近30 a青海省植被变化及其气候驱动因子分析

Vegetation Change and Its Driving Climatic Factors in Qinghai Province in Recent 30 Years

基于1982—2013年GIMMS NDVI 3g数据集及青海省50个国家气象观测站同期气象资料,利用趋势分析、相关分析方法,对青海省植被覆盖时空变化特征及其驱动因子进行分析。结果表明:(1)受气候及地形地貌影响,青海省植被覆盖空间差异明显,总体呈现从东南向西北递减趋势。(2)近30 a,青海省气温、降水呈上升趋势,气候由冷干向暖湿化转变。植被覆盖呈现整体升高,局部退化趋势。植被的年代际变化显示,青海省植被覆盖在近30 a呈现增加—减小—再增加的趋势。(3)青海省生长季(4—9月)植被受气温和降水共同影响,除个别站点外,全省NDVI与气温和降水均呈显著正相关关系,与降水相比,NDVI与气温的相关性更强,气温是影响青海省植被变化的主要气候因子。

The spatial and temporal changes of vegetation and its driving climatic factors were studied using the slope analysis and correlation analysis based on the GIMMS NDVI 3g datasets and the meteorological data from 50 meteorological stations in Qinghai Province during the period of 1982-2013. The results showed that the vegetation coverage was diminished from the southeast to the northwest under the effects of climate change and topographical conditions. Under the joint effect of both temperature and precipitation increase,the vegetation coverage was holistically increased from 1982 to 2013 except the degeneration in some small regions in the study area. Interdecadal variation indicated that the vegetation in Qinghai Province was in an increase-decrease-increase trend in recent 30 years. There was a significantly positive correlation between NDVI and climatic factors（ temperature and precipitation） in growing season（ from April to September）. Compared with precipitation,the correlation between NDVI and temperature was higher.