植被-地温指数(NDVI-LST)在新疆干旱监测中的适用性

采用MODIS归一化植被指数(Normalized Difference Vegetation Index,NDVI)和地表温度(Land Surface Temperature,LST)产品数据分析新疆2000—2015年生长季3阶段NDVI与LST的时空变化特征及相关关系;利用多元线性回归方法分析不同时期影响NDVI-LST相关关系的气象因子;并按不同土地覆盖与土地利用(Land-Use and Land-Cover Change,LUCC)类型分析NDVILST相关关系时空变化特征。结果表明:(1)生长季3时期LST与NDVI均存在显著相关关系,可利用两者的特殊关系进行干旱评估。(2)不同时期气象因子对NDVI-LST相关关系影响程度不一;并且不同LUCC类型的NDVI-LST相关关系也存在明显差异。(3)在生长季中期利用植被健康指数(Vegetation Health Index,VHI)对新疆大部分地区的植被健康和干旱进行监测是可行有效的,而初期与末期的干旱评估需要利用其他干旱指数进行补充研究。

Adaptability of drought situation monitor in Xinjiang with the NDVI-LST index

In this study, the spatial-temporal characteristics of vegetation status, drought conditions, and their correlation were studied through three phases of the normalized difference vegetation index (NDVI), land surface temperature(LST)-moderate resolution imaging spectroradiometer (MODIS) database during the growing season in Xinjiang from 2000 to 2015. In addition, a multivariate linear regression method was used in this study to analyze the meteorological factors that could influence the relationship between NDVI and LST of different phases. The spatial-temporal characteristics of the relationship between NDVI and LST were analyzed by dividing different land use cover changes (LUCC). The results showed that (1) there was a significant correlation between LST and NDVI in the third quarter of the growth season, and drought conditions could be evaluated using the relationship between NDVI and LST. (2) The influence of meteorological factors on the NDVI-LST correlation was different in various phases in Xinjiang. Moreover, there were significant differences in NDVI-LST correlations among different LUCC. (3) It was effective to monitor vegetation health and drought conditions in most areas of Xinjiang using a vegetation health index in the middle of the growing season, whereas earlier and latter drought assessments needed to be supplemented by other drought indices.