【摘要】 森林生态系统能够有效地吸收大气中的CO2,在一定程度上缓解全球变暖的压力。生态系统固碳能力取决于两个关键因素:NPP的增长强度与碳周转时间。论文通过对遥感监测到的森林生态系统NPP增长趋势进行校正,结合森林样地实测数据得到的碳分配系数与周转时间,建立了中国森林生态系统碳周转模型,并模拟了1982~1999年森林生态系统的碳汇量及其年际变化。结果表明:1982~1999年,我国森林生态系统的平均碳汇量为0.051 PgCa-1,其中植被的碳汇量为0.034 PgCa-1,凋落物的碳汇量为0.013 PgCa-1,土壤的碳汇量为0.004 PgCa-1;不同森林类型中,常绿针叶林和常绿阔叶林的碳汇贡献最大,落叶针叶林和针阔叶混交林贡献最小;进一步分析表明森林植被的固碳效率显著地受到碳周转时间的控制。更多还原

【Abstract】 Forest ecosystem could significantly sequestrate some atmospheric CO2 and,therefore,partly mitigate current pressure on global warming.The carbon sequestration capacity of forest ecosystem is determined by both the NPP increasing trend and carbon turnover time.In order to estimate the capability of forest C sequestration in China,a carbon turnover model based on NPP increasing trend monitored by remote sensing and carbon turnover time derived from forest observed data,was designed.In this model,the maximum light-use efficiency of NPP monitored by remote sensing was revised by plot observed NPP firstly.The revised NPP entered different pools of forest ecosystem according to the ratio of distribution.Some stayed in the carbon pool,while the others decomposed by heterotrophic respiration.The decomposition rate was determined by carbon turnover time.We simulated the carbon sink and annual change of forest ecosystem from 1982 to 1999 in China.Results illustrated that from 1982 to 1999,China forest ecosystem was an apparent carbon sink with a magnitude of 0.051 PgC a-1,in which about 0.034 PgC a-1 in plant tissues,0.013 PgC a-1 in litter fall,and 0.004 PgC a-1 in soil.For different forests,the carbon sinks of ENF and EBF were the largest,while the smallest ones were in DNF and BNMF.The further analysis on carbon sequestration efficiency(CSE) indicated that the CSE value was controlled by carbon turnover time.From largest to smallest,the CSE was ENF>BNMF>EBF>DBF>DNF.更多还原