月动力延伸预报产品在西北地区月降水预测中的释用

利用西北地区较密的163个气象观测站点逐月降水资料、NCEP/NCAR再分析资料500 hPa逐月高度场和月动力延伸集合预报500 hPa高度场资料, 进行了气候预报、持续性预报、实况解释检验和月动力延伸预报产品释用预测试验的比较。结果表明:实况解释检验结果的准确率 (PS) 评分最高, 气候预报平均PS最低, 月动力延伸预报解释应用方法略低于实况解释检验, 高于气候预报和持续性预报。PS的空间分布表明, 月动力延伸预报解释应用结果和实况回报试验的分布非常相似, PS最大值分布在青海南部、陇南和陕西大部等各月降水气候值相对较大的地区, PS较小的地方则在新疆部分地区、甘肃河西西部等各月降水气候值相对较小的地区, 西北其他地区PS值相差不明显。此外, 利用密集站点资料进行解释应用的效果高于利用稀疏站点资料的结果, 表明更多观测信息的应用有利于改善预测技巧。

Interpretation of Monthly Dynamical Extended Range Forecast Products in Northwest China

Using monthly precipitation data of 163 observatory stations in Northwest China, reanalysis data of 500 hPa monthly average geopotential height from NCEP/NCAR,and monthly 500 hPa geopotential height of monthly dynamical extended range forecast,comparisons among the climatic forecast,persistence forecast,explanation test of reanalysis data,forecast experiment with the interpretation method of monthly dynamical extended range forecast products are made.The results show that the skill of the reanalysis data explanation test has the highest score,while the climatic forecast score is the lowest.The score of the interpretation method of monthly dynamical extended range forecast is a little lower than that of the interpretation test of reanalysis data,but higher than that of climatic forecast and persistence forecast.It indicates that by the spatial distribution of the PS score over Northwest China,the distribution of monthly dynamical extended range forecast is very similar with that of the analysis data of interpretation test.The regions with the highest PS score located in the south of Qinghai Province,south of Gansu Province and south of Shaanxi Province where the monthly precipitation climate value is relatively high.The regions with the lowest PS score locate in part of Xinjiang,west of Hexi of Gansu Province where the monthly precipitation climate value is relatively lower.And the downscaling tests show high skill when more data of observation stations are used.