GLAS Calibration and Validation

Between October 16 and November 1, 2003, scientists flew from NASA's Dryden Flight Research Center on several missions to provide calibration and validation of the GLAS lidar channels, particularly the 532 nm channel. Using the Cloud Physics Lidar (CPL), an airborne lidar system designed specifically for studying clouds and aerosols, the researchers hoped to underfly the GLAS within 500 meters of the satellite track over different cloud layers and aerosols. In reality, all flights were successfully completed within just 100 meters of the satellite track.

GLAS and CPL data is invaluable to future research. Retrieval of such cloud microphysical properties, including particle size distribution, number density, and ice/water content will improve cloud models and the understanding of the radiation influence of clouds. The CPL provides an independent and accurate means to remotely sense particle size for cloud modeling, radiation and satellite validation.

ICESat (Ice, Cloud, and land Elevation Satellite) is the benchmark Earth Observing System mission for measuring ice sheet mass balance, cloud and aerosol heights, as well as land topography and vegetation characteristics. The ICESat mission will provide multi-year elevation data needed to determine ice sheet mass balance as well as cloud property information, especially for stratospheric clouds common over polar areas. It will also provide topography and vegetation data around the globe, in addition to the polar-specific coverage over the Greenland and Antarctic ice sheets.

A View of the GLAS Instrument

A Second View of the GLAS Instrument

Contacts:

Matthew McGill
Principal Investigator
Goddard Space Flight Center

William Hart
Data Analysis
Goddard Space Flight Center

Dennis Hlavka
Data Analysis
Goddard Space Flight Center

Judd Welton
GLAS Data
Goddard Space Flight Center

Science Objectives:

• Calibrate and validate measurements from NASA’s GLAS instrument on ICESat.
• Improve the understanding of cloud radiation and microphysical properties of clouds and aerosols
• Develop more advanced remote sensing techniques.
• Provide data within 24 hours of a flight including the cloud and aerosol quick-look pictures, cloud boundaries, and depolarization information

When:

The mission took place between October 16 and November 1, 2003. Flights originated from Edwards AFB, California. Future research will supplement data obtained during this mission.

Where:

Most data was gathered from flights over the Pacific Ocean and western United States, including California, Nevada and Idaho.

Links:

For General Information and Images

http://cpl.gsfc.nasa.gov/

For Information about GLAS

http://glas.gsfc.nasa.gov/

For information about ICESat

http://icsat.gsfc.nasa.gov/