In situ observed relationships between skin temperatures and 2 m air temperatures in the Arctic

To facilitate the combined use of traditional 2 m air temperature (T2m) observations from weather stations in the Arctic and skin temperature (Tskin) observations from satellites the relationship between high latitude snow and ice Tskin and T2m is quantified. Multiyear data records of simultaneous Tskin and T2m from 20 different in situ sites have been analysed, covering the Greenland Ice Sheet (GrIS), sea ice in the Arctic Ocean, and coastal snow covered land in North Alaska. The diurnal and seasonal temperature variabilities and the impacts from clouds and wind on the T2m-Tskin differences are quantified. Considering all stations, T2m is on average 1.37 °C warmer than Tskin, with the largest differences at the GrIS stations (mean of diff. of 1.64 °C). Tskin and T2m are often highly correlated, and the two temperatures are almost identical (−1, likely due to the katabatic winds, which are most prominent at this wind speed. Clouds tend to reduce the vertical temperature gradient, by warming the surface, resulting in a mean T2m-Tskin difference of 0.53 °C considering all stations. Following that the influence of clouds on Tskin has been assessed by comparing clear-sky Tskin observations with all-sky observations averaged for the time windows of: 24 h, 72 h and 1 month. The largest clear-sky biases are generally found when 1 month averages are used and smallest for 24 h. The mean clear-sky bias for the 24 h average is −0.28 °C, ranging from −0.10 °C in summer to −0.95 °C in winter. The expected clear-sky biases and the difference between Tskin and T2m are of practical value for researchers and operational users that aim at integrating satellite observations with ocean, sea-ice or atmospheric models.