遥感降水产品在澜沧江流域径流模拟中的适用性研究

以澜沧江流域为研究区域，基于实测降水数据，从日尺度、月尺度到年尺度分别评价了TRMM 3B42 V7、CMORPH CRT、TRMM 3B42 RT、PERSIANN 4种遥感降水产品在格网尺度上的精度，并用实测降水数据和筛选出的精度较高的遥感降水产品驱动SWAT模型进行了径流模拟，以进一步探究遥感降水产品在澜沧江流域的适用性。结果表明：4种遥感降水产品在日尺度上精度都不高，与实测降水的相关系数都低于0.5。从整体看，TRMM 3B42 V7精度最高，月、年尺度下与实测降水的相关系数依次为0.95、0.90，CMORPH CRT精度稍低于TRMM 3B42 V7，其在月、年尺度下与实测降水的相关系数依次为0.89、0.77，TRMM 3B42 RT和PERSIANN精度较差，两者在不同时间尺度下与实测降水的相关系数都较低，基本都维持在0.5以下；径流模拟结果发现TRMM 3B42 V7和CMORPH CRT两种遥感降水产品对流域出口断面日、月径流模拟的能力均不如实测降水，但整体上三者都能够较好地反映出实测径流变化的趋势，三者径流模拟对应的纳西效率系数NS在0.65~0.94范围内；从纳西效率系数NS看，三者对应的数值相差幅度极小，从多年平均径流RE看，三者都表现出低估的情形，但与前两者（低估值在 -4%~-10% 范围内）相比，CMORPH CRT（低估值在 -10%~-20% 范围内）低估的幅度较大；TRMM 3B42 V7在整体上的径流模拟效果优于CMORPH CRT，在澜沧江流域具有更好的径流模拟适用性。

Application of Remote Sensing Precipitation Products in Runoff Simulation over the Lancang River Basin

Based on the observed rainfall data, the accuracy of four remote sensing precipitation products, such as TRMM 3B42 V7, CMORPH CRT, PERSIANN and TRMM 3B42 RT, were evaluated in the Lancang River Basin. The evaluation was performed at multiple time scales, ranging from daily to yearly, for the years from 2001 to 2014, but only one spatial scale: grid spatial scale. On the ground of observations and the selected high-accuracy products, the SWAT model was applied in runoff simulation to further explore the applicability of remote sensing precipitation products in the Lancang River Basin. The results show that four products present low accuracy on daily time scale, and their correlation coefficients（R) with observed rainfall data are less than 0.5; as a whole, TRMM 3B42V7 is the most accurate dataset with R being 0.95, 0.90, from monthly to yearly time scale, respectively; the accuracy of CMORPH CRT is slightly lower than that of TRMM 3B42 V7, with R being 0.89, 0.77, from monthly to yearly time scale, respectively; TRMM 3B42 RT and PERSIANN have present poor accuracy, and their R in different time scales are relatively low, with R basically maintaining below 0.5. The runoff simulation results show that the skills of TRMM 3B42 V7 and CMORPH CRT are not as good as that of the observed rainfall data on simulating the daily and monthly runoff of the river basin outlet section, but all three can better reflect the variation trend of measured runoff in runoff simulation with the corresponding Nash-Sutcliffe coefficient（NS) of the three keeping within the range of 0.65-0.94. From the perspective of the NS, the value difference of the three is insignificant. From the perspective of relative error of water quantity（RE), all of them underestimate water quantity , but the RE value of CMORPH CRT（within the range of -10%—-20%) is larger than that of the other two（ within the range of -4%—-10%). Overall, the runoff simulation capability of TRMM 3B42 V7 is better than that of CMORPH CRT in the Lancang River Basin.