降尺度方法在安徽省月降水量预测中的试用

Application test of downscaling method to monthly precipitation forecast in Anhui province

基于NCEP/NCAR 500 hPa高度场、T63月动力延伸预报500 hPa高度场和安徽省降水资料,依据动力预报产品释用方法中所建立的月降水距平百分率预报方程,从月和旬两种不同时间尺度以及固定资料和选择资料来反演方程系数共4种降尺度方法来预报安徽省20个代表站月降水。1995—2005年11 a的回报检验表明了4种方法都具有较好的预报能力,从旬时间尺度较月尺度来预报月降水具有优势,在汛期和汛期降水偏多年更为明显。

Based on 500 hPa geopotential height from NCEP/NCAR reanalysis data, 500 hPa height forecast obtained from T63L16 model, and Anhui province rainfall data, according to the monthly precipitation anomaly forecast equation, the forecast equation coefficients are calculated by immovable data and selected data from monthly and dekadly time scales, four downscaling methods have been used to forecast Anhui province 20 stations monthly precipitation. Eleven-year hindcast test proves that four methods have good forecasting skill, dekadly scale forecast of monthly precipitation is better than monthly scale, especially in flood season and the year when heavy rainfall happened in flood season.