ECMWF、日本高分辨率模式降水预报能力的对比分析

Comparative Analysis of Precipitation Forecasting Capabilities of ECMWF and Japan High-Resolution Models

利用2012年4月1日至2013年3月31日ECMWF、日本高分辨率模式降水预报资料,全国2419个台站逐6 h降水量观测、CMORPH(NOAA Climate Prediction Center Morphing Method)卫星与全国3万余个自动站逐小时降水融合资料,基于列联表预报评分、泰勒图等统计方法,客观对比分析ECMWF、日本高分辨率模式对中国逐6、12和24 h分段降水的预报能力,主要结论如下:(1)整体来说,ECMWF对降水的预报优于日本模式,日本模式预报离散度偏大,而ECMWF预报相对平稳,与观测更加一致;(2)两个模式晴雨预报中降水发生频率较实际偏高,暴雨预报频率较实际偏低,随着分段间隔的增加,这一情况有所改善;(3)ECMWF模式6 h分段降水晴雨预报评分低于日本模式,暴雨预报评分整体高于日本模式,12和24 h分段ECMWF模式晴雨、暴雨预报评分一致高于日本模式;(4)通过调整阈值改变预报偏差能够在一定程度上提高预报技巧;(5)就空间分布来看,模式在东南地区Bias、CSI技巧评分整体优于西北地区。

By using precipitation data collected every six hours by 2419 stations from April 1 to March 31 in 2013, precipitation forecast data of ECMWF and Japan high resolution model, and hourly rainfall data fusion by CMORPH （NOAA Climate Prediction Center Morphing Method） satellites and more than 30 thousand automatic stations based on contingency table and Taylor diagram statistical method, the precipitation forecasting capabilites of ECMWF and Japan high-resolution model by every 6 h, 12 h, 24 h segment are comparatively analysed. The results show that： （1） Generally, ECMWF has an advantage over Japan high-resolution model whose forecast dispersion is a bit larger. However, the forecast of ECMWF is relative steady, agreeing more with the observation. （2） The precipitation frequency predicted in weather forecasting by the two models is higher than the real case while the forecast of rainstorm frequency is lower than it. However as piecewise intervals increase, this situation is improved. （3） The 6 h fractional precipitation weather forecast score by ECMWF is lower than by the Japan model while the 12 h and 24 h fractional precipitation weather forecast scores of ECMWF are higher than those of Japan model, but its rainstorm forecastscores are all higher than those Of the Japan model. （4） By changing forecast bias using threshold adjustment, the forecasting skill scores are improved to some extent. （5） Regarding the spatial distribution, the model can forecast precipitation more reasonably in coastal areas than in the northwestern area.