In the context of global warming,precipitation forms are likely to transform from snowfall to rainfall with a more pronounced trend.The change in precipitation forms will inevitably affect the processes of regional runoff generation and confluence as well as the annual distribution of runoff.Most researchers used precipitation data from the CMIP5 model directly to study future precipitation trends without distinguishing between snowfall and rainfall.CMIP5 models have been proven to have better performance in simulating temperature but poorer performance in simulating precipitation.To overcome the above limitations,this paper used a Back Propagation Neural Network(BNN)to predict the rainfall-to-precipitation ratio(RPR)in months experiencing freezing-thawing transitions(FTTs).We utilized the meteorological(air pressure,air temperature,evaporation,relative humidity,wind speed,sunshine hours,surface temperature),topographic(altitude,slope,aspect)and geographic(longitude,latitude)data from 28 meteorological stations in the Chinese Tianshan Mountains region(CTMR)from 1961 to 2018 to calculate the RPR and constructed an index system of impact factors.Based on the BNN,decision-making trial and evaluation laboratory method(BP-DEMATEL),the key factors driving the transformation of the RPR in the CTMR were identified.We found that temperature was the only key factor affecting the transformation of the RPR in the BP-DEMATEL model.Considering the relationship between temperature and the RPR,the future temperature under different representative concentration pathways(RCPs)(RCP2.6/RCP4.5/RCP8.5)provided by 21 CMIP5 models and the meteorological factors from meteorological stations were input into the BNN model to acquire the future RPR from 2011 to 2100.The results showed that under the three scenarios,the RPR in the number of months experiencing FTTs during 2011-2100 will be higher than that in the historical period(1981-2010)in the CTMR.Furthermore,in terms of spatial variation,the RPR values on the south slope will be larger than those on the north slope under the three emission scenarios.Moreover,the RPR values exhibited different variation characteristics under different emission scenarios.Under the low-emission scenario(RCP2.6),as time passed,the RPR values changed slightly at more stations.Under the medium-emission scenario(RCP4.5),the RPR increased in the whole CTMR and stabilized on the north slope by the end of this century.Under the high-emission scenario(RCP8.5),the RPR values increased significantly through the 21st century in the whole CTMR.This study may help to provide a scientific management basis for agricultural production and hydrology.

REN Rui;LI Xue-mei;LI Zhen;LI Lan-hai;HUANG Yi-yu

Faculty of Geomatics,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of Regional Climate-Environment in Temperate East Asia,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;National-Local Joint Engineering Research Center of Technologies and Applications for National Geographic State Monitoring,Lanzhou 730070,China;Gansu Provincial Engineering Laboratory for National Geographic State Monitoring,Lanzhou 730070,China;Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi 830011,China

山地科学学报（英文版）

[1]REN Rui;LI Xue-mei;LI Zhen;LI Lan-hai;HUANG Yi-yu-.Projected change in precipitation forms in the Chinese Tianshan Mountains based on the Back Propagation Neural Network Model)[J].山地科学学报（英文版）,2022(03):689-703

BNN,FTTs,CTMR

Projected,precipitation,forms,Chinese,Tianshan,Mountains,Back,Propagation,Neural,Network,Model,In,context,global,warming,are,likely,from,snowfall,rainfall,pronounced,will,inevitably,processes,regional,runoff,generation,confluence,well,annual,distribution,Most,researchers,used,data,CMIP5,directly,study,future,trends,without,distinguishing,between,models,have,been,proven,better,performance,simulating,temperature,poorer,To,overcome,above,limitations,this,paper,predict,RPR,months,experiencing,freezing,thawing,transitions,We,utilized,meteorological,air,pressure,evaporation,relative,humidity,wind,speed,sunshine,hours,surface,topographic,altitude,slope,aspect,geographic,longitude,latitude,stations,calculate,constructed,system,impact,factors,Based,decision,making,trial,evaluation,laboratory,method,DEMATEL,key,driving,transformation,were,identified,found,that,was,only,affecting,Considering,relationship,under,different,representative,concentration,pathways,RCPs,RCP2,RCP4,RCP8,provided,by,input,into,acquire,results,showed,three,scenarios,number,during,higher,than,historical,period,Furthermore,terms,spatial,variation,values,south,larger,those,north,emission,Moreover,exhibited,characteristics,Under,low,passed,changed,slightly,medium,increased,whole,stabilized,century,significantly,through,21st,This,may,help,scientific,management,basis,agricultural,production,hydrology

0.465778