Impacts of snow accumulation on air temperature measured by automatic weather stations on the Antarctic ice sheet

The heights of automatic weather station (AWS) sensors over the Antarctic ice sheet are nominal and change with snow accumulation or ablation.Therefore,the measured data may not be used directly.In this study,we analyzed the impact of snow accumulation on AWS observations using continuous measurements from three AWS that were deployed on the traverse route from the Zhongshan Station to Dome A over East Antarctica.We then corrected the measured air temperature to account for changes in the sensor height relative to the snow surface to improve the authenticity and representativeness of the observation data from the AWS.The results show that (i) the annual mean snow accumulations at Dome A,Eagle and LGB69 were approximately 0.11 m,0.30 m and 0.49 m,respectively,and the corresponding annual mean air temperature differences between the corrected and measured values at 1 m in height were 0.34℃,0.29℃ and 0.35℃;(ii) the impact on air temperature from accumulation decreases with height from the surface;(iii) the air temperature difference between the corrected and measured values was not directly proportional to the snow accumulation but was related to the seasonal air temperature variations and the intensity of the local surface inversion;and (iv) the averaged corrected air temperature was higher than the measured values except during the summer when there were days without temperature inversion.The magnitude of the temperature difference between the corrected and measured was mainly determined by snow accumulation and the intensity of the local surface inversion.