Press Release

Looking at Clouds From all Sides Now

By SpaceRef Editor
July 17, 2002
Filed under , ,

NASA-led research of cirrus clouds by more than 450
scientists could lead to improved forecasts of future climate
change — forecasts of your weather today, tomorrow and years
into the future.

This month, NASA is conducting a field campaign in southern
Florida to investigate high tropical cirrus clouds composed
of tiny ice crystals. Researchers hope to determine how these
clouds form, how they limit the amount of sunlight reaching
the surface of the Earth and how they trap heat rising from
the surface and lower atmosphere. This key information will
provide data that will markedly improve our understanding of
these cloud systems, and thereby improve the computer models
used to forecast global climate change and its regional
impacts.

High, tropical cirrus clouds are made up of tiny ice crystals
that float at altitudes from 20,000 feet to 60,000 feet.

The campaign includes deployment of six aircraft over two
surface sites ranging in altitude from near surface to 70,000
feet. A modeling team is supporting flight planning,
preliminary data analysis to help validate the instruments’
integrity, and subsequent modeling and analysis with the goal
of developing a more complete understanding of these cloud
systems.

The aircraft will sample air flowing into and being processed
by the cloud systems and will evaluate the composition and
structure of the resulting cirrus clouds. One of the six
aircraft, the NASA ER-2, will serve as a remote sensing
platform to support satellite measurements and to extract
details of the cloud structures.

Recent observations from NASA’s Terra satellite, with
improved sensitivity to detect cirrus cloud systems, suggest
that cirrus are present more than expected both temporally
and spatially across the planet. Cirrus may act to warm or
cool the planet and the tendency toward warming or cooling
depends on the extent, duration, thickness and location of
the clouds.

Satellite observations can assess the extent of cirrus. Field
campaigns, when coupled with concurrent satellite
observations, allow development of a detailed understanding
of the evolution of these cloud systems and verification of
satellite-deduced cirrus characteristics.

“Our objective is to find out how ice clouds affect global
warming and climate change,” said Eric Jensen, project
mission scientist at NASA Ames Research Center, Moffett
Field, Calif. “The combination of measurements and computer-
modeling studies will improve our understanding of how cirrus
clouds may change in response to other aspects of climate
change,” he explained. “For example, if the Earth’s surface
heats up and thunderstorms become more intense, will larger,
thicker cirrus clouds be formed? How might these regional
climate events affect the bigger picture?”

“Clouds are the largest source of uncertainty in computerized
global climate models,” Jensen said. “We want to measure the
ice crystal sizes, cloud optical depths and the heating or
cooling of the Earth’s surface caused by tropical cirrus
clouds, particularly those generated by intense storms.”
Optical depth is a measure of the visual or optical thickness
of a cloud.

The effort is called the Cirrus Regional Study of Tropical
Anvils and Cirrus Layers – Florida Area Cirrus Experiment
(CRYSTAL-FACE). Partner government organizations include the
National Oceanic and Atmospheric Administration, National
Science Foundation, the Department of Defense Office of Naval
Research and the Air Force, and the Department of Energy. The
Naval Air Facility, Key West, Fla., is hosting the aircraft
for this research effort.

This research is part of NASA’s Earth Science Enterprise, a
long-term research effort that utilizes the unique vantage
point of space to view our home planet to better understand
and protect life here, while exploring for life in the
universe. CRYSTAL-FACE will support data validation of NASA
satellite investigations, including EOS Terra and Aqua
satellite missions and the Tropical Rainfall Measurement
Mission.

For more detailed information of the CRYSTAL-FACE mission,
please see:
http://cloud1.arc.nasa.gov/crystalface/

For more information about NASA’s Earth Science Enterprise,
please see:
www.earth.nasa.gov

SpaceRef staff editor.