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25 Years of atmospheric sciences at Langley
Celebrating Earth Day with research accomplishments
To commemorate Earth Day, Atmospheric Sciences at NASA Langley,
marking its twenty-fifth anniversary as a major field of study this
year, highlights research contributions that ultimately have
increased the awareness of how human activities impact the
atmosphere.
After a quarter century of investigating atmospheric processes
from the air, land, sea and space, NASA Langley researchers have
developed new technologies and made scientific discoveries that
revolutionized how scientists study and understand Earth’s
atmosphere. A list of accomplishments and new research of
Langley’s major space-based instruments and multi-platform
field experiments follows:
A First in Atmospheric Sensing
Langley researchers were the first to develop and operate a
space-based atmospheric LIDAR (Light Detection and Ranging –
an atmospheric sensing instrument). The Lidar In-Space Technology
Experiment (LITE) instrument was flown on the Space Shuttle
Discovery in 1994, proving that space-based lidar measurements
could offer invaluable data unavailable by other means. Among the
many accomplishments of LITE, these data provided the first highly
detailed global view of the vertical structure of cloud and
aerosols from the Earth's surface through the middle stratosphere
as well as sensitive observations of the distribution of dust,
smoke and other aerosols. The success of the LITE instrument paved
the way for a new lidar-based satellite, Pathfinder Instruments For
Cloud and Aerosol Spaceborne Observations—Climatologie Etendue
des Nuages et des Aerosols (PICASSO-CENA), developed by Langley
researchers that is scheduled to launch in 2004.
Documenting Environmental Progress
September 2001 marks the HALOE (Halogen Occultation
Experiment) instrument's tenth year in orbit aboard the Upper
Atmosphere Research Satellite with flawless operation. After a
decade of measuring ozone and trace gases in the upper atmosphere,
HALOE tells an environmental success story. It is the only
space-based instrument that monitored the reduction and leveling
off of chlorine in the stratosphere due to reduced
chlorofluorocarbon (CFC) production. HALOE has also improved the
understanding of ozone depletion in the stratosphere.
Monitoring Volcanic Eruptions and Ozone
The Stratospheric Aerosol and Gas Experiment II (SAGE II)
mission has monitored aerosol, ozone and other trace gases from
space since 1984. A major contribution of this instrument is the
long record of ozone data it has provided. These data have proven
to be an invaluable asset to the United Nations Environment Program
for assessing ozone trends. Other SAGE II data gave researchers a
better understanding of the influence human activities have on
aerosols in the atmosphere as well as the long-term global climatic
effects of the 1991 Mt. Pinatubo volcanic eruption. The SAGE III
mission will build upon the success of SAGE II with a launch
scheduled during 2001.
Understanding the Earth’s Lower Atmosphere
Tropospheric processes have wide-ranging effects within the
atmosphere, so a detailed understanding of these is essential for
an accurate picture of global climate change. So important is the
understanding of these processes that the National Academy of
Sciences established the Global Tropospheric Chemistry Program on
behalf of the United States’ effort in an international
research program designed to study the troposphere. The Global
Tropospheric Experiment (GTE), managed by Langley, is NASA’s
contribution to this project.
The GTE is a program of aircraft-based experiments dedicated to
improving the knowledge of global tropospheric chemistry and its
implications for the biosphere, climate, and stratosphere. Past GTE
missions provided measurements about ozone production and loss in
the remote troposphere, a baseline against which to measure future
pollution impacts on the troposphere, and new information for
climate models. The latest GTE mission, the Transport and Chemical
Evolution over the Pacific (TRACE-P) experiment, is currently
taking place in the western Pacific off the coast of Asia and will
study the impact of a major industrial revolution on the
composition and chemistry of the atmosphere.
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