21 February 2006
On February 9, ESRL scientists from the Chemical Sciences Division and the Global Monitoring Division concluded a 4-week period of airborne observations for the Costa Rica Aura Validation Experiment-2 (CR-AVE2). Over a dozen flights were completed from the base at San Jose, Costa Rica, (10 degrees North latitude) to the Equator. Extensive sampling occurred in under sub-visible cirrus conditions of the tropical upper troposphere/lower stratosphere region.
Background: The CR-AVE2 mission is part of a series of Aura Validation Experiments aimed, in part, at validating the trace gas measurements of the NASA Aura satellite in the tropics and subtropics. Aura was launched 15 July 2004 to measure the composition of Earth's atmosphere, particularly with regard to ozone and water vapor. It is expected to operate until 2010. Several science questions form the core of the CR-AVE2 mission objectives, including investigating the budget of ozone and water vapor in the tropical tropopause layer; testing transport mechanisms in the tropical tropopause, a key region of atmospheric transport from the troposphere to the stratosphere; and examining processes related to cirrus clouds in this region. CR-AVE2 began with integration and test flights in Houston January 4-12, in preparation for the January 14-February 10 flight period based in San Jose, Costa Rica. Payload "A" flew on the NASA WB-57F high-altitude research aircraft during the first two weeks. Instruments on that payload focused on remote sensing techniques, and include CSD's instruments for ozone, water vapor, pressure/temperature, and single-particle chemical characterization. Payload "B" took over for the second half of flights, incorporating additional in-situ measurements, including CSD's soot photometer and the CSD chemical ionization mass spectrometer for measuring nitric acid (HNO3) and hydrochloric acid (HCl).
Significance: The CSD research contributions to CR-AVE2 are focused on science questions that address NOAA's objectives within the Climate Goal/Climate Forcing Program. The flights are expected to provide data that will enable researchers to gain new insights into climate/trace-gas/cloud interactions in the tropical tropopause, a key region of atmospheric transport and transformation.