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NASA Wallops Conducts Ice Sheet Mapping Missions
September 25, 2007

The NASA P-3 Orion Aircraft with a compliment of scientists and support personnel has spent the past several weeks in Greenland in an effort to observe the current state of the Greenland ice-sheet.

The NASA P-3 Orion is being used for Greenland ice sheet mapping.

The purpose of Global Ice-Sheet Mapping Orbiter 2007 (GISMO2007) mission is to conduct high and low altitude remote sensing in specified locations over the Greenland ice-sheet and to measure both surface and subsurface topography of the ice-sheet. Researchers have been collecting data that will contribute to the ice-sheet mass determination.

There are several goals of this mission. One of the broad-scaled goals is to observe the current topographic state of the Greenland ice-sheet and to test two sensors. In order to accomplish these goals, the surface elevation of the ice and the bedrock elevation beneath the ice are both being measured. The surface elevation is measured using laser altimeters and the bedrock elevation is measured using radar ice-sounders. By collecting both surface and subsurface data, the ice-thickness can be determined, which contributes to the knowledge of the ice-volume.

The data collected on the ice-volume is then compared to previous data collected during missions sporadically since 1991. This study determines the mass-balance, which is a temporal delta of the ice. The mass-balance also describes the gain or loss of the ice-volume as a whole for Greenland. The data from the GISMO2007 mission can be used to examine the state of the ice-sheet.

Four sensors are being flown during this mission. GISMO2007 will test one newly developed NASA Instrument Incubator Program (IIP) sensor, re-fly two previously flown sensors, and fly one university sensor not having previously flown on the P-3.

The GISMO instrument will fly as prime instrument for specific periods of the mission. It is a radar ice-sounder that is part of the NASA Instrument Incubator Program.

The Airborne Topographic Mappers (ATM) is a scanning radar instrument developed at NASA Wallops Flight Facility for the Greenland ice-sheet project. It is primarily used for topographic change detection by repeating measurements over the same area over specific periods.

The Coherent Antarctic Radar Depth Sounder (CARDS), having flown several times in the P-3, is the proven ice-sounder for glacier bedrock profiling. It will fly in conjunction with the ATM altimeters to repeat flight paths previous flown during Arctic missions.

The fourth sensor being flown is the Laser Vegetation Imaging Sensor (LVIS). This is being flown to test its use as a high-altitude, high-resolution altimeter.

The entire GISMO2007 mission consists of 14 P-3 flights based out of Sondrestrom and Thule, Greenland.

Dr. Bill Krabill, NASA Wallops Hydrospheric and Biospheric Sciences Laboratory, is serving as a principal investigator on this mission.