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Shenyang Agricultural University (2020)

Research on Spatiotemporal Evolution Law of Meteorological Drought in Jilin Province

张瑞;

Titre : Research on Spatiotemporal Evolution Law of Meteorological Drought in Jilin Province

Auteur : 张瑞;

Grade : Doctoral Dissertation 2020

Université : Shenyang Agricultural University

Résumé partiel
Nowadays,in the context of global warming,coupled with the increase of global population and rapid economic development,the impact of drought is not only limited to the regional water crisis,but also began to seriously affect agricultural production and socioeconomic development.Drought,as one of the most important meteorological disasters in Jilin Province,has a great impact on the economy of Jilin Province,especially in crop production.Drought usually causes a lot of problems,such as serious shortage of local water resources,grassland degradation,land desertification and large area reduction of crops and so on in Jilin Province.In view of this,the temporal and spatial evolution of drought in Jilin Province was analyzed to clearly understand the reasonable assessment of its trend and provide the theoretical basis of flood-drought disaster monitoring and management in Jilin Province.It also provided a theoretical basis for drought prevention,disaster reduction and relief in Jilin Province,as well as the basic decision-making establishment of disasters.Based on the daily meteorological data average temperature(Tmm),diurnal temperature ranges(Tdelta),relative humidity(RH),solar radiation(Rs),wind speed(U2),geothermal flux(G),and precipitation(P)of 28 meteorological stations from 1958 to 2017 in Jilin Province,the spatial variation characteristics were analyzed.Then,Z,SPI,SPEI.T and SPEI.PM drought indexes were selected for comparative analysis,in order to determine the suitable drought index in Jilin Province,and to analyze the frequency,range,intensity,length,starting and ending time of drought,as well as the spatial distribution,trend and evolution characteristics of drought in different time scales(year,season and month).After that,the Morlet wavelet function was selected to study the periodic variation of drought in Jilin Province.In addition,the drought duration and drought accumulation intensity were used to establish a two-dimensional copula joint distribution to analyze the characteristics of drought recurrence period.Finally,using the global sensitivity analysis EFAST method,the sensitivity analysis of the relevant meteorological parameters of SPEI.PM index was carried out to explore the response degree,spatial distribution and sensitivity ranking of these meteorological factors to SPEI.PM.Among them,the main results of the above studies were as follows :(1)Study on the suitability of drought Index(1)The Z and SPI indexes were used to compare the drought conditions respectively on the annual,monthly and seasonal scales in Jilin Province.The SPI index was more suitable than Z index for drought monitoring and evaluation when there was only precipitation data in Jilin Province.From the point of space and time,by comparing the four indexes of Z,SPI,SPEI.T and SPEI.PM,the actual drought situation was verified by drought disaster area,non-harvest area and “Disaster Code” of Jilin Province,which suggested that SPEI.PM index was the most suitable drought index for drought assessment in Jilin Province.(2)In Jilin Province,the trend of drought in different of yearly,seasonal and monthly scales was different,and the droughts in spring and winter showed the upward trend,while most of the droughts in summer and autumn showed the downward trend.From the spatial frequency of drought,it was concluded that spring drought was mainly distributed in the south-central,southeast and northeast of Jilin Province.Summer drought was mainly distributed in the western,central and southeastern parts of Jilin Province.Autumn drought was mainly distributed in the western,central and eastern regions of Jilin Province.Winter drought was mainly distributed in the western and southcentral regions of Jilin Province.From the point of view of time,the sequence of drought frequency in different grades of yearly,seasonal and monthly scales mainly reflected the following characteristics : light drought > medium drought > severe drought > special drought ;the frequency on annual scale that was close to that of monthly scale,seasonal scale,the frequency of light drought was winter drought > autumn drought > spring drought > summer drought ;the frequency of medium drought was summer drought > autumn drought > winter drought > spring drought ;the frequency of severe drought was winter drought > spring drought > summer and autumn drought ;the frequency of special drought was spring drought > summer drought > autumn drought > winter drought.(3)Based on the study of drought stations proportion,it was concluded that there were significant differences in drought stations proportion in different years and seasons.On the whole,provincial drought = local drought = inconspicuous drought > regional drought

Mots clés : Evolution law of drought; Periodic analysis; Copula; Sensitivity analysis;

Présentation (CNKI)

Page publiée le 22 octobre 2020, mise à jour le 26 octobre 2021