Integrated Biosphere Simulator Model (IBIS), Version 2.5

The Integrated Biosphere Simulator (or IBIS) is designed to be a comprehensive model of the terrestrial biosphere. Tthe model represents a wide range of processes, including land surface physics, canopy physiology, plant phenology, vegetation dynamics and competition, and carbon and nutrient cycling. The model generates global simulations of the surface water balance (e.g., runoff), the terrestrial carbon balance (e.g., net primary production, net ecosystem exchange, soil carbon, aboveground and belowground litter, and soil CO2 fluxes), and vegetation structure (e.g., biomass, leaf area index, and vegetation composition). IBIS was developed by Center for Sustainability and the Global Environment (SAGE) researchers as a first step toward gaining an improved understanding of global biospheric processes and studying their potential response to human activity [Foley et al. 1996]. IBIS was constructed to explicitly link land surface and hydrological processes, terrestrial biogeochemical cycles, and vegetation dynamics within a single, physically consistent framework. Furthermore, IBIS was one of a new generation of global biosphere models, termed Dynamic Global Vegetation Models (or DGVMs), that consider transient changes in vegetation composition and structure in response to environmental change. Previous global ecosystem models have typically focused on the equilibrium state of vegetation and could not allow vegetation patterns to change over time. Version 2.5 of IBIS includes several major improvements and additions [Kucharik et al. 2000]. SAGE continues to test the performance of the model, assembling a wide range of continental- and global-scale data, including measurements of river discharge, net primary production, vegetation structure, root biomass, soil carbon, litter carbon, and soil CO2 flux. Using these field data and model results for the contemporary biosphere (1965-1994), their evaluation shows that simulated patterns of runoff, NPP, biomass, leaf area index, soil carbon, and total soil CO2 flux agreed reasonably well with measurements that have been compiled from numerous ecosystems. These results also compare favorably to other global model results [Kucharik et al. 2000].

综合生物圈模拟器（Integrated Biosphere Simulator，简称IBIS）是一款专为全面表征陆地生物圈而开发的模型。该模型涵盖了地表物理学、冠层生理学、植物物候、植被动态与种间竞争、碳与养分循环等多类核心过程。该模型可开展地表水平衡（如径流）、陆地碳平衡（如净初级生产力（Net Primary Production, NPP）、净生态系统交换（Net Ecosystem Exchange, NEE）、土壤碳、地上与地下凋落物及土壤CO₂通量）以及植被结构（如生物量、叶面积指数（Leaf Area Index, LAI）与植被组成）的全球模拟。IBIS由全球可持续性与环境中心（Center for Sustainability and the Global Environment，简称SAGE）的研究人员开发，作为加深对全球生物圈过程理解、探究其对人类活动潜在响应的初步探索[Foley等，1996]。IBIS在单一物理自洽的框架内，实现了地表与水文过程、陆地生物地球化学循环以及植被动态的显式联结。此外，IBIS属于新一代全球生物圈模型——动态全球植被模型（Dynamic Global Vegetation Models，简称DGVMs），这类模型可模拟植被组成与结构响应环境变化的瞬态演变过程。此前的全球生态系统模型通常仅聚焦于植被的平衡态，无法实现植被格局随时间的动态变化。IBIS 2.5版本包含多项重大改进与功能新增[Kucharik等，2000]。SAGE持续对该模型的性能开展验证，汇集了大量大陆及全球尺度的实测数据，涵盖河流流量、净初级生产力、植被结构、根系生物量、土壤碳、凋落物碳与土壤CO₂通量等观测指标。借助这些野外实测数据与1965-1994年当代生物圈的模拟结果，其评估显示，径流、净初级生产力（NPP）、生物量、叶面积指数、土壤碳及总土壤CO₂通量的模拟格局与从众多生态系统汇编得到的实测数据吻合度较好。该结果同样优于其他全球模型的模拟结果[Kucharik等，2000]。