Research On The Applicability Of Multi-source Meteorological Precipitation Data In The Yunnan-Guizhou Platea

In recent years,with the continuous improvement of satellite technology,the research and application of multi-source meteorological precipitation data based on satellite observation has increasingly become a hot spot in the field of hydrometeorology.Multi-source meteorological precipitation data differs from station precipitation in that it functions as surface precipitation data,and is characterised by its wide coverage,the availability of data in real time,and increasing accuracy as satellite technology continues to improve.Therefore,it can effectively solve the problem of precipitation data sources in areas with insufficient observation stations or complex topography,large variations in the spatial distribution of precipitation,and stations that cannot be covered,and is of great value to local industrial,agricultural and ecological water use calculations as well as water resources evaluation and management.This paper takes the Yunnan-Kweichow-Plateau region as the study area,and on the basis of the previous screening of multi-source meteorological products,three precipitation products,TRMM 3B42,CMFD and CMADS,were selected and their applicability in the study area was carried out.Using the measured precipitation data from2008 to 2018 at 59 actual stations in the Yunnan-Kweichow-Plateau region,the precipitation products were evaluated for accuracy from multiple time scales,spatial scales,different precipitation intensities,and different topographic conditions using multiple evaluation indicators;meanwhile,two typical watersheds in the Yunnan-Kweichow-Plateau region,the Erhai watershed and the Yunlong reservoir watershed,were selected to carry out watershed rainfall runoff simulations using three product-driven distributed hydrological models and compared with the actual measured runoff for a comprehensive evaluation of the applicability of the three products.The main conclusions of the thesis are as follows:(1)All three multi-source precipitation products have good performance and can be applied to the calculation of local water resources,but CMFD performs best;the precipitation products perform slightly worse on the daily scale and better overall on the annual,seasonal and monthly scales;they have good results in most areas,but there are some more prominent overestimation and underestimation points;the three precipitation products have the highest hit rate and lowest false alarm rate for no rain and light rain,with the hit rate gradually decreasing as the intensity of precipitation increases;the precipitation products have larger absolute errors in rainy months,making the products somewhat limited in terms of storm flood calculation accuracy.(2)The three multi-source precipitation products are better at portraying precipitation under different terrain conditions with CMFD precipitation data,followed closely by TRMM3B42,and CMADS performing poorly.To some extent,increased elevation,slope and topographic relief can make the data less accurate,but in general,topography does not have a significant effect on the accuracy of the three precipitation data.(3)Three multi-source meteorological precipitation products were used to drive the SWAT model to carry out monthly-scale runoff simulations in the Erhai and Yunlong reservoir basins,and the simulation effects were evaluated using R~2,NSE,and PBIAS values.In this study,two rate scenarios were set based on the selection of sensitivity parameters,which were determined separately for each data(Scenario 1)and uniformly using sensitivity parameters determined from the measured data(Scenario 2).Under both schemes,during the rate period of the runoff model,the measured precipitation data performed best in both watersheds,while the best performance of the multi-source meteorological data was CMFD in the Erhai watershed and TRMM 3B42 in the Yunlong reservoir watershed;during the validation period of the runoff model,the measured precipitation performed best in both watersheds,while the best performance of the multi-source meteorological data was CMADS in the Erhai watershed and TRMM 3B42 in the Yunlong reservoir watershed.TRMM 3B42.(4)The results of the combined accuracy and runoff simulation evaluations show that all three precipitation products perform well,with the CMFD performing better in the accuracy evaluation and also in the runoff simulation.This indicates that the three precipitation products can,to a certain extent,replace or compensate for the shortcomings of the measured stations,especially in areas where data are not available,and be used in local hydrological studies and water resources analysis and calculations.