Spatial-temporal Evolution and Influencing Factors of Drought in Different Karst Areas based on TVDI
Drought has an important impact on agricultural production and construction of ecological environ-ments in karst areas.Study of drought in karst regions is of great significance for scientific drought prevention and drought relief,rock desertification management and ecological construction.The study area in this research comprises Du'an,Qiaojia,and Yinjiang,which are characterized by typical karst topography.The Temperature Vegetation Drought Index(TVDI)is calculated for these areas.Spatiotemporal pattern of drought and correla-tion between TVDI and meteorological and topographical factors are analyzed and discussed.The results show that the study areas mainly suffered mild drought,while moderate drought were mainly distributed in zones with karst development.The drought conditions in the three areas have been improving slightly in the last 20 years,and dry stress mainly concentrated in 2001～2010.It is found that the correlation between TVDI and the aver-age annual temperature and annual precipitation are weak or moderate,which are significantly lower than that in non-Karst areas.Negative correlations are found between TVDI in the three areas and DEM with R2 of 0.52,0.58 and 0.67 respectively.The correlation analysis of TVDI with topographic features and DEM shows that ar-eas with strong Karst development and widely distributed of rock fissures are more prone to drought than non-Karst areas,indicating that Karst development brings more drought stress.Furthermore,severity of the impact of Karst structure on occurrence of drought is Karst trough valley>Karst gorge>peak cluster depression.It is recommended that the impacts of the unique dualistic structure of Karst topography should be fully considered when analysing drought in Karst areas.
drought monitoringKarstTVDITopography and geomorphology
NETL
NSTL
万方数据
