Hybrid probabilistic forecast scheme for postfrontal shower precipitation

提出了一种锋后对流阵雨降水混合预报方案。将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测到对流雨区（CRAs）的集合与天气尺度条件处于统计平衡。它们的特征遵循简单的普遍规律，如果适当缩放并遵循自相似分布，则保持不变，正如THEUSNER和HAUF（2003）所示。除阿尔卑斯山和沿海地区外，德国境内的统计特性分布均匀。此外，个别雨区似乎或多或少地在天气流给出的均匀物质中移动。混合方案预报的统计方法有：暴雨点数、总降雨面积、面降水量、局地最大降水量、雨时；此外，当地降水可能性和其他统计量。工作的基本部分是(i)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（ii）调查天气影响和统计特性，包括抽样误差。该计划将按照KIRK和FRAEDRICH（1998）提出的方法进行测试和评估。

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).