Hybrid probabilistic forecast scheme for postfrontal shower precipitation

额后阵雨降水混合概率预报方案

• 批准号: 5426419
• 负责人: Professor Dr. Thomas Hauf
• 金额: --
• 依托单位: Institut für Meteorologie und Klimatologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2004
• 资助国家: 德国
• 起止时间: 2003-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5426419?language=en
• 关键词: Hybrid; probabilistic; forecast; scheme; postfrontal

A hybrid forecasting scheme for post-frontal convective shower precipitation is proposed. The deterministic forecast of the post-frontal convective precipitation field is combined with a probabilistic precipitation forecast for the individual rain areas contained therein. The rationale for this approach is the observation that ensembles of convective rain areas (CRAs) are in statistical equilibrium with synoptic scale conditions. Their characteristics follow simple universal laws, remain constant, if properly scaled and follow seif-similar distributions as was shown by THEUSNER AND HAUF (2003). The statistical properties are homogeneously distributed within Germany, except for the Alps and the coastal zone. Furthermore, individual rain areas seem to move more or less in a uniform matter given by the synoptic flow. The hybrid scheme forecasts statistical means of: number of CRAs, total rain area, areal precipitation, maximum local precipitation, rain duration; furthermore the local precipitation likelihood and other statistical quantities. Essential part of the work are (i) the extension of own previous work to include for rainfall rates based an common radar-reflectivity relationships, and (ii) the investigation of synoptic influence an the statistical properties, including the sampling errors. The scheure will be tested and evaluated following the methods proposed by KIRK AND FRAEDRICH (1998).

提出了一种锋后对流阵雨降水的混合预报方案。锋后对流降水场的确定性预报与其中包含的个别雨区的概率降水预报相结合。这种方法的基本原理是观察到对流雨区的集合与天气尺度条件在统计上是平衡的。它们的特征遵循简单的普遍规律，如果适当缩放，保持不变，并遵循Theusner和Hauf(2003)所显示的自相似分布。除阿尔卑斯山和海岸带外，统计特性在德国境内分布均匀。此外，个别雨区似乎或多或少地在天气气流给出的均匀物质中移动。该混合方案预报CRA个数、总雨量、面雨量、最大局地降水量、降雨持续时间等统计平均值，并进一步预报局地降水概率等统计量。这项工作的基本部分是：(1)扩展自己以前的工作，以包括基于共同雷达-反射率关系的降雨率，以及(2)调查天气影响和统计特性，包括抽样误差。该方案将按照Kirk和Fraedrich(1998)提出的方法进行测试和评估。