2000—2012年鄂尔多斯高原植被动态及干旱响应

Vegetation dynamics and its responses to drought in Ordos Plateau

针对鄂尔多斯高原植被覆盖变化受干旱胁迫的状况,该文结合降水和气温的协同变化,以2000—2012年生长季的MODIS-NDVI数据和同期降水、温度和帕尔默干旱指数为依据,采用线性趋势分析、标准偏差分析和相关性分析等方法,对鄂尔多斯高原植被与气候变化的相关关系和干旱异常变化对植被动态的影响进行了研究。结果表明:鄂尔多斯高原生长季及季节(春季、夏季和秋季)植被归一化植被指数主要受降水的控制和干旱的制约,秋季归一化植被指数更多地受到夏季干旱的影响。与气象因子的空间相关分析表明,春季温度上升有利于研究区北部归一化植被指数像元的增加。在荒漠草原和沙漠地区,夏季干旱与归一化植被指数的相关关系最强。秋季降水对典型草原归一化植被指数的提升显著。

According to the condition of vegetation changes stressed by drought in Odors Plateau,combining with the synergistic change of precipitation and temperature,this paper assessed and predicted the trend of vegetation changes in Ordos Plateau based on linear trend analysis,standard deviation analysis and analysis of correlation methods by employing MODIS-NDVI data sets of growing season from April to October during 2000-2012 and corresponding meteorological variables including monthly precipitation,temperature and Palmer drought severity index（PDSI）.We studied the correlation between vegetation NDVI and climate change in Ordos Plateau and the effect of drought anomaly changes on vegetation dynamics.The results indicated that the growing season and seasonal vegetation（spring,summer and autumn）NDVI were mainly controlled by the precipitation and drought.At the same time,autumn NDVI was more affected by the summer drought.Further analysis of spatial correlation between NDVI and meteorological factors showed that spring temperature was beneficial to increase spring NDVI pixel in the northern part of Ordos.Summer drought had the strongest correlation with summer NDVI in the desert steppe and desert region.Autumn precipitation had a significant effected on increasing autumn NDVI in the typical steppe.