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MAPS
OF FALLING WATER: THREE YEARS OF TRMM DATA
NEW SATELLITE-GENERATED
RAIN MAPS PROVIDE AN IMPROVED LOOK AT TROPICAL RAINFALL
New detailed
satellite-generated rain maps paint a more accurate picture
of how much rain falls in the tropics. These new maps provide
more accurate tropical rainfall measurements and may enable
better management of water resources, may provide clues to
developing El Niños and La Niñas, and give scientists a better
understanding of how latent heat generated from tropical rains
influences weather around the world.
Robert Adler
of NASA’s Goddard Space Flight Center in Greenbelt, Md., presented
new detailed rain maps from data gathered by NASA’s Tropical
Rainfall Measuring Mission (TRMM) satellite at a press briefing
during the American Geophysical Union’s Fall 2000 meeting
in San Francisco.
The TRMM rain
maps incorporate both high-resolution microwave and precipitation
radar data, and depict monthly rainfall since1998 over an
area from 38 degrees North latitude to 38 degrees South.
"Before
TRMM, there was a great degree of variability in monthly rainfall
estimates," says Marshall Shepherd, Goddard research
meteorologist. The measurements from TRMM are helping to improve
that situation, although it will take further analysis to
fully utilize the data.
TRMM monthly
rainfall maps are produced by a team of Goddard scientists
led by Adler, the TRMM Project Scientist, which merges the
TRMM Microwave Imager (TMI), Precipitation Radar (PR), geosynchronous
infrared data and rain gauge data. Monthly rain maps produced
in this manner are thought to provide more accurate rainfall
totals by exploiting the strengths of multiple data sources.
According to
Adler, "This technique uses TRMM to calibrate or adjust
the rain estimates from the other satellites which are not
as accurate, and provides more ‘looks’ at the rainfall systems
which can vary very rapidly. Adler said that scientists are
"using TRMM as a ‘flying rain gauge’ and exploiting its
more accurate measurements along with the additional satellite
information to provide the most complete rainfall estimate."
Another important
result of TRMM’s rain maps is the ability to see changes in
rainfall amounts over a region. "These rainfall anomalies
help to clearly identify flooded and dry regions and how they
may be tied into other processes," Adler said. His findings
show a strong correlation between abnormally high rainfall
in the eastern Pacific Ocean and a developing El Niño, and
unusually low rainfall in that region tied to developing La
Niñas.
Because El Niños
and La Niñas have a major impact on flooding and drought distribution
around the world, Adler’s findings have implications for better
water resource management in the future. The findings will
also assist in planning disaster relief and preparations for
vector-borne disease outbreaks when flooding and extreme heat
is predicted.
"These rain
maps have implications for understanding how latent heating
in the tropics affects weather and climate circulations. Rainfall
is a signature of the latent heat energy, that ‘fuels’ global
wind circulation," Shepherd noted. Armed with more accurate
global rainfall information, scientists also hope to improve
the accuracy of short-term weather forecasts and longer-term
climate projections.
TRMM is a joint
U.S.-Japanese mission and part of NASA's Earth Science Enterprise,
a long-term research program designed to study the Earth's
land, oceans, air, ice and life as a total system. The TRMM
satellite was launched on November 27, 1997.
Special
Thanks to Dr. Marshall Shepherd, Research Meteorologist and
Tropical Rainfall Measuring Mission (TRMM) Outreach Scientist
Dr. Shepherd's email address is: shepherd@agnes.gsfc.nasa.gov
This
multimedia project is the work of a dedicated team of researchers,
animators, and media specialists. A detailed companion video
to this web site is available from NASA TV.
The
following agencies, departments, and researchers provided
expertise and data for this production: NASA - Goddard Space
Flight Center Scientific Visualization Studio Television Production
NASA-TV/GSFC GSFC Studio 13.
Content
Preparation & Project Production: Michael Starobin
GSFC Public Affairs Contact: Lynn Chandler
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