Forum—Teaming Up To Examine Planet
The reason we had so much advance notice of the latest El
Niñothe periodic weakening of trade winds in the Pacific that
causes a shift in ocean currentsis that several environment-monitoring
satellites detected it at its inception last March.
In the next 2 years, the National Aeronautics and Space Administration
(NASA) will launch more than 10 such satellites. This will form what NASA
describes as "the most aggressive constellation of satellites in the
history of this planet." They are designed to give the Earth a complete
physical examination as part of NASA's "Mission to Planet Earth."
The exam may take 25 or more years. The resulting understanding of Earth as
a system should help point to ways to protect the planet's health.
One goal is to predict critical weather and climate conditionsnot 5
days ahead, as is possible with current satellites, but perhaps a month or a
growing season ahead.
This issue's cover story tells how USDA's Agricultural Research Service soil moisture
experts joined with many other scientists supported by NASA to turn the Planet
Earth "stethoscope" on a large swath of Oklahoma to gain new insights
into land-atmosphere interactions that may have parallels with the El
Niño phenomenon. Depending on geography and season, anomalous or
unseasonable conditions in soil moisture over a large enough area can affect
regionaland possibly globalclimates.
The SGP97 (Southern Great Plains 97) project, supported jointly by NASA and
several other federal agencies, is led by Tom Jackson of the ARS Hydrology
Laboratory in Beltsville, Maryland. It is the latest in a series of cooperative
projects with Beltsville scientists dating back to 1978. This cooperative
relationship has been aided by proximity: NASA's Goddard Space Flight Center is
next door to ARS' Beltsville Agricultural Research Center. And Goddard has the
biggest share of NASA's Mission to Planet Earth assignment.
NASA headquarters' land surface hydrology program manager, Ming-Ying Wei, is
as pleased as Jackson is by the data taken in SGP97, saying it gives scientists
the type of knowledge needed to design a global observing system for soil
The Beltsville scientists also work with scientists at NASA's Marshall Space
Flight Center in Huntsville, Alabama, and NASA's Jet Propulsion Laboratory in
Pasadena, California. ARS scientists from other labs, including those in Ames,
Iowa, Riverside, California, and Phoenix and Tucson, Arizona, also work closely
This ARS-NASA cooperation has dividends for other USDA agencies as well. In
1985, the National Agricultural Statistics Service (NASS), Foreign Agricultural
Service, Farm Service Agency, and Natural Resources Conservation Service signed
an agreement under which ARS provides research assistance to improve crop and
land assessment reports.
One very visible result of this cooperation is the biweekly
"greenness" maps that NASS began putting on the World Wide Web last
year. (Go to http://www.nass.usda.gov/research) These maps of the continental
United States use a sensor on a National Oceanic and Atmospheric Administration
satellite to estimate the development and vigor of crops by the amount of
chlorophyll in the leaves.
In 1998, NASA plans to launch the MODIS satellite, which will have a new and
improved sensor to collect data for these maps. It will have better spatial
resolution and be better equipped to handle atmospheric interference.
George Hanuschak, associate director of the research division of NASS, says
that by giving a big picture on crop development and vigor, the maps can
sometimes provide policymakers informative views of an unfolding disaster. One
example was the cold and windy winter of 1995-1996 that, when combined with a
subsequent spring drought, did heavy damage to major winter wheat-growing areas
of the United States.
Paul Doraiswamy, who is with ARS' Remote Sensing and Modeling Laboratory in
Beltsville, has helped NASS develop the mathematics model needed to generate
the greenness maps from the satellite sensor. Doraiswamy is a member of the
vegetative assessment and mapping team for the SGP97 study.
In another project, Doraiswamy is developing methods for integrating data
from satellites with crop simulation models to supplement NASS crop estimates
data. This would be yet another example of the payoffs from USDA-NASA
cooperation, with international implications for everyonefrom farmers to
stockbrokers and crop insurance agents to urban residents.
David A. Farrell
ARS National Program Leader
"Forum" was published in the
April 1998 issue of Agricultural Research magazine. Click here to see this
issue's table of contents.