宁夏夏季各月降水的时空分布及与74类大气环流指数的关系初探

使用EOF方法,对宁夏全境具有代表性的19个气象观测站的1961～2008年夏季各月降水资料进行了时空分解,得到了夏季各月降水的EOF空间分布特征和时间系数变化趋势。利用国家气候中心资料室提供的1961～2008年共48年的74类月大气环流指数资料,对大气环流指数与宁夏夏季各月降水量之间的相关性进行了分析,得出了相关指数因子。利用最优子集回归方法(OSR)从相关因子中筛选出了最能拟合各月降水的4个关键因子,建立了最优子集回归预报方程,对1962～2008年共47年的夏季各月降水距平进行了回报,得出了各观测站夏季各月的历史拟合率。

Time-Spatial Distribution of Monthly Precipitation in Summer and Their Relationships with 74 Atmospheric Circulation Exponentials in Ningxia

Based on the monthly precipitation data provided by 19 meteorological stations in summer during 1961～2008 in Ningxia,the temporal and spatial distribution characteristics of monthly precipitation in summer were analyzed by EOF method.The results indicated that there was an obvious spatial difference in summer precipitation over the studied area.By using 74 atmospheric circulation exponentials data provided by National Climate Center of China,the correlations between atmospheric circulation exponentials and monthly summer precipitation in Ningxia were analyzed,and the related factors were selected.Four key factors which could simulate the monthly precipitation best were screened out from the above-mentioned related factors by OSR method,OSR equation with four key factors was built,it was used to simulate the historical monthly precipitation in summer during 1962～2008,and the historical coincident rates of simulating monthly summer precipitation at 19 meteorological stations were obtained.