太阳辐射日变化对R15L9气候模拟效果的影响

THE SPATIAL AND TEMPORAL VARIATIONFEATURES OF PRECIPITATION ANOMALYDURING LATE SPRING AND EARLYSUMMER OVER NORTHWEST CHINA

利用菱形截断１５波９层全球谱模式做了有、无太阳辐射日变化的对比试验，分析了模拟的平均海平面气压、５００ｈＰａ高度、地表温度和降水的１月和７月气候场，并利用统计方法做了显著性检验。结果表明：太阳辐射日变化对气候模拟有显著的影响，尤其表现在北半球和陆地上。而当忽略日变化这种物理过程时，势必影响气候模拟的效果，产生系统误差。

The precipitation data at 90 observational stations from 1960 to 1990 are used to analyse the spatial anomaly features and time evolution rule and the mechanism in May and June over Northwest China by EOF and REOF methods. The results show that the main anomaly structures of rainfall in May and June over Northwest China present pluvial pattern or dry pattern in all the areas, and spatial changes are opposite pattern from the north to the south and the west to the east. The principal anomaly sensitive areas are the east of Northwest China,the Hexi Corridor, the east of Qinghai-Xizang Plateau, the north Xingjiang, the source areas of the Yangtze River and the Yellow River and the desert basin. The basic trend of the rainfall from 1951 to 1995 is that the precipitation in the east of Northwest China, the north Xingjiang and the source areas had a wet—dry—wet process, while an increasing trend of rainfall appeares in the Hexi Corridor, the east of Qinghai-Xizang Plateau and the desert basin areas. In the aspect of the atmospheric circulation, when the structures of 500hPa geopotential height departure field emerge evident positive PNA and negative EU patterns in May, the rainfall is below the average over Northwest China at the same time. When sensible heat increases over Qinghai-Xizang Plateau in spring, the precipitation amount increases during late spring and early summer.