TRMM卫星降雨数据在湖南省的精度和可靠性评定

卫星降雨数据的高时空分辨率使其在洪涝灾害监测、流域水文模型模拟等方面得以广泛应用,而对卫星降雨数据的精度评定和可靠性分析仍然是当前重要的研究课题。采用中低纬度旱涝灾害频发的湖南省23个国家基准气象站的降雨数据作为地面验证数据,对最新一代TRMM卫星降雨产品(3B42V7)的精度和误差特征进行了全面评估。从日、月、年和季节的不同时间尺度以及空间分布和高程等不同的空间要素方面对比分析了1999-2012年该卫星降雨产品在湖南地区的适应情况。研究表明:TRMM卫星反演降雨数据在日尺度上与地面气象站数据的匹配情况较差,相关系数仅为0.31;而在月尺度上有显著提高,相关系数为0.88。在干旱季节(11、12、1、2月)的表现要优于湿润季节(5、6、7、8月)。3B42卫星反演降雨数据存在比较明显的空间变异性,空间要素如高程、位置分布等对卫星降雨数据可靠性的影响强于降雨量的影响。

Evaluation of accuracy and reliability of TRMM satellite precipitation data in Hunan Province

The high spatial-temporal resolution of satellite precipitation data can be widely used in flood disaster monitoring and hydrological modeling. The accuracy assessment and reliability analysis of the satellite precipitation data are still the important research issues. The paper overall evaluated the performance of TRMM satellite precipitation product 3B42V7 in Hunan Province by using the gauged precipitation data from 23 meteorological stations as the benchmark data. From the different time scales of daily, monthly, seasonal and annual,and different space elements such as spatial distribution and elevation,the paper compared and analyzed adaptation situation of satellite rainfall products from 1999 to 2012 in Hunan Province.The results show that the performance of satellite precipitation data on daily scale is not satisfactory, the correlation coefficient is only 0.31. But it goes to be much better on monthly scale with the correlation coefficient of 0.88. the annual rainfall from TRMM 3B42 can correlate well with the amount of rainfall on the ground of the region. The performance of satellite precipitation data in arid season (from November to February) is better than that in humid season (from May to August).Besides, the satellite precipitation data of 3B42 exists obvious spatial variability. The spatial factors such as elevation and spatial distribution have greater influence on the accuracy of satellite precipitation data than that of the amount of rainfall.