基于TVDI的长江南源干旱时空动态变化监测

随着全球变暖,干旱成为全球危害最为严重的自然灾害之一,对农业等事关人类福祉的领域产生巨大影响。该文以重要农牧区——长江南源为研究区,基于地表温度数据和归一化植被指数数据计算出2000年以来长江南源温度植被干旱指数,并以该指数对长江南源植被生长季的干旱状况进行时空动态监测分析。结果表明,2000年以来,干旱和偏旱的区域在长江南源的北部、中部和东北部,占源区面积的33.33%;湿润和偏湿的区域在研究区域的南部、西南部,占源区面积的37.02%。长江南源56.41%的区域趋向干旱,41.96%的区域趋向湿润。湿润区域在2000—2004年间呈收缩态势,占长江南源的面积比重由42.54%下降到35.25%;2004—2011年,呈扩张态势,所占面积比重上升到38.84%,2011年后呈收缩态势,所占面积比重下降到36.79%。总体来看,TVDI有较强可靠性,可用于长江南源乃至三江源区干旱监测预警工作。

With global warming,drought has become one of the most serious natural disasters in the world,which has a great impact on agriculture and other areas related to human well-being.This studycal culated the Temperature Vegetation Dryness Index(TVDI)of the southern source region of the Yangtze River since 2000 based on the Land Surface Temperature(LST)products and Normalized Difference Vegetation Index(NDVI)products,and used the TVDI to monitor and analyze the spatio-temporal dynamic of drought of the growing season in the southern source region of the Yangtze River.The results show that,since 2000,the arid and arid areas have been centralized in the north,middle and northeast of the southern source of the Yangtze River,accounting for 33.33%of the source area;the humid and humid areas are in the south and southwest of the study area,accounting for 37.02%of the source area.56.41%of the areas in the southern source of the Yangtze River tend to be dry,and 41.96%of the areas tend to be humid.The humid area showed a shrinking trend from 2000 to 2004,and the proportion of the area in the southern source of the Yangtze River decreased from 42.54%to 35.25%.The proportion of the humid area increased to 38.84%during 2004—2011,and the proportion of the humid area decreased to 36.79%after 2011.As a whole,TVDI can be used for drought monitoring and early warning in the southern source region of the Yangtze River and even the Three River Source Region due to its reliability.