多卫星遥感降水数据精度评价
Evaluating TRMM multi-satellite precipitation analysis using gauge precipitation and MODIS snow-cover products
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摘要: 利用中国650个台站降水数据,在日、月、年尺度上,分析了多卫星降水分析数据(TMPA3B42)在中国大陆50°N以南地区的适用性,并利用MODIS逐日积雪数据评估了冬季TMPA数据在以青藏高原为主体区的精度。结果表明:TMPA日降水数据精度存在时空不稳定性,且随着时间尺度的增加,TMPA降水数据的精度提高;在同一时间尺度上,TMPA数据精度在降水量大的地区要明显好于降水稀少地区,但年尺度降水大于2500mm地区存在明显低估;TMPA数据冬季区域降水空间误差平均水平在15%,当只考虑积雪区时的降水空间误差平均水平在40%,这说明TMPA对冬季降水空间量较差,但同时这也意味着可以利用MODIS积雪数据修正TMPA冬季降水数据。Abstract: The Tropical RainfallMeasuringMission(TRMM)Multi-satellite Precipitation Analysis(TMPA)3B 42 product is evaluated using the gaugeprecipitations from 650 weather stations across China at daily, monthly and annual tine steps.The TMPA-3B42 performance accuracy is also assessed using theModerate Resolution Inaging Spectroradiometer (MODIS) daily snow-cover product for the Tibetan Plateau region.Results show that TMPA-3B42 performs well at coarse temporal resolutions.However, less satisfactory result is obtained at the daily tine step.At the same temporal resolution, the humid region TMPA-3B42 performs better than the arid region ones.An exception is found for regionswith the annual precipitation excess the 2500 mm threshold.During winter, the average difference between the TMPA-3B42 product and the MODIS snow-coverproduct is only around 15% at a regional scale.However, the difference can be as high as 40% if only the region's snow covered areas are considered in the product comparison, which indicates that the TMPA-3B42 product is less skilful in winter.The MODIS snow-cover product can thus be used to improve the performance of TMPA-3B42.