Comparison of Passive Microwave Melt Detection of Greenland: L-Band and XPGR

We examine melt over Greenland using two passive microwave-based melt detection algorithms. A recently developed L-band (1.4 GHz) liquid water quantification method, and a well known method based on 19 and 37 GHz brightness temperatures known as the cross polarization gradient ratio (XPGR). We discuss spatial patterns of total number of melt days, and temporal trends in total melt area. The L-band method provides quantified liquid water as opposed to melt flagging, but for this study we simplify the retrievals to a binary melt flag for the sake of comparison with the XPGR. We find similar spatial patterns between the two methods, but some notable differences such as melt on the Jacobsavn Isbrae is more apparent in the L-band retrievals as opposed to the XPGR.