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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。
The surface temperature difference between day and night (ΔT) is closely related to vegetation coverage and soil water content. Based on the related research results of drought monitoring methods of conditional vegetation temperature index (VTCI), MODIS data was used to investigate the feasibility of drought monitoring method using conditional temperature difference index (ΔT-VTCI) by introducing ΔT. ΔT-VTCI not only considers the change of NDVI in the region, but also takes into account the change of ΔT under the same condition of NDVI. The results of drought monitoring in the middle, late, late May and early May in the Guanzhong plain of Shaanxi Province during 2000-2011 from April to April each year show that the results of drought monitoring of ΔT-VTCI are basically consistent with the results of drought monitoring of VTCI and can be used to study the spatio-temporal variations of drought . By comparing and analyzing the drought monitoring results of VTCI and ΔT-VTCI for many years, we found that the scatter points of the drought monitoring results obtained by the two methods are mainly distributed around the 1: 1 diagonal with a significant linear correlation, indicating that these two The drought monitoring results obtained by the method are comparable.