highly detailed images of the Earth.

Satellite image of Hurricane Isabel captured Sept. 17, 2003

Above:The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument onboard NASA's Terra satellite captured this image September 17, 2003.Click to image see animation Credit: NASA

The animated sequence shows eight days of high-resolution images of Hurricane Isabel. These images are so detailed that you can see the wind vortices inside the eye. These images were captured September 8, 10,11,12, 14, 15, 16, and 17, 2003.

Check the National Hurricane Center for the latest storm forecasts.

More information and high resolution images see: NASA Goddard Space Flight Center

To learn more about how hurricanes form see Recipe for a Hurricane
 
 
Rani Chohan
NASA Goddard Space Flight Center