全球变化与陆地系统综合集成模拟——新一代陆地生态系统动态模型(DLEM)

The Dynamic Land Ecosystem Model (DLEM) for Simulating Terrestrial Processes and Interactions in the Context of Multifactor Global Change

人类社会从陆地生态系统获取生产和生活资料的同时也作为一种干扰形式改变着地气之间的动态平衡。这三个既独立又相互耦合的子系统共同组成了一个复杂的陆地系统。如何深入理解这一系统的过程和机制是人类应对气候变化挑战的前提条件。陆地生态系统模型作为一种集成工具,已广泛应用于全球变化研究的各个领域,但从输入数据到模型结构和过程等诸多方面仍存在很大的不确定性。近年来,随着大气和地面生态观测网络的不断完善以及遥感等空间技术的不断强大,使陆地生态系统模型进一步发展和突破成为可能。新一代多因子驱动的陆地生态系统动态模型(DynamicL and Ecosystem Model,DLEM)正是在这一背景下应运而生的。本文旨在介绍DLEM的主体框架、输入输出变量、关键过程、主要功能和特点。

The Dynamic Land Ecosystem Model （DLEM） was developed to meet critical needs for understanding and predicting the large-scale patterns and processes of terrestrial ecosystems and continental margins, and complex interactions among climate, ecosystem and human in the context of multifactor global change. The DLEM couples major biophysical, biogeochemical, vegetation dynamical and land use processes, and works at multiple scales in time step ranging from daily to yearly and spatial resolution from meters to kilometers, from region to globe. The DLEM is characterized by the following features： 1） multiple factors driven; 2） fully-coupled cycles of carbon, nitrogen and water; 3） concurrently simulation of major greenhouse gases （CO2, CH4, N2O, H2O）; 4） dynamically tracking changes in land cover/use and vegetation distribution. The model has been validated against site-specific measurements across the globe and applied at various scales. In this paper, we have briefly addressed model structure, parameters, key processes and major input/output variables. As a case study, we presented the simulated global fluxes of net primary productivity, evapotranspiration and methane during 1948-2005 and their spatial patterns in the year 2000. We also identified major gaps in terrestrial ecosystem modeling and field observations, and further discussed some critical future research needs.