近60年中国地区云的时空分布特征

Temporal and Spatial Distributions of Cloud in China Region in Recent 60 Years

摘要: 利用中国地区756个测站1951~2010年地面观测总云量和云状的定时值资料，分析了中国地区总云量、云状的时空分布以及变化趋势等特征。结果表明：中国地区年平均总云量分布呈“南多北少”型，四川东部、贵州中西部是多云中心；高云频率分布呈“南低北高”的特点，而低云则为“南高北低”型，中云频率的高、低值中心都位于我国南方；云量和云状变化具有明显的季节特征，由冬到春，云量增加，云状频率增大，由春到夏，云量继续增加，频率进一步增大，而由夏到秋，云量减少，频率减小；年平均总云量在中国大部分地区呈减少趋势。

Abstract: The characteristics such as temporal and spatial distributions, variation tendency of total cloud cover and cloud form are analyzed, using the hourly cloud data at 756 observation stations in China region during the period from 1951 to 2010. The results show that the annual mean of total cloud cover is excessive in south and few in north, also most in east Sichuan and midwest Guizhou. It can be also found that the frequency of high cloud is low in south and high in north. But the opposite is existent about the frequency of low cloud. And the highest and lowest frequency of middle cloud appears in south. Additionally, the cloud cover and cloud form have obvious seasonal variations. From winter to spring, the cloud cover increases, with the increasing of the frequency of cloud form. And it continues to increase from summer to spring, with the further increasing of the frequency of cloud form. But it reduces from summer to autumn, with the reducing of the frequency of cloud form. At the same time, the total cloud cover decreases in the 60 years.