Water-Use Efficiency of the Terrestrial Biosphere: A Model Analysis Focusing on Interactions between the Global Carbon and Water Cycles
Water-Use Efficiency of the Terrestrial Biosphere: A Model Analysis Focusing on Interactions between the Global Carbon and Water Cycles
复制标题
DOI：
10.1175/jhm-d-10-05034.1
复制
发表时间：
2012-04-01
影响因子：
3.8
通讯作者：
Inatomi, Motoko
中科院分区：
文献类型：
--
作者：
Ito, Akihiko;Inatomi, Motoko
陆地生态系统的碳循环和水循环密切耦合，水分利用效率（WUE）是生态水文学和生态系统管理的关键参数之一。在这项研究中，陆地生态系统的碳循环和水收支模拟使用的过程为基础的生态系统模型称为植被综合模拟痕量气体（VISIT），和WUE进行了评估：WUEC，定义为总初级生产力（GPP）除以蒸腾量;和WUES，定义为净初级生产力（NPP）除以实际蒸散量。1995-2004年期间，陆地生物圈的年度用水、能源和环境消耗总量估计分别为8.0和0.92克C·千克（-1）H2O。空间上，WUEC和WUES只有弱相关。在北方和高山生态系统中，WUES的范围为1.5 g C kg（-1）H2O。历史模拟表明，从1901年到2005年，生物圈WUE增加（WUEC，+7%; WUES，+12%），主要是由于生产力的增加与大气二氧化碳的增加平行。以国家为基础的分析表明，总的NPP在很大程度上取决于水的可用性，和人类占用的NPP也与水资源在相当大的程度上。这些结果对1）碳循环对预期全球水文变化的响应，2）水收支对陆地碳循环变化的响应，3）基于资源优化利用的生态系统管理具有重要意义。
Carbon and water cycles are intimately coupled in terrestrial ecosystems, and water-use efficiency (WUE; carbon gain at the expense of unit water loss) is one of the key parameters of ecohydrology and ecosystem management. In this study, the carbon cycle and water budget of terrestrial ecosystems were simulated using a process-based ecosystem model called Vegetation Integrative Simulator for Trace Gases (VISIT), and WUE was evaluated: WUEC, defined as gross primary production (GPP) divided by transpiration; and WUES, defined as net primary production (NPP) divided by actual evapotranspiration. Total annual WUEC and WUES of the terrestrial biosphere were estimated as 8.0 and 0.92 g C kg(-1) H2O, respectively, for the period 1995-2004. Spatially, WUEC and WUES were only weakly correlated. WUES ranged from 1.5 g C kg(-1) H2O in boreal and alpine ecosystems. The historical simulation implied that biospheric WUE increased from 1901 to 2005 (WUEC, +7%; WUES, +12%) mainly as a result of the augmentation of productivity in parallel with the atmospheric carbon dioxide increase. Country-based analyses indicated that total NPP is largely determined by water availability, and human appropriation of NPP is also related to water resources to a considerable extent. These results have implications for 1) responses of the carbon cycle to the anticipated global hydrological changes, 2) responses of the water budget to changes in the terrestrial carbon cycle, and 3) ecosystem management based on optimized resource use.