2000—2015年青海省植被EVI变化趋势及其影响因素分析

Analysis on the Changing Trend of Vegetation EVI and Its Influencing Factors in Qinghai Province from 2000 to 2015

基于2000—2015年青海省MODIS EVI数据,分析了青海省植被EVI的时空变化特征,探讨了人类活动对植被生长发育的影响。结果表明:2000—2015年青海省整体植被EVI呈增加趋势(0.0180/10a),可分为快速增长期(2000—2004年)、波动增长期(2005—2012年)和略微下降期(2013—2015年);EVI呈明显增加的区域面积比例达51.58%,呈明显减少的区域占20.64%,27.78%区域的EVI没有显著变化或基本不变,其中海西州植被EVI增加速率和植被明显改善的面积比例最大。气温和降水与EVI均呈正相关关系,呈正相关的面积比例分别为60.67%和69.50%,降水对植被生长发育的影响略高于气温。载畜量减少和生态工程面积的增加,在一定程度上促进了植被的生长发育,但是与气候变化相比具有局限性和初步性。

Based on the MODIS EVI data of Qinghai Province from 2000 to 2015,this paper analyzed the spatial-temporal change pattern of vegetation EVI in Qinghai Province,and revealed the correlation between climatic factors and vegetation EVI and discussed the effect of human activities on vegetation growth and development. The results showed that the EVI of Qinghai Province increased from 2000 to 2015( 0.0180/10 a),which could be divided into rapid growth period( 2000-2004),fluctuation period( 2005-2012) and slight decline period( 2013-2015); EVI showed a significant increase in the area ratio of51. 58%,showing a significant reduction in the region accounted for 20. 64%,27. 78% of the regional EVI did not significantly change or basically unchanged,of which the increase rate of vegetation EVI and the area of vegetation improvement in Haixi area were the largest. There was a positive correlation between temperature and precipitation and EVI,and the proportion of positive correlation was 60. 67% and 69.50% respectively. The effect of precipitation on vegetation growth and development was slightly higher than that of temperature. The reduction of carrying capacity and the increase of ecological engineering area have promoted the growth and development of vegetation to a certain extent,but it is limited and preliminary compared with climate change.