2002-2003 Science Planning Summary

Geology & Geophysics

Dr. Scott Borg
Program Manager

GO-052-M

NSF/OPP 02-33246
Station: McMurdo and Palmer Stations
RPSC POC: Kelly Brunt
Research Site(s): Arrival Heights, Beacon Valley, TAMDEF GPS ARGO stations

Antarctic mapping, geodesy, geospatial data, satellite image mapping and Antarctic Resource Center management
Mr. Jerry L. Mullins
United States Geological Survey
Geographic Sciences
jmullins@usgs.gov
Dr. Larry Hothem
United States Geological Survey
Dr. Cheryl Hallam
United States Geological Survey

Deploying Team Members: Cheryl A Hallam . Larry D Hothem . Jerry L Mullins . Richard Sanchez . Herbert M Thompson
Research Objectives: Geodetic surveying, aerial photography, remote sensing (principally using several varieties of satellite imagery), and mapping are all activities necessary for the successful operation of a multifaceted scientific and exploration effort in Antarctica. The U.S. Geological Survey provides these support activities to the U.S. Antarctic Research Program.

Year-round data acquisition, cataloging, and data dissemination activities will continue in the U.S. Antarctic Resource Center for geospatial information. Field surveys will be conducted in support of specific research projects, and as part of a continuing program to collect the ground-control data necessary to transform existing geodetic data to an earth-centered system suitable for future satellite mapping programs.

LandSat data will be collected as part of satellite image mapping activities. This will permit continued publication of additional 1:50,000 scale topographic maps in the McMurdo Dry Valleys region. Such topographic studies provide a uniform base map on which to ensure that scientific information (from geology, glaciology, biology and other areas) is spatially accurate. These, as well as the satellite image maps, are used by scientists to plan and execute future research work. Spatially-referenced, digital cartographic data will be produced in tandem with the published maps.

In the austral summer of 2001-2002, this group will collaborate with NASA's Airborne Topographic Mapper Program to collect very high-resolution elevation data in portions of the McMurdo Dry Valleys and vicinity. The detailed land surface characterizations will be tested for feature recognition in the Beacon Valley, glacier studies in the Taylor Valley, and geologic applications in the Mt. Discovery area. The data will be tested for positional accuracy and resampled to provide regularly spaced observations for use in models and science. The USGS team will work with selected scientists to develop elevation data at resolutions that best serve their research needs. The data will then be used to develop elevation models at a variety of resolutions.

Very high-resolution data also will be collected for use by the ICESat (Ice, Cloud, and Land Elevation Satellite) research community to calibrate their 70-meter elevation data in Antarctica. The McMurdo Dry Valleys comprise a primary site for calibration and validation of NASA's ICESat satellite, scheduled for launch in December 2001. The primary sensor on ICESat is a laser altimeter, designed to measure the surface elevation very precisely, within the 70-meter footprint of the laser. Because the altimeter will be operated with off-nadir pointing, it is equally important to calibrate for mounting angle as well as for range. A calibration site for such a sensor requires precise knowledge of local topography, which must be a stable, snow-free surface region with minimal vegetation. Angle calibration is also enhanced if you have variable surface slopes of moderately large amplitude (10-20 degrees). With accurately measured surface elevations, the Dry Valleys provide a nearly ideal calibration site for ICESat. Furthermore, the Dry Valleys are in the region of the maximum altitude for the orbit of ICESat, allowing measurement errors to be detected through comparisons with measurements from other parts of the world. No other site in the world can provide this unique combination of features.


Field Season Overview:
Each year the geographic south pole survey marker moves with the glacier it is embedded in and a new marker is designed and fabricated by station personnel. Thus each field season, the USGS project team members determine and mark the geographic south pole.

USGS team members also provide on-site support for the continuous operation of the GPS geodetic observatory in the CosRay Lab in the Skylab Building. They will perform upgrades and maintenance on the system with the assistance of the station science technician. The team members will train the winter-over science technician to operate the system.

As part of the Trans-Antarctic Mountain Deformation (TAMDEF) program, project team members will travel by helicopter to sites in the Transantarctic Mountains and South Victoria Land near McMurdo Station. They will take simultaneous measurements with deployed GPS receivers and other instruments

Team members will coordinate USGS fieldwork with the GPS measurements of the Italian Geodetic Team at Terra Nova Bay. USGS will also coordinate a continuous operating GPS/GLONASS (GLObal NAvigation Satellite System) observatory system and tide gage calibration activities at Cape Roberts with Land Information New Zealand. The researchers will continue their operation of the GPS/GLONASS receiver and antenna system at the Crary Lab. The station science technician will monitor the system during the austral winter.

No project team members will deploy to Palmer Station. The science technician will maintain the continuously operating GPS reference station at Palmer Station. The technician will assist other groups with establishing GPS coordinates for study sites in the local area as needed throughout the season.