【摘要】 叶面积指数是表征植被冠层特征的重要参数,同时也是决定生态系统净初级生产力的重要因子,它对全球变化和生态系统碳循环研究具有重要意义。目前大范围的叶面积指数只能通过遥感反演和机理模型模拟获得,而通过这两种方法获取的叶面积指数都存在一定的不确定性。利用大气-植被相互作用模型(AVIM2)在0.1°×0.1°经纬度网格上模拟产生了中国区域叶面积指数并与两套使用不同遥感反演方法生成的叶面积指数在空间分布和季节变化特征方面进行了比较。通过比较说明中国区域植被叶面积指数分布主要受水分条件限制,整体呈现东南部高西北部低的趋势。中国区域植被生长的季节变化受季风影响显著,与气温及地表太阳辐射的季节变化趋势相一致。中国区域叶面积指数整体呈现夏季高、春秋季次之而冬季低的趋势。更多还原

【Abstract】 Leaf area index(LAI) is an important parameter to characterize the canopy characteristics.It has significant influence on ecosystem carbon cycle researches since its critical factor to determine ecosystem net primary productivity.The large scale leaf area index can be obtained by both remote sensing reversion and ecosystem modeling though uncertainties exist in the two methods.The atmosphere-vegetation interaction model(AVIM2) was used in this study to generate China-wide leaf area index at the resolution of 0.1 grid degree.The spatial distribution and seasonal cycles of model-generated LAI were compared with two datasets.One is satellite-derived LAI which was deduced by Myneni(1997) based on the physical principles of radiative transfer in vegetation and atmosphere.The other was deduced by Hagemann(2002) based on Advanced Very High Resoulution Radiometer(AVHRR) dataset by using heuristic corrective method.Hagemann′s dataset has being wildly used in general circulation models(GCMs).The comparison shows that the spatial distribution of China′s vegetation LAI is mainly restricted by water conditions,which appears an overall trend of high in southeast and low in northwest.The seasonal cycle of China′s LAI is closely correlated with the monsoon′s movement in a year.It is identical with seasonal variation trends of temperature and surface solar radiation.The seasonal cycle of LAI in China-wide appears a trend of high in summer,moderate in spring and autumn and low in winter.更多还原