基于TRMM数据提取降雨侵蚀力的校正方法——以蓟运河上游地域为例  

Calibration of rainfall erosivity calculation based on TRMM data:A case study of the upriver basin of Jiyun River,North China

作　　者：靳秋桐 史明昌[1,2,3] 张举涛[1,2] 王珊 胡影 

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]北京林业大学水土保持与荒漠化防治教育部重点实验室,北京100083 [3]北京地拓科技有限责任公司,北京100084 [4]高德软件有限公司,北京102200

出　　处：《中国水土保持科学》2015年第4期94-102,共9页Science of Soil and Water Conservation

基　　金：林业公益性行业科研专项经费项目课题"基于生态安全的水土保持措施空间配置技术"(201404209)

摘　　要：由于TRMM数据的时间分辨率较低,导致用TRMM数据计算某一区域指定时间段内的降雨侵蚀力存在较大的系统误差。为解决该问题提出通过统计研究区气象站实际降雨过程的数据,或者通过模拟研究区典型降雨过程,确定不同降雨过程中不同时间分辨率下降雨侵蚀力的差异程度,并以此对每一场降雨的降雨侵蚀力进行修正,进而校正指定时间段的降雨侵蚀力。为验证该方法的有效性,以蓟运河上游地区为研究区,在Matlab 2010b中对当地典型降雨过程进行模拟,计算当地不同时间分辨率下降雨侵蚀力差异程度,并利用典型降雨年份2008年的TRMM 3B42数据（0.25°×0.25°空间分辨率及3 h时间分辨率）通过ENVI-IDL语言程序进行校正计算。结果表明,经过校正后,研究区年降雨侵蚀力分布约为900~2 900 MJ·mm/（hm^2·h）。该结果与这一地区多年平均降雨侵蚀力的量级及分布一致,说明该校正方法是一种切实可行的、能有效提高TRMM数据应用精度的方法;但是受TRMM数据空间分辨率的限制,该方法只适用于研究大中尺度区域降雨侵蚀力。The low temporal resolution of TRMM data could cause systematic errors in the rainfall erosivity calculation within the specified time period. For this reason,we propose a method of calibration in order to reduce the errors in this paper. Firstly, a relationship table of rainfall erosivity at different events and duration with typical rainfall process is established with historical rainfall data or numerical simulation; then, the corresponding difference is calculated from the above table based on the precipitation and duration of each rainfall in the study area; afterwards, the adjusted value of rainfall erosivity in each rainfall is calculated by multiplying the figure found in the pervious step by the original value of rainfall erosivity correspondingly ; finally, the calibrated value of daily, monthly or yearly rainfall erosivity is obtained by adding daily, monthly or yearly adjusted value of rainfall erosivity correspondingly. To verify the effectiveness of this calibration method, the typical rainfall process in the study area, the upriver regions of Jiyun River, was simulated within Matlab 2010b to obtain the relationship table, and then the rainfall erosivity in the study area was calculated using TRMM 3B42 data in 2008 with the spatial resolution of 0.25°×0.25° and the time resolution of 3 h. The calculation was conducted in the ENVI- IDL Language program and calibrated by the relationship table. The results showed that： the rainfall erosivity in the upriver of Jiyun River ranged from 900 to 2 900 MJ· mm/（hm^2· h） with the highest values in central area, followed by southern and northern parts, which was consistent with the local average annual values and distribution of rainfall erosivity. The results confirm that this method can effectively improve the precision of TRMM data＇ s application. Due to the limitation of spatial resolution of TRMM data, this calibration method is only applied in the rainfall erosivity calculation at large and middle scales. In order to improve the precision of

关 键 词：降雨侵蚀力 TRMM 系统误差 校正方法 蓟运河流域 

分 类 号：S157.1[农业科学—土壤学]