降水的统计降尺度预报及其空间相关性和时间连续性重建
投稿时间: 2016-10-10  最后修改时间: 2016-10-10  点此下载全文
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作者单位E-mail
智协飞 南京信息工程大学 zhi@nuist.edu.cn 
基金项目:深圳南方强天气研究重点实验室项目(SZQX2015162);中国气象局公共气象服务中心委托项目“基于统计降尺度的多模式精细化预报系统”;江苏高校优势学科建设工程资助项目(PAPD)
中文摘要:利用TIGGE资料中欧洲中期天气预报中心(ECMWF)、日本气象厅(JMA)、美国国家环境预报中心(NCEP)以及英国气象局(UKMO)四个中心1-7天预报时效的日累计降水量集合预报资料,并以中国降水融合产品作为“观测值”,对我国地面降水量进行统计降尺度处理以及空间相关性和时间连续性的重建。在对降水量进行分级后,建立各个量级的回归方程进行降尺度订正,并利用Schaake Shuffle方法重建由于统计方法的使用而丢失的空间相关性和时间连续性。结果表明,分级回归相比未分级回归后的预报结果的相关系数更高,预报误差更小,更接近观测值,且Schaake Shuffle方法可以使预报结果的空间相关性和时间连续性更接近实况,集合成员间的相关性更集中。
中文关键词:降水量预报  统计降尺度  Schaake Shuffle方法  相关性重建
 
Statistical downscaling forecast and reconstruction of space–time correlation in the precipitation field
Abstract:Based on the ensemble forecasts of 1-7 day daily accumulated precipitation from the European Centre for Medium-Range Weather Forecasts (ECMWF), the Japan Meteorological Agency (JMA), the National Centers for Environmental Prediction (NCEP) and the UK Met Office (UKMO) in the TIGGE datasets, and the hourly merged precipitation product over China as the observed data, a forecast study on daily precipitation in China by means of statistical downscaling and a reconstruction of space–time variability in precipitation field have been conducted. Firstly, the statistical downscaling by constructing different regression equations according to different levels of rainfall was used to improve the precipitation forecast. Then a method called Schaake Shuffle was applied to reconstruct the spatial variability and temporal persistence lost in the process of using statistical methods. The results show that the forecasts after the regression according to different levels of rainfall are more accurate than the ones after the direct regression, because the anomaly correlation coefficient is bigger and the root mean square error is smaller. The spatial and temporal correlations from the reconstruction methodology are closer to observed correlations than the raw result. The deviation of correlation between ensembles decreased to some extent.
keywords:precipitation forecast  statistical downscaling  Schaake Shuffle method  correlation reconstruction
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