近15年呼伦贝尔沙质草原植被覆盖变化对气候因子的响应

采用2000-2015年呼伦贝尔沙质草原区MODIS NDVI数据，反演该区植被覆盖状况，结合同期6个气象站点的温度和降水量数据，采用线性回归分析、相关与偏相关分析等数理统计方法，探讨植被覆盖变化对气候因子的年际、季节响应特征。结果表明：呼伦贝尔沙质草原植被覆盖较好区域主要集中在陈巴尔虎旗的东北部、鄂温克旗的中东部以及新巴尔虎左旗的东南部区域；近15年间的研究区植被覆盖状况呈逐年波动改善趋势，尤其是2010年后的植被覆盖呈明显改善趋势；2000-2009年间的年均温呈小幅波动的平稳提升趋势，降水则呈不显著降低趋势；而自2010年后，二者的变化趋势正好相反，年均降水量呈显著增加趋势；夏季气温呈不显著降低、降水则呈显著波动增加的年际变化趋势均有利于植被生长；降水是植被覆盖状况最主要的影响因子，气温对植被覆盖的影响也较大。

Responses of Vegetation Changes to Climatic Variations in Hulun Buir Sandy Grassland in the Past 15 Years

MODIS NDVI, temperature and precipitation data of six meteorological sites from 2000 to 2015 were adopted to research vegetation coverage in Hulun Buir sandy grassland area using mathematical statistics method, such as linear regression partial correlation analysis. With the change of vegetation and climate factors with time, it is necessary to investigate the effects of climatic variations (temperature and precipitation) on vegetation changes for a better understanding of vegetation acclimation to climatic changes. NDVI, which can reflect characteristics of plant growth, vegetation coverage, biomass, and so on, is used as an indicator in monitoring vegetation changes. The results show that the better regional vegetation coverage mainly concentrated in the southeast and northeast of the grassland, with a fluctuation but overall improvement trend of during the past 15 years, especially after 2010；the annual average temperature showed a steady improvement trend and the precipitation slightly decreased between 2000 and 2009 in the study area; but the change trend of the two was opposite from 2010, and annual precipitation showed increasing trend; the summer temperature was not significantly reduced, and the precipitation significantly increased. Their changes are conducive to vegetation growth in summer. Precipitation is the main influence factor of vegetation coverage, and the impact of temperature on vegetation coverage is also great.