淮河流域TRMM多源卫星降水产品精度评估

Accuracy Evaluation of TRMM-based Multi-satellite Precipitation in Huai River Basin

不同的地区卫星降水产品的预报能力差别较大,因此需对卫星降水产品进行精度评估。基于淮河流域26个气象站的降水数据,采用统计方法评估了2001~2011年热带降水观测计划（TRMM）最新一代降水产品3B42V7和3B42RTV7在中国气候过渡带淮河流域的适用性。结果表明,两种降水产品均存在高估现象,3B42V7的性能优于3B42RTV7,两种产品夏季性能明显优于冬季;3B42V7与3B42RTV7年降水量几乎均高于地面观测年降水量,3B42RTV7年降水量的估算性能比3B42V7差,两种降水产品在湿润年的性能优于干旱年;除在小降水事件（0～1mm）发生概率明显低外,3B42RTV7、3B42V7与站点降水发生频次的趋势几乎一致,且全年优于汛期。降水强度〈25mm/d时,两种降水产品会高估降水量,对〉25mm/d的降水事件会低估,两种降水产品的趋势一致且相差不大;汛期3B42V7对降水强度〉25mm/d的降水事件拟合较好。与3B42RTV7相比,3B42V7有稍高的确报率、临界成功率及较低的错报率;TMPA产品对小雨或弱降水的确报率较高,对强降水尤其是25mm/d以上的降水错报率高达70%以上。

This study focuses on evaluating tropical rainfall measurement mission（TRMM）multi-satellite（TRMM3B42RTV7and TRMM 3B42V7）using an independent rain gauge network in Huaihe River in climatic transition zone of China.This gauge-based evaluation was performed by several critical statistical metrics at a range of temporal scales（from annual,seasonal to daily）from 2001 to 2011.Assessment results show that：3B42RTV7and 3B42V7 have an overestimation in the whole temporal scales and a better performance in summer than in winter;3B42V7generally exhibits better performance than 3B42RTV7.3B42RTV7 and 3B42V7overestimated the annual gauge observations;3B42V7has the lower error and relative bias than 3B42RTV7;the analysis indicates that 3B42RTV7 and 3B42V7perform better in wetter years than in dries years.3B42RTV7 and 3B42V7have higher occurrences than gauge observations,and they have similar distributions with gauge observations except underestimated the occurrence at low rain rates（1 mm/d）.3B42RTV7 and 3B42V7have more precipitation（except rain rates25mm/d）than gauge observation during the 11-year study period,and they have similar distributions at different rain rates.In summer,3B42V7 exhibits a relatively better degree of agreement to the gauges with gauges at high rainfall rates（25mm/d）.3B42V7 generally shows better scores for all the statistics with higher POD and CSI values and lower FAR than 3B42RTV7 at all rainfall thresholds both in the whole 11-year period and in summer.The TMPA products have higher POD values at lower rain rates and higher FAR at higher rain rates（25mm/d）.