3-D Rain in Katrina

This image of Hurricane Katrina was taken Aug. 28 at 5:30 pm by the Tropical Rainfall Measuring Mission (TRMM) satellite.

Katrina - classified as a Category 4 storm when it hit land early Monday morning - brought 145 mile per hour winds and rising sea levels as it plowed into Louisiana, leaving New Orleans a mess.

TRMM - a joint mission between NASA and Japan Aerospace Exploration Agency - uses the Precipitation Radar, Visible Infrared Scanners, and Tropical Microwave Imager instruments to look into storm clouds and visualize underlying rain structure.

Rainfall measurements give forecasters a hint as to whether a storm is strengthening. As water vapor rises, it cools, condenses into rain, and releases heat - heat that fuels the hurricane.

The higher water rises before cooling, the more intense the storm tends to be. In this image, the tallest towers stretched over 10 miles into the atmosphere. These produce the heaviest rain and are shown here in red. High towers can be a sign that a storm is strengthening and shortly after this image was taken, Irene's winds jumped up to 90 miles per hour.

Blue represents areas with at least 0.25 inches of rain per hour. Green shows at least 0.5 inches of rain per hour. Yellow is at least 1.0 inches of rain and red is at least 2.0 inches of rain per hour.

--Bjorn Carey

Katrina Update

2005 Hurricane Guide

Amazing Images: Science & Nature Photos from Our Readers

Credit: NASA/JAXA