中文摘要：

利用中山站1989-2011年极昼期间的气温、气压、风、降水等高质量的地面气象观测资料, 对中山站极昼期间气象要素基本气候特征和变化趋势进行了统计与分析, 研究了极昼期间天气特征. 结果表明： 极昼期间年平均气温为-0.6 ℃, 呈缓慢下降趋势, 其变化速率为-0.2 ℃·（10a）-1;年平均风速为5.4 m·s-1, 变化速率为-0.5 m·s-1·（10a）-1;共出现降水日数459 d, 占极昼期间总日数的33.3%;年平均日照时数为763.8 h, 日照时数呈上升趋势, 变化速率为26.8 h·（10a） -1. 研究结果有助于了解和研究南极中山站气候概况, 对中山站度夏科学考察工作有重要的参考价值.

英文摘要：

In this paper, the high quality surface meteorological data observed in Zhongshan Station during the polar day, 1989-2011, including air temperature, pressure, wind, precipitation, etc., are used to carry out some statistics and analysis for understanding the basic characteristics and variation trends of meteorological elements during the polar day at Zhongshan Station. Furthermore, the weather features during the polar day are summarized for understanding and analyzing the climate profile of Antarctica. It will be useful for Zhongshan Station summer scientific research. It is found that during the polar day, the annual average temperature is -0.6 ℃, with a changing rate of -0.2 ℃·（10a）-1, showing a slowly descend tendency. The annual average wind velocity is 5.4 m·s-1, with a changing rate of -0.5 m·s-1·（10a）-1. Totally there are 459 days of precipitation, accounting for 33.3% of the total days of the polar day;the annual average sunshine time is 763.8 h, with an increasing rate of 26.8 h·（10a） -1.