基于TVDI的内蒙古植被生长期干旱研究

利用内蒙古地区2007、2008年植被生长期（4～9月）的MOD13A3和MOD11A2数据,建立温度植被干旱指数（TVDI）模型,并对其进行验证,将得到的内蒙古地区的TVDI数据划分等级,分析了其时空变化特征。结果表明,①从气象站点、样点的土壤含水量与TVDI的散点图看出,TVDI作为内蒙古植被生长期的旱情评价指标具有一定的合理性。②内蒙古地区植被生长期主要以轻旱和中旱为主,占全区面积的70%以上;湿润、正常和重旱的面积所占比例较小。③在时间尺度上,内蒙古地区4、5、6月旱情比较严重,7、8月份旱情有所缓解,是全年干旱最轻的时段,而进入9月份旱情又逐渐加剧;在空间尺度上,东北部地区4～9月份旱情比较轻,干旱等级主要以湿润和正常为主;其他地区在7、8月份旱情比较缓和,以轻旱和中旱为主;其中西部的沙漠地区在4～9月份的旱情均十分严重。

Research on the Drought during the Vegetation Growth Period of Inner Mongolia Based on TVDI

Based on the MOD11A2 and MOD13A3 data about the vegetation growth peirod(April to September) in 2007 and 2008,the TVDI model was constructed and verified,after which the classification grades of TVDI data in Inner Mongolia were obtained,and its spatial and temporal variation features were analyzed.The results indicated that,①as shown by the meterological stations,soil moisture content of the samples and TVDI scattergraph,TVDI was reasonable to act as the evaluation index of drought during the vegetation growth period in Inner Mongolia.②During the vegetation growth period,most areas in Inner Mongolia were affected by slight and moderate drought,occupying over 70% of the whole area;while the moist,arid-moist balanced area accounted for a very small proportion.③The drought in Inner Mongolia was very severe on April,May and June,less severe on July and August,and gradually intensitied on September;in the northeast Inner Mongolia area,the drought was very slight on April and September at the moist and normal levels;the drought was moderate and slight on July and August in other areas;while the drought in the western desert areas was very serious from April to September.