For Release: Nov. 26, 1997
Release No. 97-127c (UPDATE W/ LAUNCH DATE CHANGE)
New Satellite to be Launched Nov. 27
SCIENTISTS TO USE SPACE PLATFORM TO STUDY CLOUDS
Pictures from space often show the Earth covered by clouds. In
fact, more than 50 percent of the Earth is covered by clouds at any
one time. NASA Langley's latest satellite instrument, the Clouds
and the Earth's Radiant Energy System
(CERES), will use the vantage point of space to provide
global data on the Earth's energy balance and how it is changed by
"The temperature of the Earth is controlled by the global
balance between the amount of sunlight absorbed by the Earth, a
heat gain, and the amount of energy radiated back to space at
thermal infrared wavelengths, a heat loss. Clouds are the largest
factor changing this flow of radiation into and out of the Earth,"
said Dr. Bruce Wielicki, head of the CERES project.
Thin, high clouds can trap heat emitted by the Earth producing
warming. Low, thick clouds can reflect the Sun's energy back into
space causing cooling. Scientists need to know how different types
of clouds trap or reflect energy, and how much and how often they
do it, in order to understand what effects clouds may have on our
"Uncertainties about the way clouds change the energy available
to heat and cool the Earth is the largest uncertainty in predicting
the magnitude of future climate change caused by increasing
greenhouse gases," Wielicki said.
"Clouds change greatly from the equator to polar regions, from
day to night, and from land to ocean. Fortunately, satellites allow
scientists to observe the complete range of cloud types on the
Earth, as well as to measure their behavior and role in the climate
system," Wielicki said. "A good example of this type of measurement
is to observe the changes in clouds and energy flows which occur
during El Nino. The fortuitous timing of the [CERES] launch will
allow measurements to be taken both during and after the current
major El Nino event."
"[CERES] also will improve the accuracy of solar insolation data
used for determining the sites of solar power plants, solar cookers
in refuge camps, solar refrigerators, etc. This will happen roughly
three to four years after launch," Wielicki said.
CERES, part of NASA's Mission to Planet Earth program, is
scheduled for launch Nov. 27 at 3:40 p.m. EST aboard the
Tropical Rainfall Measuring Mission (TRMM) observatory. NASA TV
will provide live coverage of the TRMM launch from 3:30 - 5:40 p.m.
EST. NASA TV is available on GE-2, transponder 9C (C-Band), located
at 85 degrees West longitude, with vertical polarization and a
frequency of 3880 MHz, and audio at 6.8 Mhz. For more information:
- end -
text-only version of this release