MOS方法在西北地区东部春季干旱预警中的应用与检验

Application and Test of the MOS Method to Spring Drought in the East Region of Northwest China

应用西北地区东部40个气象站1982—2005年3—5月逐月气象干旱综合指数(C_i指数)以及同期国家气候中心动力延伸预报1～30天的500 hPa平均高度场,利用MOS方法在数值预报产品释用方面作了应用及检验。结果表明:预报方程预测C_i指数的平均预测准确率仅为66%,但经过订正后,按40个站的序列分析,春季平均预测准确率上升为77%,平均准确率提高11%,3月幅度最大提高15%,5月幅度最小提高了8%,尤其是最小值提高的幅度最大,平均提高25%。

With the data of monthly meteorological drought integrated index（C_i） of 40 meteorological stations in the east region of Northwest China from March to May in 1982—2005 and the 500 hPa monthly mean geopotential height field in the corresponding period from the dynamical extended prediction provided by the National Climate Center,the application and test have been done by the MOS method in the aspect of explanation and reanalysis of numerical forecasting products.The result showed that the average accuracy to C_i predicted by the original equation was only 66%in spring,but the corrected average accuracy reached 77%,and increased by 11%according to sequence analysis of 40 stations,with a maximum rise of 15%in March,and a minimum rise of 8%in May.Particularly,the increment of the minimum value was the greatest with a 25%increment in average.