1982-2015年全球植被变化及其与温度和降水的关系

采用1982-2015年的GLASS-LAI (Global Land Surface Satellite-Leaf Area Index)遥感数据和CRU(Climatic Research Unit)气象数据,利用Mann-Kendall趋势法分析了过去34 a全球9种植被的叶面积指数(Leaf Area Index,LAI)时空变化特征;使用相关分析和逐步线性回归分别探讨了全球9种植被LAI与降水、温度的年际与月关系。结果表明:①全球植被总体呈现绿化趋势,其中变化较大的是草原、稀树草原、常绿阔叶林和多树草原;在植被生长的绿化和褐化趋势中,面积占比最大的植被类型均为草原,说明草原生态系统易受环境因素的影响。②从年际关系看,草原和开放灌丛的LAI与年均降水多呈正相关关系,而温度对不同纬度植被的LAI存在正负2种影响。其原因为温度升高对中低纬度的植被生长有抑制作用,而对高纬度地区植被生长有促进作用。③从年内关系看,南半球降水和温度共同作用于植被的生长;而北半球除常绿阔叶林的生长与温度关系更为紧密外,其它类型植被的生长主要受降水影响。④逐步线性回归结果表明,当月温度的升高对常绿阔叶林、混...

Global Vegetation Change and Its Relationship with Precipitation and Temperature Based on GLASS-LAI in 1982-2015

We analyzed the spatial-temporal changes in global vegetation and their dynamic responses to temperature and precipitation using GLASS-LAI (Global Land Surface Satellite-Leaf Area Index ) and CRU (Climatic Research Unit) meteorological data from 1982 to 2015. The results showed that: 1) Global vegetation showed an overall greening trend, which is paricularly significant over grasslands, savannas, evergreen broadleaf forests and woody savanas. Grasslands have the largest greening and browning area, indicating their vulnerability to climate. 2) In terms of the inter-annual relationships, the LAI of grasslands and open shrublands were overall positively correlated with precipitation, while temperature had different effects on the growth of vegetation at diverse latitudes. This could be attributed to that, the growth of vegetation at middle and low latitudes was inhibited by the increasing temperature, while facilitated by the rising temperature at high latitudes. 3) In terms of the intra-annual relationships, precipitation and temperature together promoted vegetation growth in the southern hemisphere, however, the vegetation in the northern hemisphere was mainly affected by precipitation, except evergreen broadleaf forests. 4) The results of stepwise multiple regression indicated that the rising instant temperature had positive influence on the growth of evergreen broadleaf forests, mixed forests, and croplands, while woody savannas and savannas were significantly impacted by the instant precipitation.