我国总云量时空特征及其影响因素分析

目的分析中国总云量的时空分布特征、变化趋势及影响原因。方法利用全国360个地面站1951~2009年地面月总云量观测资料,采用线性倾向估计和相关分析方法。结果总云量最多区域位于西南和华南地区,最少位于北部干旱少雨地区。约35°N以北总云量从南到北随纬度增加带状分布减少,此纬度以南同纬度东部云量多于西部云量。20世纪90年代以及21世纪前10年总云量减少最明显。总云量减少最明显的区域位于东北、西藏西南部以及山东、安徽北部地区。大部分地区总云量与太阳黑子相对数、降水量、相对湿度、最大积雪深度之间存在显著正相关关系,蒸发量与总云量存在显著负相关关系。结论我国总云量总体上呈减少趋势,气候因素对总云量变化有重要影响。

Variation and influential factors of total cloud amount all over China

Objective-To analyze the spatio-temporal variation, trend and influential factors of to tal cloud cover in China. Methods-Based on 360 stations all over China during the period of 1951- 2009, using linear trend estimation and correlation analysis method are adopted. Results-The largest total cloud amount is located in Southwest China and South China while the least in the north part of China where there is rare rainfall. In the north of about 35°N, the total cloud amount locates decreases with the increase of latitude from the south to the north, and in the south of about 35°N, the cloud a mount at the same latitude in the east is more than that in the east. The total cloud amount reduced dramatically in the 1990s and the first decade of the 21st century. The obvious reduction in the total cloud amount appeared in Northeast China, southwest Tibet, Shandong and the northern region in Anhui. There is a significant positive correlation between the total cloud amount in most parts of Chi na and relative sunspot number, precipitation, relative humidity and maximum snow depth, while there is a significant negative correlation between the evaporation capacity and the total cloud cover.Conclusion-The total cloud amount shows a downward trend over the past 59 years. Climate factors have an important influence on the changes of total cloud cover.