Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Chine → 2021 → Study on the Propagation Characteristics and Laws of Drought in Meteorology-Agriculture-Disaster Loss

Xi’an University of Technology (2021)

Study on the Propagation Characteristics and Laws of Drought in Meteorology-Agriculture-Disaster Loss

代萌

Titre : Study on the Propagation Characteristics and Laws of Drought in Meteorology-Agriculture-Disaster Loss

Auteur : 代萌

Grade : Master These 2021

Université : Xi’an University of Technology

Résumé partiel
In the background of global climate warming,the water cycle is intensified,and drought events are more and more frequent,which has a great impact on people’s life.At present,agricultural drought,as a major factor directly threatening food security,has attracted much attention.However,the evolution process and propagation law of drought have not been fully revealed,which makes drought resistance work lack of theoretical support.Therefore,it is of great significance to explore the propagation law of meteorological drought to agricultural drought in the changing environment.The main stream of Wei River and its two tributaries(Jing River and Beiluo River)are taken as the research object in this paper.The Standardized Precipitation Index(SPI)and Standardization Soil Moisture Index(SSMI)are used to characterize meteorological drought and agricultural drought respectively,and the characteristics of spatiotemporal evolution of drought are analyzed.Based on the Bayesian theory framework,the Copula function is used to quantify the seasonal propagation time and trigger threshold of meteorological drought to agricultural drought,and the trigger thresholds of different levels of drought losses under agricultural drought stress are calculated.In addition,the dynamic evolution law and influencing factors of propagation time are explored.The main research results of this paper are as follows :(1)It is revealed that the temporal and spatial variation characteristics of meteorological drought and agricultural drought by using Mann-Kendall non-parametric rank correlation test and Morlet wavelet analysis,heuristic segmentation algorithm and run theory.In terms of time,it is shown that the SPI and SSMI sequences of the three sub-regions have significant downward trends on the whole.The SPI sequences of the three regions have the main period of 18,10 and 17 years in the 51-year evolution process respectively,and SSMI series have 18,6 and 18 years.The SPI sequence of Beiluo River has a variation point in 1965,and the SSMI sequences of three subregions have variation point in 1990,1969 and 1985,respectively.In space,the average duration and severity of agricultural drought are significantly greater than that of meteorological drought,and the agricultural drought in the main stream is the most serious.(2)Based on the framework of Bayesian theory,it is calculated that the propagation time from meteorological to agricultural drought.The results show that the static propagation time of meteorological drought to agricultural drought in spring is the longest,which is 7.3,8.0 and 7.3 months,respectively.The propagation time in autumn of Jing River is the shortest,which is 2.7 months.In addition,the spring and autumn propagation time of meteorological drought to agricultural drought in the main stream is longer than that in summer and winter,and the spring and winter propagation times of drought in Jing River and Beiluo River are longer than that in summer and autumn.Based on the moving window of 25 years,it is found that the propagation times from meteorological drought to different grades agricultural drought of the four seasons of main stream,the summer and winter of Jing River and the spring of the Beiluo River are significantly shortened,and the autumn propagation time of the Beiluo River is significantly longer.

Mots clés : Wei River Basin ;Bayesian theory framework ;Copulas functions ;propagation time ;trigger threshold ;loss-causing threshold ;

Présentation (CNKI)

Page publiée le 26 octobre 2021