| The Panxi region is an ecological barrier on the upper reaches of the Yangtze River in China and has a very significant impact on the ecological environment construction and economic development of the entire basin.With climate deterioration the area of damaged and lost crops in the Panxi region has been increasing according to statistics.In this situation,this paper used ‘3S' technology,which has already been used in disaster science and ecology,to study drought vulnerability in Panxi region.According to the collection,storage,management,calculation,display and analysis of the drought vulnerability data,which can provide theoretical basis and data support for the establishment of the drought vulnerability assessment model in the study area.Based on the previous research results,this paper selected multi-temporal outboard satellite remote sensing data and meteorological data,and comprehensively used spatial information technology to carry out remote sensing surveys and monitoring of the arid environment in the Panxi region.In the combination of relevant natural geographical resources in study area,this paper used AHP-Entropy combination model to evaluate drought vulnerability from 2008 to 2012,and analysed the characteristics of its spatial and temporal changes.The main research contents of this paper are as follows:(1)Analysis of the spatial and temporal characteristics of drought based on meteorological data and remote sensing data.Based on the monthly precipitation data from Panzhihua Meteorological Station during 2008-2012,the characteristics and trends of precipitation changes at each site were analyzed;the advantages of the Standardized Precipitation Index(SPI)in drought analysis were used to classify the SPI into 5 levels according to the national standards for meteorological drought,and this paper analysed drought conditions in the study area and its sub-stations;Based on the NDVI and LST remote sensing data standardized of the Panxi region during 2008-2012,this paper used the IDL language to program and output monthly NDVI-LST feature space scatter plot figure to determine the parameters of the dry.So that monthly Temperature Vegetation Drought Index(TVDI)can be gotten and soil moisture data are used to get spatial characteristics of drought distribution in the Panxi region.(2)Construct drought vulnerability assessment model of the Panxi region.Based on natural potential vulnerability and human interference vulnerability,this paper selected TVDI,SPI,soil erodibility(K value),DEM,river network density,effective irrigation area,vegetation coverage,total urban water supply,and land use to construct drought vulnerability assessment model of the Panxi region.The subjective and objective weights of the indicators were obtained by using the AHP-Entropy method combination model,and the comprehensive weights of the indicators were determined by the game theory method.The drought vulnerability assessment results in the study area were calculated.Assessment results were divided into 5 levels: slight,light,moderate and heavy to get temporal and spatial distribution of drought vulnerability in the Panxi region.(3)Temporal and spatial changes of drought vulnerability and its impact analysis in the Panxi region.Through the spatial analysis of the static vulnerability assessment results of drought vulnerability in different years,the relative changes of drought vulnerability based on pixels are obtained.The spatial correlation analysis between the evaluation results and each indicator has been made to obtain the main factors affecting the drought vulnerability in the study area;the correlation analysis between the evaluation results and other socio-economic factors has been carried out to get the relationship between these factors.Based on the above results,the drought vulnerability of study area was zoned and related governance proposals were put forward in a targeted manner.It provided a theoretical basis for understanding the arid environment of study area and preventing of drought. |
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