Press Release

NASA Scientists’ Showdown With Soil Moisture At The O.K. Corral

By SpaceRef Editor
August 2, 2004
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Tombstone, Ariz., is a dusty place known for Wyatt Earp’s famous 1881
“Shootout at the O.K. Corral.” This year, from August 2 to 27, it will
be known as the place where scientists from NASA, the U.S. Department
of Agriculture, the National Oceanic and Atmospheric Administration,
and other institutions gather and study soil moisture to improve
weather forecasts and the ability to interpret satellite data.

By identifying how much moisture is retained in soils, hydrologists
will be able to determine how much more water can be absorbed, and
thus better estimate the potential for flooding, or the amount of
water that can sink into the water table. During July and August, the
U.S. Southwestern monsoon season is characterized by a wind pattern
shift that exerts a strong influence on precipitation and temperatures
across the Western United States, Mexico and adjacent ocean areas.
This change in winds over the region creates many rainy days and heavy
rainfall, which are ideal conditions for studying soil moisture.

The study, called the Soil Moisture Experiment 2004, will use ground
teams, airplanes and NASA satellites and instruments to measure soil
moisture in Tombstone and Sonora, Mexico, where water supplies are

Researchers from NASA, the U.S. Department of Agriculture, the
National Oceanic and Atmospheric Administration, Sonora Research
Institute and more than a dozen universities will be on the ground and
in the air with advanced technology to get a better read on soil
moisture. The Soil Moisture Experiment 2004 scientists also want to
know what atmospheric conditions create long-lasting rainfalls over a
large area. By determining which factors create large or small
rainfall, hydrologists can provide better forecasts and know how much
water will be available to people.

“The Western U.S. relies on water from the Southwestern monsoon system
to fill its aquifers. Accurate measurements of soil moisture will
assist in better water supply forecasts associated with the monsoon in
the water-scarce western U.S,” said Tom Jackson, USDA Agricultural
Research Service hydrologist and lead for the Soil Moisture Experiment

From space, NASA’s Aqua, Terra and QuikScat satellites will provide
various measurements. Aqua’s Advanced Microwave Scanning Radiometer
instrument will measure soil moisture; Terra’s Moderate Resolution
Spectroradiometer will provide vegetation status; and Terra’s Advanced
Spaceborne Thermal Emission and Reflection Radiometer will measure the
surface temperature. The SeaWinds instrument on the QuikScat satellite
will observe the monsoon winds that bring in the moisture from the
Pacific Ocean to the U.S. Southwest.

Closer to Earth, microwave radiometers on the Naval Research
Laboratory P-3 aircraft and the Airborne Visible/Infrared Imaging
Spectrometer on NASA’s ER-2 high-altitude aircraft will fly over the
areas to measure soil moisture. The Airborne Visible/Infrared Imaging
Spectrometer will also help test new methods for remotely sensing
water content in plants. Meanwhile, ground instruments will measure
the temperature and percentage of moisture in soils from 2 to 40
inches deep. The satellite, airplane and ground data will be compared.

The Soil Moisture Experiment 2004 mission adds to two prior soil
moisture experiments in 2002 and 2003, and is part of the larger North
American Monsoon Experiment, led by NOAA, which is dedicated to
understanding how the Southwestern U.S. monsoon season works. Monsoons
need to be accurately understood and predicted by weather and climate
models, because their influence on seasonal weather, including floods
and droughts, can significantly disrupt regional economies and

Dr. Eni Njoku of JPL is a member of the Aqua Advanced Microwave
Scanning Radiometer science team. JPL manages Quikscat, Advanced
Spaceborne Thermal Emission and Reflection Radiometer on Terra, and
Airborne Visible/Infrared Imaging Spectrometer.

NASA’s Earth Science Enterprise is dedicated to understanding the
Earth as an integrated system and applying Earth system science to
improve prediction of climate, weather and natural hazards using the
unique vantage point of space.

For more information and images, on the Internet, visit:

more information about the SMEX Experiment on the Internet, visit:

SpaceRef staff editor.