【摘要】 地表昼夜温差(ΔT)与植被覆盖度和土壤含水量等密切相关。文中在条件植被温度指数(VTCI)干旱监测方法的相关研究成果的基础上,应用MODIS数据,通过引入ΔT探究条件植被温差指数(ΔT-VTCI)干旱监测方法的可行性。ΔT-VTCI既考虑了区域内NDVI的变化,又考虑了在NDVI相同的条件下ΔT的变化。陕西省关中平原2000-2011年每年4月上、中、下旬和5月上旬的干旱监测结果表明,ΔT-VTCI的干旱监测结果与VTCI的干旱监测结果基本相符,可用于研究干旱的时空变化特征。通过对比分析多年多旬VTCI和ΔT-VTCI的干旱监测结果,发现两种方法得到的干旱监测结果的散点主要分布在1:1对角线附近,且呈显著的线性相关关系,说明这两种方法得到的干旱监测结果具有可比性。更多还原

【Abstract】 Diurnal difference of land surface temperature( ΔT) is closely related to changes of vegetation coverage and soil moisture. On basis of VTCI( vegetation temperature condition index) the drought monitoring approach was developed,and considering the ΔT,the vegetation temperaturedifference condition index( ΔTVTCI) was developed for monitoring droughts by using MODIS data. The VTCI and ΔTVTCI drought monitoring results in the Guanzhong Plain from early April to later May in 20002011 were studied. The ΔTVTCI drought monitoring approach not only relates to the NDVI changes in a region,but also gives emphasis on the changes of ΔT of pixels which have a given NDVI value. After comparing and analyzing the VTCI and ΔTVTCI drought monitoring results in the same ten days,it is obvious that the distributions of droughts which were calculated by the two approaches are similar. Moreover,both of them were in accordance with the actual drought distribution. There are significant linear correlations between the VTCI and ΔTVTCI,which indicates the two monitoring results are comparable at the same time scale.更多还原