Satellite thermal mapping of the lowest surface temperatures in Greenland

Inspired by a recent paper on the lowest observed air temperature in thenorthern hemisphere (AWS observation near Summit Station; Weidner et al., 2021),we will composite Aqua MODIS Land Surface Temperatures (LST, data setMYD11_I2 ver061) over the Greenland Ice Sheet spanning 2003-2023. Our preliminaryanalysis shows LST below 200°K with just part of the data processed. or colderthan -100°F. Using the record-setting AWS station data, we estimate thetemperature inversion between the ~2 meter air temperature and the snow surfaceto adjust the LST satellite measurements.  Greenland shows a similar gradient intemperature between LST ‘skin’ temperature and air temperatures as seen inAntarctica from our earlier research (Scambos et al., 2018).  Lowesttemperatures occur on clear-sky polar nights under calm or nearly calm winds,in general just to the west and northwest of the ice divide. Maps of LST showsmall scale geographic variations that are closely associated with local lows intopography. We infer that this is a result of cold air pooling and furtherchilling of the surface under conditions that maximize radiative heat loss.