Estimating Snow Accumulation From Insar Correlation Observations

Download or read book Estimating Snow Accumulation from InSAR Correlation Observations written by Shadi Oveisgharan and published by . This book was released on 2007 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: Snow accumulation in remote regions such as Greenland and Antarctica is a key factor for estimating Earth's ice mass balance. In situ data are sparse, hence it is useful to derive snow accumulation from remote sensing observations, such as from microwave thermal emission and from radar brightness. These data are usually interpreted using electromagnetic models in which volume scattering is the dominant mechanism. The main limitation of this approach is that microwave brightness is not well-related to backscatter if the ice sheet is layered. Because larger grain size and thicker annual layers both increase radar image brightness, the first corresponding to lower accumulation rate and the second to higher accumulation rate, models of radar brightness alone cannot accurately reflect accumulation. Consideration of interferometric radar correlation measurements also can resolve this ambiguity. Here we introduce an ice scattering model that relates InSAR correlation and radar brightness to both ice grain size and hoar layer spacing in the dry snow zone of Greenland. We use this model and ERS satellite radar observations to derive several parameters related to snow accumulation rates in a small area in the dry snow zone. These parameters show agreement with four in situ core accumulation rate measurements in this area, while models using only radar brightness data do not match the observed variation in accumulation rates.