L-band InSAR Estimates of Greenland Ice Sheet Accumulation Rates

Download or read book L-band InSAR Estimates of Greenland Ice Sheet Accumulation Rates written by Albert C. Chen and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Greenland Ice Sheet contains nearly 3 million cubic kilometers of glacial ice. Were the ice to completely melt, that would cause the sea level to rise about 7 meters. Each year, the ice sheet gains ice from snowfall and loses ice through iceberg calving and other ablation mechanisms. Thus assessing the ice sheet's mass balance (annual net gain/loss of ice) requires accurate spatial mapping of accumulation rates (mean annual snowfall). In this thesis, we examine how recent satellite radar remote sensing data can be used to supplement in-situ accumulation rate estimates in the inner regions of the Greenland Ice Sheet. We present a method using interferometric synthetic aperture radar (InSAR) data to obtain estimates of snow accumulation in Greenland. InSAR is a technique that provides images of the Earth from radar data collected by a spacecraft. We show that the second-order phase statistics (coherence) of InSAR images is related to subsurface structure, which, in the inner dry-snow zone of the Greenland ice sheet, is related to accumulation rate. We have implemented software to form and geocode InSAR images of Greenland and correct for ionospheric inhomogeneity, which has limited the accuracy of longer-wavelength measurements of the Earth's polar regions. We developed a model to relate accumulation rate to InSAR measurements. By inverting the model we obtain estimates of Greenland ice sheet accumulation rates. We show a comparison of our results with in-situ measurements over a 1,400 km strip spanning the entire dry-snow zone, and demonstrate that they follow the in-situ measurements more accurately than state-of-the-art results derived from radar amplitude measurements alone.