The above images, derived from NASA QuikScat satellite data, show
the extensive pattern of rain water deposited by Hurricanes Katrina and
Rita on land surfaces over several states in the southern and eastern
United States. These results demonstrate the capability of satellite
scatterometers to monitor changes in surface water on land.
The color scale depicts increases in radar backscatter (in decibels)
between the current measurement and the mean of measurements obtained
during the previous two weeks. The backscatter can be calibrated to
measure increases in surface soil moisture resulting from rainfall. The
yellow color corresponds to an increase of approximately 10 percent or
more in surface soil moisture according to the calibration site of Lonoke,
Ark.
The two hurricanes deposited excessive rainfall over extensive regions of
the Mississippi River basin. Basins the size of the Mississippi can take
up to several weeks before such excess rainfall significantly increases
the amount of river discharge in large rivers such as the Mississippi. With
hurricane season not over until November 30, the potential exists for
significant flooding, particularly if new rain water is deposited by new
hurricanes when river discharge peaks up as a result of previous rainfalls.
River discharge should be closely monitored to account for this factor in
evaluating potential flood conditions in the event of further hurricanes.
For more information about the storm, please visit the National Hurricane Center.
QuikScat Background
NASA's Quick Scatterometer (QuikScat) spacecraft was launched from
Vandenberg Air Force Base, California on June 19, 1999. QuikScat carries
the SeaWinds scatterometer, a specialized microwave radar that measures
near-surface wind speed and direction under all weather and cloud
conditions over the Earth's oceans. More information about the QuikScat
mission and observations is available at http://winds.jpl.nasa.gov.
QuikScat is managed for NASA's Science Mission Directorate, Washington,
DC, by NASA's Jet Propulsion Laboratory, Pasadena, CA. JPL also built the
SeaWinds radar instrument and is providing ground science processing
systems. NASA's Goddard Space Flight Center, Greenbelt, MD, managed
development of the satellite, designed and built by Ball Aerospace &
Technologies Corp., Boulder, CO. The National Oceanic and Atmospheric
Administration has contributed support to ground systems processing and
related activities.
