## 2 Atmospheric Conditions of Zhongshan Station, East Antarctica
The lowest atmospheric pressure occurred on 11 April 2015 and the highest was on 18 July 2015 (Figure 1e). The short-term variations in wind speed, wind direction, air temperature, relative humidity and atmospheric pressure were considerable, which can prove the complexity of the weather conditions at Zhongshan Station. The multi-year average meteorological data are presented in Figure 2. The monthly average wind speed, radiation, day length, and air temperature in Figure 2 were obtained from the Atmospheric science data center of NASA. The monthly average wind speed from NASA and observed wind speed are shown in Figure 2a. The trend of wind speed from NASA is consistent with the observed results. For the multi-year average wind speed, the maximum and minimum wind speeds were 9.88 m/s in June and 7.5 m/s in January, respectively. The maximum and minimum monthly-observed wind speeds were 10.9 m/s in December and 4.8 m/s in February, respectively. The annual average wind speed from NASA was 9 m/s, which was similar to the annual observed result (9.78 m/s). The monthly average radiation and day length at Zhongshan Station are shown in Figure 2b. The radiation and day length decreased from January, and reached the minimum values at the same time (June). Then the radiation and day length continued to increase until December. The monthly mean radiation in May, June and July were 0.05 KW h/m\({}^{2}\)/day, 0.00 KW h/m\({}^{2}\)/day, 0.01 KW h/m\({}^{2}\)/day, respectively. Additionally, the monthly mean day lengths were 4.05 h, 0 h and 1.23 h, respectively. This phenomenon can indicate that polar night occurs from late May to late July in this region. The monthly mean radiation in January,  
Figure 1: Time series of hourly (**a**) wind speed, (**b**) wind direction, (**c**) air temperature, (**d**) relative humidity and (**e**) air pressure obtained by the manned weather station at Zhongshan Station, Antarctica. November, and December were 6.05 KW h/m\({}^{2}\)/day, 4.97 KW h/m\({}^{2}\)/day, 6.69 KW h/m\({}^{2}\)/day, respectively. The monthly mean day lengths in January, November, and December were 24 h, 20.8 h and 24 h, respectively, which polar day lasts from late November to early February of the following year at Zhongshan Station. As can be seen from Figure 2c, the monthly average air temperature at Zhongshan Station exhibited obvious seasonal characteristics. The average yearly air temperature was \(-\)19 \({}^{\circ}\)C. The maximum and minimum monthly mean air temperature was \(-\)7.13 \({}^{\circ}\)C in January and \(-\)27.3 \({}^{\circ}\)C in July. The weather condition of Zhongshan Station can be summarized as strong easterly winds, lower relative humidity, lower barometric pressure and cold air. The operating temperature range of the standalone renewable energy system in this study should be \(-\)50-30 \({}^{\circ}\)C based on the analysis of meteorological data at Zhongshan Station. Other meteorological elements should be taken into account during the design of the power supply system. Thus, in this study, the characteristics of power system at low temperatures should be considered and studied for achieve a long-term operation of research station in Antarctica.