Application Of TRMM Precipitation In VIC Hydrological Model For Streamflow Simulations In The Upstream Of Yangtze River Basin

Precipitation is an important part of the surface water cycle,it is important for hydrological research and water resources management and decision making.The quality of precipitation data has a great influence on the model hydrological process simulation.Many of the watersheds in the central and western regions of China are constrained by geographical and economic factors,and the distribution of weather stations is sparse.The acquisition of high precision precipitation data is difficult,which also restricts the work of hydrological simulation.The TRMM(Tropical Rainfall Measuring Mission)precipitation observation satellite,launched in 1997,has been improved by several algorithms and has high estimation accuracy for precipitation.It is widely used in many parts of the world and provides a good source of precipitation data for hydrological simulation.The Yangtze River is the largest river in China,it has a very important impact on agriculture,industry and social development of our country.More than 40% of the total area of the Yangtze River Basin is occupied by the Cuntan watershed.It is of great practical significance to carry out hydrological and ecological research in this basin.Based on the daily data of 0.25 ° lattice and the runoff data of Cuntan station in 1981-2010,and the TRMM 3B42 precipitation data from 2003 to 2010.Using the combination of satellite precipitation data and VIC(Variable Infiltration Capacity)hydrological model to assess the capacity of different versions of TRMM precipitation products in the study of regional water balance studies.Conclusions as below:(1)TRMM V6 and V7 in the study of the basin over the years of daily precipitation in the spatial distribution and time-varying estimates is consistent with the ground measured data basically.The evaluation of indicators have a very good result.TRMM RTV6 and RTV7 can not accurately grasp the spatial variation trend of precipitation in the whole study basin,and the estimated daily precipitation is diffierent from the measured value.However,the accuracy of RTV6 and RTV7 in the Jialing River Basin is much better than that in other research areas.(2)Estimates of precipitation within the study basin,V7 on the whole of the best indicators of the error,compared with V6 has a comprehensive upgrade.Although the RTV6 and RTV7 precipitation estimates have a big deviation with the measured values,RTV7 is still on the basis of RTV6,on the monthly scale precipitation estimates have improved significantly.(3)VIC large-scale distributed hydrological model has higher accuracy of runoff simulation above the Cuntan basin of Yangtze River,compared with the measured data of the Cuntan station,the deviation is small.Nash efficiency coefficient can reach 0.8 or more.It can meet the need for long-term runoff simulation of the research basin.(4)V7 has the best runoff simulation capability in the study watershed and is very close to the runoff results which simulated by measured precipitation.Although the simulation results of RTV7 are very different from the measured runoff,it is still a good way to reflect the trend of the runoff of the Cuntan station.Combined with precipitation data and runoff data of different versions of TRMM precipitation products.TRMM V6 and V7 are highly applicable in the study watershed.TRMM RTV7 has a good performance after the parameters of the re-rate in the runoff simulation.Overall V7 version of the TRMM precipitation products has all aspects of the upgrade in the precipitation accuracy and hydrological simulation than the V6 version.It has great potential to conducive water resources management.