TRMM降水数据在横断山区的精度

The Accuracy of TRMM Precipitation Data in Hengduan Mountainous Region, China

利用相关系数法和散点斜率法对横断山区1998—2011年之间月尺度的TRMM3843降水数据精度进行了检验。研究表明，TRMM3843降水数据与实测数据相关性很强，但是比实测降水量偏大33．9％。在横断山北部大雪山以东地区和南部香格里一贡山一德钦一带三江并流区TRMM3843数据误差较大。各个季节TRMM3843降水与实测值误差的空间分布有较大区别，但是都表现为北部沿经向分布，南部沿纬向分布的趋势；横断山区高海拔地区气象站点稀少和复杂的下垫面环境是产生观测误差的主要原因。

Based on the correlation coefficients and scatter points slope methods, the accuracy of TRMM 3B43 data at monthly time scale during 1998-2011 was validated using 24 meteorological stations data, with the meth- od of Kriging under ArcGIS, the error spatial distribution map of TRMM 3B43 data was drawn in order to re- search the regional difference. There was a strong correlation between TRMM 3B43 data and meteorological sta- tions observation data（R=0.928; p〈0.01）, but the value of TRMM 3B43 precipitation was greater than meteoro- logical station, the deviations were 32.0%（spring）, 38.3%（summer）, 36.8%（autumn）, 34.9%（winter）, respective- ly. The TRMM 3B43 data was accurate in the south and the northwest, while the northeast and middle area was poor, especially in east Mt. Daxue and three Parallel Rivers area, the deviation is greater than 35% in east Mt. Daxue and three Parallel Rivers area and 25%-35% in other areas. The error spatial distribution of TRMM 3B43 precipitation is quite different, but most distribution follows a basic structure that distributed along the longitude in north of Hengduan Mountains and along latitude in south. The meteorological stations in Hengduan Moun- tainous Region are spaced widely and distributed unevenly. The terrain is complicated and varied in the study ar- ea, the longitudinal range-gorge caused an obvious action that east and west blocked but north and south through, which impacted on the spatial distribution of southwest monsoon obviously, and the southwest mon- soon is the crucial factor which influenced the precipitation of Hengduan Mountainous Region. In spring and summer, the precipitation spatial and temporal distribution is discontinuous because of range-gorge terrain. In autumn and winter, the precipitation equivalent area distributed continuously, the influence of terrain is not obvi- ous. The main error sources of the meteorological stations are of scarcity at high elevation and the mountain ter- rain special surface.