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Northwest A&F University (2020)

Study on the Temporal and Spatial Changes of Different Types of Drought and Their Relationship

赵会超;

Titre : Study on the Temporal and Spatial Changes of Different Types of Drought and Their Relationship

Auteur : 赵会超;

Grade : Master’s Theses 2020

Université : Northwest A&F University

Résumé partiel
Drought is a universal climate phenomenon,and it is also a kind of natural disaster that will cause great loss and influence to human society.Drought can lead not only to widespread food loss,water shortages and environmental degradation,but also to famine,economic dislocation,war,social unrest and even a change of government.In addition,the occurrence of drought will also cause the deterioration of social natural resources,and then lead to a series of socio-economic environmental and ecological problems.Therefore,drought is not only related to the ecological environment,but also to the social economy,and is closely related to the development of human beings.Drought has become a key issue of concern to all countries.Based on the global land assimilation data and remote sensing data,this paper analyzes the temporal and spatial changes of water cycle related factors,remote sensing monitoring of drought and the characteristics of different types of drought in China.Firstly,the spatial-temporal evolution characteristics of water cycle elements,which are directly related to drought,are analyzed by using Mann Kendall trend test and wavelet analysis.Secondly,the temporal and spatial characteristics of soil moisture,temperature,surface temperature and vegetation index of each layer are analyzed.Two kinds of Temperature Vegetation Drought Index(TVDI)are calculated by fitting the dry and wet edge equations,and the applicability of the two kinds of TVDI in soil moisture monitoring of different regions and depths is analyzed.The distribution characteristics of various probability density functions of precipitation,soil moisture and groundwater runoff are analyzed,the optimal probability density function is selected,and the parameters are estimated.On this basis,the standardized precipitation index(SPI),the standardized soil moisture index(SSI)and the standardized runoff index(SRI)are calculated,and the spatial and temporal characteristics of SPI,SSI and Sri and the relationship between drought development is analyzed by Pearson correlation analysis and run theory.Finally,based on SPI,SSI and Sri,the corresponding drought variables,i.e.drought frequency,drought duration and drought magnitude,which are obtained by using the run theory,and the change rules of each drought variable are compared

Mots clés : Soil drought monitoring; Frequency analysis; Run theory; Drought variable; Land surface parameter; Spatiotemporal Variations;

Présentation (CNKI)

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