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NASA
Airborne Expedition Chases Climate, Ozone Questions
06/27/07
WB
– 57
Sunrise
At Ellington
Credit:
NASA / ESPO
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NASA's Tropical
Composition, Cloud and Climate Coupling (TC4) field campaign will
begin this summer in San Jose, Costa Rica, with an investigation
into how chemical compounds in the air are transported vertically
into the stratosphere and how that transport affects cloud
formation and climate.
The study will begin the week of
July 16 with coordinated observations from satellites,
high-flying NASA research aircraft, balloons and ground-based
radar. The targets of these measurements are the gases, aerosols
and ice crystals that flow from the top of the strong storm
systems that form over the warm tropical ocean. These storm
systems pump air more than 40,000 feet above Earth’s
surface, where it can influence the composition of the
stratosphere, home of our planet’s protective ozone
layer.
The outflow of these storms also produces vast
swaths of icy cirrus clouds that play an important role in how
much infrared energy is trapped in Earth's atmosphere. Scientists
want to document the full life cycle of these widespread clouds
-- down to the size and shape of their tiny ice crystals -- to
better understand how Earth will react to a warming
climate.
"This campaign is an unprecedented
opportunity to use NASA's complete suite of satellite and
airborne Earth-observing capabilities to investigate a largely
unexplored region of the atmosphere," said Michael J.
Kurylo, a TC4 program scientist at NASA Headquarters, Washington.
"This tropical transitional layer of the atmosphere between
the troposphere and the stratosphere plays a key role in both
climate change science and atmospheric ozone chemistry. The data
will yield new insights into the composition of this layer and
the impact of the deep clouds that penetrate the atmosphere up
into this layer."
The effort runs through Aug. 8. It
is NASA's largest Earth science field campaign of the year.
"A
mission this complex, with three aircraft, deployment sites in
Costa Rica and Panama, and more than 400 people involved, can be
a real challenge," said Mission Project Manager Marilyn
Vasques of NASA Ames Research Center, Moffett Field,
Calif.
Soaring high above the cloud systems will be a NASA
ER-2 aircraft, which can reach an altitude of 70,000 feet, or 3
miles into the stratosphere. A NASA WB-57 aircraft will fly into
the cirrus clouds and sample the chemical make-up of the storm
systems’ outflow. NASA's DC-8 aircraft will probe the
region between the troposphere and the stratosphere (known as the
tropopause transitional layer) with remote-sensing instruments.
It also will sample cloud particles and air chemistry at lower
altitudes. A weather radar and meteorological balloons will be
deployed in Panama to support the campaign. Additional balloons
will be launched from Costa Rica and San Cristobal Island in the
Galapagos Archipelago.
Observations from seven satellites
will complement the aircraft measurements with large-scale views
of many different features of the atmosphere. For example, the
Aura spacecraft will focus on the chemical composition of the
tropopause transitional layer and measure ozone, water vapor,
carbon monoxide and particles. NASA's Aqua satellite will map
thin cirrus clouds, some of which are so faint they are nearly
invisible to the naked eye. Instruments on the CALIPSO and
CloudSat satellites will pierce the atmosphere to provide
vertical profiles of clouds and aerosol particles that can change
how clouds form.
Along the coasts of Colombia and Panama
south of Costa Rica, the warm summer waters of the Pacific Ocean
are a fertile breeding ground for the type of heat-driven, or
convective, storm systems the mission is targeting. Clouds
produced by these maritime systems produce heavy rainfall and
cloud tops that can reach into the transitional layer.
Mission
scientists want to know what effect a warming climate with rising
ocean temperatures will have on the intensity of these storm
systems. Another unknown is how aerosol particles swept up in
these systems change the clouds and are, in turn, affected by the
clouds.
These tropical convective systems also may play a
role in the recovery of the ozone layer. Estimates of ozone
destruction in the stratosphere typically minimize the impact of
short-lived chemical compounds that presumably could not survive
the long journey there. Mission scientists will investigate
whether the rapid movement of air in these strong convective
systems provides an express route for ozone-destroying compounds
to reach the stratosphere.
The Earth Science Division at
NASA Headquarters is sponsoring the $12 million mission. Costa
Rica's National Center for High Technology, San Jose, and the
University of Panama, Las Tablas, are cooperating with NASA on
the mission as are other U.S. agencies, such as the National
Oceanic and Atmospheric Administration and the National Science
Foundation.
Source:
NASA
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