近50年陕西黄土高原云量和气温年际变化

利用陕西黄土高原24个气象站1957年以来的气温、总云量和低云量观测资料,分析了它们的年际及年代际演变趋势及相关关系。结果表明:近50年区域年平均气温波动升高,尤其是1987年以后;北部风沙区气温的年际变化较大,增温幅度由北向南递减;1957年以来区域年平均总云量呈逐渐减少趋势,低云量下降趋势较总云量更为明显,2000年以后总云量有所增加。相关分析表明:陕西黄土高原年平均气温与年均总云量及低云量呈明显的负相关,均通过了0.001显著性水平检验,且低云量的相关更为显著;总云量和低云量与降水量呈显著正相关;不同区域和不同季节总云量和低云量与气温的相关系数有明显差异,但与降水量的相关非常显著。

Interannual Changes of Cloud Cover and Surface Air Temperature over Loess Plateau Region of Shaanxi Province in Recent 50 Years

The interannual and interdecadal changes of air temperature and the correlation with total-and low-cloud covers are analyzed,by means of the observed data of surface air temperature from 24 stations over the Loess Plateau region of Shaanxi in recent 50 years.The results indicate that mean temperature increased in a wavy way,especially after the 1987s;the interannual changes of air temperature in the northern sand-drifting areas were obvious,with the warming amplitudes decreasing from north to south;since 1957,the annual mean total cloud cover gradually decreased,and the decreasing tendency of low cloud cover was more obvious than that of the total,but the total cloud cover increased after 2000.The correlation analysis indicates that there was negative relation between annual mean air temperature and total and low cloud covers in the Loess Plateau region of Shaanxi,both passed the test with the significant level being 0.001 and the low cloud cover had more significant relation with temperature;there was obvious positive relation between precipitation and total and low cloud covers;meanwhile,the correlation coefficients between air temperature and total-and low-cloud covers were different greatly in different regions and seasons,but there was significant correlation between cloud cover and precipitation.