Click
here for the animation described below
A
CLOUDY CLIMATE MYSTERY
Clouds
cause dramatic and dynamic changes in radiation, especially in the tropics where
three sets of thunderstorm clouds (stretching across South America, Africa, and
Indonesia) are visible. These same clouds are one of the major puzzles in predicting
how our future climate might change, as clouds have the power to amplify climate
change or reduce it. CERES measurements will be used with other Terra instruments
to help unscramble this "cloudy" picture and reduce uncertainties in
climate change predictions. This is a 14-day average of thermal energy or heat
emitted to space from March 2000 through May 2001 where levels of energy increase
from blue to red to yellow. The smallest amounts of radiation emitted are over
Greenland and Antarctica, and the greatest amounts of heat emitted are from the
Sahara Desert and the Arabian Peninsula. Cold, blue-colored temperature ranges
are found not only at high latitudes, but also in the tropics from cloud tops
of thunderstorm systems so extensive that they span thousands of miles.
These
new CERES data, available at NASA Langley Research Center's Atmospheric
Sciences Data Center, Hampton, VA, capture incoming and outgoing energy over
the whole planet and provide new insights into climate change.
"The
new data will play a critical role in narrowing the uncertainties in predictions
of future climate change, especially for the undefined role of the Earth's
cloudiness," said Bruce Wielicki, a CERES principal investigator at Langley,
where the CERES mission is managed.
Click
here for the animation described below
CAPTURING DYNAMIC
CHANGES IN THE CLIMATE SYSTEM
Small
water droplets or ice crystals in clouds, snow, and ice reflect most of the incoming
solar energy back to space, but people also affect how much solar energy the Earth
receives and reflects in subtle ways - by adding aerosol particles to the atmosphere
or causing deforestation or reforestation. This is a 14-day average of sunlight
reflected back into space from March 2000 through May 2001. The lowest amount
of reflected solar energy, shown in blue, occurs over clear ocean areas. Green
colors show gradually increasing amounts of reflected sunlight. The areas of greatest
reflected solar energy, shown in white, occur both from the tops of thick clouds
and from ice-covered regions on the Earth’s surface during summer.
For scientists to understand climate, they must also determine what drives
the changes within the Earth's radiation balance. CERES measured some of
these changes over the last year, producing new images that represent data collected
twice per day over the whole planet. CERES captured the May 2001 heat wave
that swept across the southwestern United States. Temperatures soared to
as high as 109 F in parts of California, setting new records.
The
recent U.S. heat wave is only one example of outgoing energy from the Earth.
Everything, from an individual person to the Earth as a whole, emits energy.
As Earth absorbs solar energy, it warms up. To keep our planet at an overall hospitable
temperature, the Earth must emit some of this warmth, or energy, into space.
Earth's outgoing energy has two components: thermal radiation emitted
by the Earth's surface and atmosphere, as in last month's heat wave, and
solar radiation reflected back to deep space by the oceans, lands, aerosols
and clouds.
It is the balance, which scientists refer to as the
Earth's "radiation budget," between the incoming energy from the Sun and
outgoing energy back to space that determines Earth's temperature and climate.
This balance is controlled by both natural and human-induced changes, giving
scientists a wide range of questions to study.
Even though CERES
has the ability to capture short-term changes like the recent heat wave,
"the real power of the CERES data will come from the analysis that integrates
CERES' highly accurate measurement of energy with other measurements from
Terra of the individual components of the climate system," Wielicki said.
The international CERES team is now completing an integration of satellite
data over the entire planet from space-borne instruments on seven different
spacecraft to test the accuracy of global climate models, a task never before attempted.
This will allow a new picture of the energy balance from the top of the atmosphere,
all the way down to the surface of the Earth. Analyzing how well climate
models compare to CERES will tell the researchers which areas most closely
illustrate the Earth's natural responses.
"CERES Terra is providing an
unprecedented observational basis, at just the time when major progress in
understanding our environment by theory and climate modeling is taking place,"
said Leo Donner, a CERES science team member and climate modeler at the National
Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory, Princeton
University, Princeton, NJ.
The Terra spacecraft is part of NASA's Earth
Science Enterprise, a long-term research effort being conducted to determine
how human-induced and natural changes affect our global environment.
