阿拉善高原近40a总云量变化特征分析

Analysis on Total Cloud Variation Characteristics in Alxa Recent 40 Years

利用阿拉善高原近40a（1971-2010年）观测年及四季平均总云量,分析其时空变化特征及Hurst指数,并对总云量与降水量、平均气温、日照时数及相对湿度等因子之间的关系进行分析.结果表明：（1）阿拉善高原近40a平均总云量在38.3％～45.8％之间;北部地区年平均总云量减少趋势显著,南部地区呈不明显的减少趋势.（2）年平均总云量与相对湿度呈显著正相关,与降水量、日照时数、平均气温相关不显著.春季、秋季和冬季总云量与降水、相对湿度呈显著正相关,与日照时数显著负相关,与平均气温相关性不显著.夏季总云量和降水量相关不显著,与相对湿度呈显著的正相关,与日照时数和平均气温呈显著的负相关.（3）Hurst指数分析显示,阿拉善高原北部地区年平均总云量、南部地区春季总云量、东北地区夏季总云量未来将显著减少,其余地区年及四季总云量的减少趋势不显著.

This paper used the mean total cloudiness in Alxa recent 40 years, analyzed its spatial and temporal variation characteristics and Hurst index, and researched the relationship that the total cloudiness and precipita- tion, average temperature, sunshine hours and relative humidity factor.The results showed：（1） The mean total cloudiness cover in the 38.3% - 45.8% in recent 40a;The average total cloudiness decreased significantly in northern, It was not obvious decreasing trend in southern. （2） The annual total cloudiness was positively con＇elat- ed with relative humidity, and precipitation, sunshine hours, average temperature is not significant. The total cloudiness and precipitation, relative humidity was positively correlated in spring, autumn and winter,and with the duration of sunshine, a significant negative correlation, and with the average temperature had no significant cor- relation. The total cloudiness and precipitation was not significant in summer, with the relative humidity is posi- tive correlation, with sunshine hours and average temperature is significant negative correlation. （3） according to Hurst index, the annual mean total cloudiness covered in northern, the total cloudiness in southern in spring, and the total cloudiness in summer in northeast would be significantly reduced.In addition,the total cloudiness de- creasing trend was not significant.