北疆地区不同草地类型MODIS植被指数变化动态及其与气候因子的关系

利用新一代卫星遥感数据TERRA/MODIS,结合地面20个气象台站提供的数据,以北疆地区为研究区域,分析了温性草原、低地草甸、山地草甸、温性草甸草原、温性荒漠草原和温性荒漠6种代表性草地植被指数的时空变化特征.以2004,2005年4～10月的月度变化为例,研究了不同草地类型在各个生长阶段植被指数的变化和草地的生长状况.研究结果表明,EVI对植被变化的敏感性要强于NDVI的,但是在植被生长状况较好的草地,NDVI比EVI更稳定.植被盖度比较好的草地类型(如温性草甸草原、山地草甸)的植被指数与温度和降水都表现出很强的相关性,但植被稀疏的草地(如温性荒漠、温性荒漠草原)的植被指数与温度的相关性比较弱,与降水的关系更弱.

Dynamics of MODIS vegetation indices and their relationships with meteorological factors for different grassland types in northern Xinjiang

Taking Northern Xinjiang as an example, the new generation of satellite remote sensing data of moderate resolution imaging spectroradiometer (MODIS) were used by combining with the 20 climate monitoring station data. The temporal and spatial changes of the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) of six typical grasslands of temperate steppe, low-land meadow, temperate meadow steppe, temperate desert steppe and temperate desert were analyzed. According to monthly change from April to October in 2004 and 2005, vegetation index changes of various grassland classes during growing seasons were studied in detail. The results indicated that EVI is more sensitive to the change of vegetation than NDVI, but for the vegetation in good status, the stabilization of NDVI is better than EVI. For the grassland classes with better coverage, such as temperate meadow steppe and mountain meadow, the relationship between vegetation indices and temperature and precipitation is strong, but for the grassland classes with low coverage, such as temperate desert and temperate desert steppe, the correlation between vegetation indices and temperature is weak, and the relationship between vegetation indices and precipitation is even weaker.