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July 30, 2004
Scientists’ Showdown With Soil Moisture At The O.K. Corral
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 (USDA), the National Oceanic and Atmospheric
Administration (NOAA), 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 how much water sinks 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, or SMEX04, will use ground teams, airplanes and NASA satellites and instruments to measure
soil moisture in Tombstone, Ariz., and Sonora, Mexico, where water supplies are critical.
Researchers from NASA, USDA, NOAA, 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. SMEX scientists also want to know what atmospheric conditions create long-lasting rainfalls over a
large area. By knowing 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 SMEX.
From space, NASA’s Aqua, Terra and QuikScat satellites will provide various measurements. Aqua’s Advanced Microwave Scanning
Radiometer (AMSR-E) instrument will measure soil moisture; Terra’s Moderate Resolution Spectroradiometer (MODIS) will provide vegetation
status; and Terra’s Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) 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
(AVIRIS) on NASA’s ER-2 high-altitude aircraft will fly over the areas to measure soil moisture. AVIRIS 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 SMEX04 mission adds to two prior SMEX experiments in 2002 and 2003, and is part of the larger North American Monsoon Experiment (NAME), 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 populations.
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:
http://www.gsfc.nasa.gov/topstory/2004/ 0729soilshowdown.html
For more information about the SMEX Experiment on the Internet, visit:
http://hydrolab.arsusda.gov/smex04/
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Contacts:
Rob Gutro
Goddard Space Flight Center, Greenbelt, Md.
Phone: 301-286-4044
Gretchen Cook-Anderson
Headquarters, Washington
Phone: 202/358-0836
Sandy Miller Hays
USDA Agricultural Research Service, Washington
Phone: 301/504-1638
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The OK Corral Showdown
On October 26, 1881, Wyatt Earp and his brothers Morgan and Virgil, and Doc Holliday had a famous gunfight with cattle rustlers and thieves called
“the Cowboys.” In 2004, NASA, USDA and NOAA scientists are sampling the famous soils in that region. CREDIT: www.Tombstone1880.com
Collecting Data on the Ground
Hydrologist Tom Jackson and an Alabama A&M University student sample soil moisture in a very dry field during SMEX03 (Soil Moisture Experiment
2003). CREDIT: Stephen Ausmus/USDA ARS
Soil Satellite Simulator
Tom Jackson (USDA) and Peggy O’Neill (NASA) prepare ground based satellite simulator for field experiments. CREDIT: Stephen Ausmus/USDA ARS
Satellite Observations
From space, NASA’s Terra satellite instrument, the Moderate Resolution Spectroradiometer (MODIS) will provide vegetation status to the SMEX
scientists. Credit: NASA/GSFC, Jacques Descloitres
Microwave Data from Aircraft
On board the NASA P-3B aircraft, Marian Klein (foreground), a contractor with NOAA, and hydrologist Tom Jackson examine data collected by a
microwave sensor. CREDIT: Stephen Ausmus/USDA ARS
Lab Testing Soil
Soil moisture samples are processed in the SMEX03 Alabama laboratory by Alabama A&M students Susan Bodner and Mustafa Yousif. Photo by Stephen
Ausmus.
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