TRMM降水数据在洞庭湖流域的精度评估和应用

Accuracy Evaluation and Application of the TRMM Precipitation Data in Dongting Lake Basin

高分辨率卫星降雨产品的出现为降水观测提供了良好的前景。然而这些产品在使用前需要经过全面的精度评估。评估了TRMM (Tropical Rainfall Measuring Mission)3B43V7降水数据在洞庭湖流域的精度和适应性。基于洞庭湖流域1998—2011年TRMM降水数据和27个气象站点的实测降水数据,采用相关系数、均方根误差和均方误差技能分数等指标在月和季尺度下评估其在流域内精度,揭示各指标的空间分布特征。结果表明:(1)在月尺度上,TRMM数据与实测数据拟合良好,相关系数为0.89,但TRMM数据在流域大部分地区高估降水。(2)在季尺度上,TRMM数据精度较月尺度有所提升,相关系数达到0.94,并且可靠性更高。(3)两种数据在流域降水时空分布上表现出一致性,在春夏两季为湿润多雨期,秋冬季节降水则相对匮乏。流域内降水分布不均匀,整体呈从东南向西北减少趋势。

The high-resolution satellite rainfall products provide a great opportunity to monitor precipitation. However, the accuracies of these products need assessment before use. The objective of this study is to evaluate the accuracies and adaptabilities of the application of TRMM(Tropical Rainfall Measuring Mission) 3 B43 V7 data in the Dongting Lake Basin. The TRMM data and 27 meteorological precipitation data in the Dongting Lake Basin were collected from 1998 to 2011. The indices including correlation coefficient(r), root-mean-square error(RMSE) and mean square skill score(MSSS) were used to assess the accuracy of the TRMM data at the monthly and seasonal scales, respectively, within the basin, and the spatial distribution characteristics of each index was investigated. The results showed that:(1) on the monthly scale, the TRMM data had a good fit with the observed precipitation data with the correlation coefficient of 0.89;overall, the TRMM data was higher than that of the observed precipitation data in most areas of the basin;(2) at the seasonal scale, the TRMM data were comparatively more accurate with the correlation coefficient of 0.94, and the reliability was higher;(3) the temporal distributions of the two kinds of data were similar in the Dongting Lake Basin, the precipitation was higher in spring and summer while it was lower in autumn and winter. The distribution of precipitation is uneven in the Dongting Lake Basin, which reduces from the southeast to the northwest.