藏北地区2005-2015年间植被覆盖变化及其对气候变化的响应

Vegetation Coverage Change and Its Response to Climate Change in Northern Tibet from 2005 to 2015

为了厘清藏北植被覆盖变化的趋势及其对气候变化的响应特征,利用2005-2015年间的MODIS-NDVI遥感数据、温度和降水量数据,采用最大值合成法、变异指数的计算、Slope趋势分析、相关性分析以及偏相关性分析方法,对藏北地区的月NDVI、季NDVI以及年均NDVI的变化特征进行探讨分析.并对这11年间的植被覆盖趋势的变化进行监测,同时研究了植被覆盖变化与气温与降水量之间的相关性.得到结论如下:(1)2005-2015年间植被覆盖呈单峰型,植被的覆盖具有季节性,对季节变化敏感;藏北地区植被覆盖呈降低的趋势,有特定的生长季,植被覆盖变化从研究区的西北部向东南部呈现增加的趋势.(2)藏北地区气温呈波动性上升,降水量有波动,呈小幅度的下降,总体气候朝着暖湿方向发展;植被覆盖变化与气候因子(温度和降水量)呈正相关性.这一分析论证可为藏北地区生态环境保护提供科学性的建议以及理论支撑.

In order to characterize the trend of vegetation coverage change and its response to climate change in northern Tibet,MODIS-NDVI remote sensing data,temperature and precipitation data from 2005 to 2015 were used to analyze the monthly NDVI,quarterly NDVI,and annual NDVI variation characteristics in it by using maximum value synthesis,variation index calculation,slope trend analysis,correlation analysis and partial correlation analysis.The changes in vegetation coverage trends over the 11-year period were monitored,and the correlation between the changes and temperature and precipitation was studied.The conclusions are mainly as follows:(1)The vegetation coverage was unimodal and seasonal and sensitive to seasonal changes between 2005-2015.There is a tendency for vegetation coverage to decrease in northern Tibet,with specific growing seasons.Vegetation coverage change shows an increasing trend from the northwest to the southeast of the study area.(2)Temperatures in northern Tibet are fluctuating and rising,precipitation is fluctuating and decreasing slightly,and the overall climate is developing in the direction of warmth and humidity.Vegetation coverage changes are positively correlated with climatic factors(temperature and precipitation).This analysis and demonstration can provide scientific suggestions and theoretical support for ecological and environmental protection in northern Tibet.