Assessing the adequacy of bias corrected IMERG satellite precipitation estimates using extended mixture distribution mapping method over Yangtze River basin
Satellite precipitation estimates(SPE)product with high spatiotemporal resolution is a potential alternative to traditional ground-based gauge precipitation.However,SPE is frequently biased due to its indirect measurement,and thus bias correction is necessary before applying to a specific region.An improved distribution mapping method,i.e.,Extended Mixture Distribution(EMD)of censored Gamma and generalized Pareto distributions,was established.The advantage of EMD method is that it describes both moderate and extreme values well and carries on the traditional censored,shifted Gamma distribution to combine the precipitation occurrence/non-occurrence events together.Then the EMD method was applied to the Integrated Multi-satellitE Retrievals for GPM product(IMERG)as statistical post-processing over Yangtze River basin.The Version-2 Gridded dataset of daily Surface Precipitation from China Meteorological Administration(GSP-CMA)was taken as reference.The adequacy of bias corrected IMERG precipitation was assessed and the results showed that(1)the Root Mean Squared Error and Relative Bias between bias-corrected IMERG precipitation and reference are significantly reduced relative to the raw IMERG estimates;(2)the performance of extreme values of IMERG in Yangtze River basin is enhanced since both the under-and over-estimation of the raw IMERG are compromised,due to the generalized Pareto distribution introduced in EMD which is enable to describe the extreme value distribution.This highlights the improved distribution mapping method,EMD is flexible and robust to bias correct the IMERG precipitation to obtain higher accuracy of SPE despite the coarse resolution of reference.
Qiumei Ma Lihua Xiong Chong-Yu Xu Shenglian Guo
State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 43 State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 43
国际会议
2018 International Symposium on Water System Operations(ISWRSO 2018)(2018年水资源系统及调度国际研讨会)
北京
英文
1-5
2018-10-12（万方平台首次上网日期，不代表论文的发表时间）