500hPa月平均高度场球函数谱异常与陕西旱涝的关系

使用NCEP/NCAR再分析资料中的 50 0hPa月平均高度场资料及其主要球函数系数和陕西测站月降水量资料 ,结合陕西分区春、夏季旱涝长期预报的实际问题 ,探讨半球月平均 50 0hPa月平均高度场的球函数系数资料在长期天气预报中的应用的途径。发现基于区域降水指数 (IR)定义的陕西区域春、夏季旱涝指数I与历史实况相符 ,而球函数系数的年际异常具有低维、低阶特性 ,可以利用它们作为预报量、预报因子的参数 ;对春、夏季旱涝指数与同期和前期环流异常的相关分析表明 ,北半球环流异常与陕西各区春、夏旱涝的出现相关联系显著 ,南半球环流异常与陕西春、夏旱涝出现的相关联系总体上不显著。

Relationship between Spectrum Anomaly of Global 500hPa Monthly Mean Height Field and Flood/Drought in Shaanxi

An attempt to explore an application of spherical function coefficient data of 500hPa monthly mean height field in flood/drought prediction, it shows the sectorized flood/drought index I in spring and summer of Shaanxi, with being defined on the basis of sectorized precipitation index(I R)and historical record, the inter-annual anomaly of spherical function coefficients of low dimension and low order are obtained, they can be used as parameters in actual prediction. Based on the analysis of synchronous and time-lagged correlation of the flood/drought index and circulation anomaly, it is found that the relation between the Northern Hemispheric circulation anomaly and flood/drought of Shaanxi is statistically significant while the relation between the Southern Hemispheric circulation anomaly and flood/drought of Shaanxi is not significant.