Extraction of Greenland Ice Sheet buried lakes using multi-source remote sensing data: With application to the Central West basin of Greenland

The Greenland Ice Sheet melts violently in summer, and supraglacial lakes appear in low-lying regions where the meltwater converges. The monitoring of supraglacial lakes is important as they play a key role in modulating the hydrological system and the Greenland Ice Sheet's mass balance. Recent studies show that numerous supraglacial lakes in the Greenland Ice Sheet do not refreeze completely in winter, but existing in the form of liquid water under snow or ice, which are referred as buried lakes. These buried lakes has the potential to impact the stability and mass balance of Greenland Ice Sheet. However, it is difficult to extract and analyse these buried lakes by using the visible images, because they exist under the surface of the Greenland Ice Sheet. In this study, we proposed a method to automatically extract the buried lakes by using both the Landsat8 and Sentinel-1 images. This method uses visible images to extract supraglacial lakes in summer to mask the SAR images, and then adopts the Rosin Threshold Segmentation Algorithm to extract buried lakes in the Central West basin of Greenland in the winter of 2018-2019. In addition, we analysed the distribution of these buried lakes by separating the water and ice based on the backscatter coefficient. We extracted the buried lakes in selected 10 test areas with our method and compared the results with those derived from visual interpretation. The results show that our method achieves good performance with the Kappa coefficient being up to 0. 85. Moreover, the area of supraglacial lakes is 102. 28 km(2) in the Central West basin of Greenland in summer of 2018. About 43. 09% of supraglacial lakes occurred in summer do not refreeze completely and becomes the buried lakes (44. 07 km(2)) in winter.