Abstract
We present the results from two independent approaches for monitoring ice-sheet melt area over western Greenland. The microwave-based cross-polarization gradient ratio (XPGR) approach (Abdalati, W. and Steffen, K., 1995, Detecting ice-sheet melt area over western Greenland using MODIS and AMSR-E data for the summer periods of 2002-2006. Geophysical Research Letter, 22, pp. 787-790) is compared with a newly developed technique that exploits reflectance characteristics of snow/ice using near-infrared and visible wavelengths, to assess the extent of ice-sheet melt area over the west coast of Greenland. Data from the moderate resolution imaging spectroradiometer (MODIS) sensor onboard the National Aeronautics and Space Administration's (NASA) Earth Observing Satellite (EOS) Terra are analysed through the years 2002-2006 to monitor melt area extent between May and September. Concurrently, the XPGR ratio is derived from advanced microwave scanning radiometer (AMSR-E) data to develop a comparative measure of melt area over the same period of investigation. Although the techniques represent fundamentally different physical approaches, good agreement is observed between these distinct melt area products. The enhanced spatial resolution that is achieved from the MODIS sensor offers additional insight into the melt response over the course of the summer melt period and highlights the advantage of synthesizing diverse sensors and retrieval algorithms for Earth observation.