HR: 0800h
AN: C31B-0319    [Abstracts]
TI: A New MODIS-based Mosaic of Antarctica: MOA
AU: * Bohlander, J
EM: jennb@nsidc.org
AF: National Snow and Ice Data Center, CIRES, University of Colorado, 449UCB, Boulder, CO 80309 United States
AU: Scambos, T
EM: teds@nsidc.org
AF: National Snow and Ice Data Center, CIRES, University of Colorado, 449UCB, Boulder, CO 80309 United States
AU: Haran, T
EM: tharan@nsidc.org
AF: National Snow and Ice Data Center, CIRES, University of Colorado, 449UCB, Boulder, CO 80309 United States
AU: Fahnestock, M
EM: mark.fahnestock@unh.edu
AF: Complex Systems Research Center, Institute for the Study of the Earth, Oceans, and Space, University of New Hampshire, 39 College Road, Durham, NH 03824 United States
AB: A digital image map of the Antarctic continent assembled from ~100 MODIS (Moderate Resolution Imaging Spectroradiometer)band 1 and band 2 orbit swaths is presented. The map is comprised of both Terra and Aqua MODIS images acquired during the 2003-2004 austral summer. Multiple images of all areas are combined in an image-enhancement scheme to provide surface resolutions between 125 and 250 meters. Images were destriped, georeferenced, and resampled using the MS2GT software available at NSIDC. Acquisition times were limited to 0500 - 1300 UT continent-wide to provide a more uniform illumination direction of ice surface morphology across image seams, while at the same time clearly image linear snow features of every orientation. Regions of cloud cover and intense forward scattering from snow were removed. Both channels are compiled and an approximate grain size algorithm is applied in a separate data layer. The mosaic is rendered in a 125-meter grid identical to the RAMP (Radarsat Antarctic Mapping Project) Antarctic Mapping Mission - 1 (AMM-1) 125-meter mosaic. The image map reveals a host of detailed features on the ice sheet, ice shelves and fast ice of the continent, and provides an accurate rendition of mountain and nunatak features. In particular, snow dune features, ice flowlines and streaklines, crevasse regions, and ice shelf rifts are imaged clearly. Mean grain size information was also extracted from an normalized difference of the band 1 and band 2 images, highlighting blue ice areas. The MOA image map is complimentary to the radar-image-based RAMP mosaic, highlighting true surface morphology without a subsurface volume backscattering component. This results in a better discrimination between accumulation- and crevasse-related subsurface changes and surface features.
DE: 9310 Antarctica
DE: 1824 Geomorphology (1625)
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting