Abstract:

In this paper, different precipitation form data (rainfall days and snowfall days) were analyzed based on the observations of automatic weather stations at the Great Wall station (GW) and Zhongshan station (ZS) during 1985-2015 and 1989-2015, respectively. The relationship between surface air temperature, Amundsen Sea Low and different precipitation form in the station were also discussed. The results showed that the precipitation days at GW were more than at ZS. The annual total precipitation days, rainfall days and snowfall days showed increasing trends at GW. During 1985-2015, the number of annual total precipitation days, rainfall days and snowfall days at GW were 236-343 d, 74-185 d and 157-282 d, respectively, with an increasing trend of 4.51 d/10a, 2.68 d/10a and 1.25 d/10a, respectively. At ZS, where the snowfall was the main precipitation form, the annual total precipitation days showed a slight decrease (1.30 d/10a) during 1989-2015 (104-173 d). The temperature was positively correlated with the ratio between rainfall days and precipitation days, especially in the autumn Mar?May, the ratio between rainfall days and precipitation days had an increasing trend significantly (4.36%/10a). It is suggested that a warmer climate may be associated with higher fraction of precipitation falling as rain in the vicinity of GW. And the Amundsen Sea Low also has an impact on the precipitation form in GW. The eastward moving of Amundsen Sea Low in autumn leads to the warm, wet winds that blow to the Antarctic Peninsula stronger. It is conducive to the rainfall in GW.

Key words: Antarctica, Great Wall station, Zhongshan station, Precipitation form