Drought has become the main natural disasters affecting winter wheat production in Henan provinceand it is very important to monitor drought conditions. The leaf area index (LAI) and land surface temperature(Ts) data from MODIS/Terra between February 26 and June 1 in 2000, 2005, 2010 and 2015 were used toevaluate applicability of Temperature LAI Dryness Index (TLDI) based on LAI-Ts space for drought monitoringwhen NDVI was not saturated. Comparing with soil moisture in 10cm depth from the meteorological stations inHenan province, there was a highly significant correlation between TLDI and 10cm-depth soil moisture(P<0.05),and their correlation coefficient varied between 0.5212 and 0.7467, which indicated that TLDI, coming fromLAI-Ts space, could effectively detect the agriculture drought when NDVI was not saturated. In addition, LAI-Tsspace is triangular in the early stage of vegetation and it gradually evolved into a trapezoid with the increase ofvegetation coverage. The drought events of Henan Province from February 26 to June 1 in 2000, 2005, 2010 and2015 were assessed by TLDI. Drought in Henan Province was mainly occurred in the central and western regions,the southwest and the northern region. The drought occurred frequently at the beginning of the March which wasthe turning green stage of winter wheat and May which was the stage from flowering to filling of winter wheat,every year.%以河南省返青-成熟期冬小麦为研究对象,利用研究区2000、2005、2010及2015年每年2月26日-6月1日MODIS产品叶面积植被指数(LAI)和地表温度(Ts)数据,探讨当NDVI未达到饱和时,基于LAI-Ts特征空间的温度叶面积干旱指数(TLDI)能否用于旱情监测,并利用气象站实测10cm土壤湿度数据进行精度验证,进而应用该指数对河南省冬小麦旱情进行监测.结果表明:TLDI与实测土壤湿度之间存在显著负相关关系(P<0.05),相关系数大小在0.5212~0.7467.当NDVI未达到饱和时,基于LAI-Ts特征空间的TLDI可作为干旱监测指标,补充拓展基于植被指数和地表温度的旱情监测方法.在冬小麦返青期即植被覆盖度较低时 LAI-Ts特征空间呈三角形,随着植被覆盖度的提高逐渐演变为梯形.河南省旱情主要分布在中西部、西南部以及北部地区,每年3月上旬及5月为旱情频发期,分别处于冬小麦返青期和开花-灌浆期.
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