基于遥感和气象数据的蒙古高原1982～2013年植被动态变化分析

The Analysis of the Vegetation Dynamic Changes from 1982 to 2013 in the Mongolian Plateau based on Satellite Imageries and Meteorological Data

蒙古高原生态系统及其变化对中国北方乃至整个东北亚的生态安全有着重要影响,了解蒙古高原干旱半干旱区植被生长的动态如何在不同时间和空间尺度上响应气候变化十分必要。利用NDVI数据构建长时间序列,分析植被生长动态变化的过程和时空特征,并与气象数据进行相关性分析。主要结论如下:(1)NDVI的分布具有地带性;(2)大约39.5%的区域NDVI呈显著的增加(P=0.1),7.3%的区域NDVI显著减少(P=0.1),说明植被条件在蒙古高原有所好转;(3)蒙古高原NDVI的变异系数均值16.99%,这表明过去32年里植被覆盖变化情况有较强的波动性;(4)蒙古高原植被的生长状况与降水量有极显著的正相关关系,与气温有极显著的负相关关系。

The Mogolian Plateau （MP） is one of the typical arid regions around the world.The ecosystem of this region and its change have a lot to the areas surrounding the Mogolian Plateau.In particular,the vege- tation system of the Mongolian Plateau plays an important ecological role in northern China and the whole of Northeast Asia. Thus, it is urgent to do research on the vegetation system to see how it has changed throughout these years and detect the trend. In this study, we investigate the spatial-temporal pattern, processes and driver,and the degree and mechanism of grassland dynamics in the MP using the NOAA/ AVHRR 10-day maximum NDVI composite data of 1982~1999 and MODIS 16 day maximum NDVI data of 2000~2013 by building a conversion relationship of them.based on time series analysis methods,we cal- culate the slope of the fitted line of NDVI for each single grid cell,which is set as the indicator of the inten- sity of dynamic changes.Combined with meteorological data,we use the correlation analysis to explore how the natural factors affect the ecosystem.The results show that the temperature, precipitation and the vege- tation are characterizing of zonality in Mongolia Plateau. Non-vegetated area （NDVI〈0.1） and Sparsely vegetated area （0.1〈NDVI〈0.2） account for 7.1% and 22.8% respectively;NDVI significant（p =0.05） increases about 27.0% of this area and significant decreases 7.3% of this area,which indicates the improve- ment of the vegetation system;the average CV of MP is 16.99% ,which means the vegetation cover changes a lot;the area with significant positive correlation of NDVI and precipitation of growing season account for 9.2 % in grassland of the semi-arid area, and significant negative of NDVI and average temperature of grow- ing season account for 14.8G ,mainly in the north of MP.