Local-scale snow accumulation variability on the Greenland ice sheet from ground-penetrating radar (GPR).

摘要

Measurements of snow accumulation are critical to studies of mass balance. Traditional point measurement techniques (snow pits, manual probes, firn and ice cores) are limited in space and often do not represent the region surrounding them due to spatial variability that is caused by a variety of factors, including surface slope and deposition and erosion by wind. Current accumulation maps of Greenland are based on point measurements and have estimated errors of 20-25% (Bales et al., 2001; Ohmura and Reeh, 1991). Ground-penetrating radar (GPR) has the potential to significantly improve upon these accumulation estimates because of its ability to cover large regions over short time periods with relative ease at high vertical (depth) and horizontal (areal) resolutions. The current study employs GPR data to investigate the distribution and variability of accumulation at shallow depths (∼5 m) and at the local scale (100-m by 100-m) at two locations on the Greenland ice sheet (Tunu-N and NASA-U). Beyond providing a better understanding of local-scale snow accumulation patterns on the Greenland ice sheet, the results that will be discussed also have potential implications for the interpretation and selection of ice cores as well as for space-borne remote sensing techniques aimed at deriving snow water equivalent (SWE) from passive-microwave and/or scatterometry.*; *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation).