AIRS Water Vapor-Ground (AWEX-G) Experiment

The Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua spacecraft is making highly accurate measurements of air temperature, humidity, clouds, and surface temperature. The data collected by AIRS will be used by scientists around the world to better understand weather and climate.

This mission involved use of different water vapor profiling radiosondes and Raman lidar systems for acquisition of measurements during AIRS overpasses. The comparison of these measurements with AIRS, through the use of the AIRS forward model, has revealed apparent biases and calibration differences among the various water vapor profiling technologies in current use.

The main goal of this three-week experiment was to confirm that permanently stationed ARM water vapor profilers (Vaisala RS-90s and the CARL lidar) can be used as the profiling standards for AIRS validation and that the mean of a large set of those measurements is accurate to within 5 percent.

Current research is being conducted across the globe, including the Antarctic, to augment this mission's findings and to further improve the quality of AIRS dat a.

The AIRS instrument onboard the Aqua satellite measures atmospheric temperature and humidity; land and sea surface temperatures; cloud propertie; and radiative energy flux.
Credit: NASA

A graphic of measurements in a single-column model diagram from the Atmospheric Radiation Measurement (ARM) Program Southern Great Plains.
Credit: DOE ARM Program

A map of the Southern Great Plains site for the Atmospheric Radiation Measurement (ARM) Program.
Credit: DOE ARM Program

Contacts:

David Whiteman
Lead Scientist
Goddard Space Flight Center, Greenbelt MD

Science Goals:

• Use water vapor measurement technologies over a three-week period under clear weather and during AIRS overpasses for AIRS validation.
• Characterize the measurement differences of the water vapor instruments to better understand the existing differences in the AIRS validation activities.
• Determine a standardized radiosonde launch procedure that can be implemented at the AIRS validation sites.
• Confirm the accuracy of water vapor profilers, in an effort to establish them as the standards for AIRS validation work.

Partners:

About 20 scientists and researchers from NASA, the Department of Energy’s Atmospheric Radiation Measurements Program, NCAR and several universities collaborated to complete the project

When:

October 27 - November 16 2003

Where:

Department of Energy's Southern Great Plains Cloud and Radiation Testbed in Northern Oklahoma

Links:

Project Site

http://r1-sgpc1.sgp.arm.gov/~awex-g/

For information about NASA's Aqua Satellite

http://www.aqua.nasa.gov/

For information about AIRS

http://www-airs.jpl.nasa.gov/

For information about the Atmospheric Radiation Measurement (ARM) Program

http://www.arm.gov/docs/index.html

For information about the Raman Lidar Group

http://ramanlidar.gsfc.nasa.gov/