HR: 0830h
AN: C41C-0991    [PDF]
TI: IPY: An excellent opportunity to improve Arctic DEMs and document today's Arctic for future generations
AU: * Nolan, M
EM: fnman@uaf.edu
AF: University of Alaska Fairbanks, 455 Duckering Bldg Institute of Northern Engineering, Fairbanks, AK 99775-5860 United States
AB: Digital Elevation Models (DEMs) are an essential resource for any field or modeling study in the terrestrial Arctic, yet the DEMs available there are currently the worst on the planet. Efforts in the past decade have led to the acquisition of new DEMs for the entire Antarctic continent (Radarsat Antarctic Mapping Project, RAMP) and for nearly all of the planet within +/- 60 degrees latitude (Space Shuttle Radar Topography Mission, SRTM). Thus, the U.S. Arctic is left with 1:63,360 maps made during the IGY times, which does not meet the USGS' own standards for accuracy. Other countries are left in similar circumstances, with DEMs created from paper maps with usually no better than 1:50,000 scale, and there is as yet no central circum-polar clearinghouse for such DEMs. And because nearly all of these DEMs were created by digitizing paper base maps, most contain artifacts of the digitizing process that further reduce their quality. It could be argued that DEMs of the polar regions of the planet Mars are more accurate, consistent, and easily available than those from the Earth's Arctic. Only an organized international effort could possibly manage such a data collection task, and the project seems well suited to the goals of the International Polar Year. Perhaps being last in line for new DEMs is actually beneficial in this case, as technological improvements have led to new acquisition systems that are more accurate than those used in SRTM and RAMP. For example, airborne synthetic aperture radar (SAR) interferometry has demonstrated the capability to acquire DEMs with 5 meter postings, 1 cm vertical resolution, and 2 m vertical accuracies, in addition to an orthorectified radar backscatter image at 2.5 meter postings; compare this with the 60m x 90m posting available currently and no associated orthoimagery. That is, for the price of an Arctic DEM, we would also get a picture of the Arctic at 2.5 meter resolution, and this picture can be merged with color Landsat to create stunning orthorectified images. These SAR systems, flying on a LearJet, can rapidly acquire day or night in a wide range of weather, eliminating most of the logistical delays common to other systems. Airborne Lidar, a laser based system, is also advanced to the stage where near-shore coastal bathymetry can be measured, such that we could seamlessly integrate DEMs and bathymetry. While the price of such acquisitions is high, it is comparable to DEM acquisitions on the rest of the planet and Mars, and the benefits would be enormous to a wide variety of polar researchers - perfect for the IPY. Presented in this poster will be several examples of how new DEMs have improved our Arctic research at UAF. McCall Glacier was originally an IGY field site and now has the longest record of mass balance observations of any glacier in the US Arctic, but our measurement program is hampered by the lack of decent topographic maps there. Our research using a new DEM in the Kuparuk River watershed in Alaska has shown that these DEMs substantially improve our hydrological modeling in such low gradient watersheds. With DEMs of such high accuracy and resolution, we can also begin a program of repeat-topographic mapping, to document changes not only to glaciers, but subtler permafrost phenomena with decimeter-scale changes such as pingos, thermokarsts, polygons, and oriented lakes. The time to acquire such data is now, however, before widespread changes occur. Thus the upcoming IPY can perhaps leave no better legacy than to replace the IGY-era, mediocre topographic maps with an accurate, high-resolution digital elevation model representing today's Arctic, which will remain valuable to generations of polar scientists.
DE: 0933 Remote sensing
DE: 1640 Remote sensing
DE: 1709 Geodesy
DE: 1848 Networks
DE: 9315 Arctic region
SC: Cryosphere [C]
MN: 2003 Fall Meeting