A dynamic global vegetation model for studies of the coupled atmosphere‐biosphere system

TLDR

The authors develop a new dynamic global vegetation model extending an existing surface‑vegetation‑atmosphere transfer scheme within a coupled ocean‑atmosphere general circulation model. The model simulates photosynthesis, plant and soil respiration, fire, and surface energy exchanges, explicitly represents light competition and sapling establishment, prognostically calculates the full seasonal phenology, and is coupled to the IPSL‑CM4 atmosphere‑ocean‑vegetation system. In global simulations, the model’s carbon and surface energy fluxes match FluxNet observations, and its vegetation distribution, leaf density, carbon stocks, and fluxes agree satisfactorily with measured data.

Abstract

This work presents a new dynamic global vegetation model designed as an extension of an existing surface‐vegetation‐atmosphere transfer scheme which is included in a coupled ocean‐atmosphere general circulation model. The new dynamic global vegetation model simulates the principal processes of the continental biosphere influencing the global carbon cycle (photosynthesis, autotrophic and heterotrophic respiration of plants and in soils, fire, etc.) as well as latent, sensible, and kinetic energy exchanges at the surface of soils and plants. As a dynamic vegetation model, it explicitly represents competitive processes such as light competition, sapling establishment, etc. It can thus be used in simulations for the study of feedbacks between transient climate and vegetation cover changes, but it can also be used with a prescribed vegetation distribution. The whole seasonal phenological cycle is prognostically calculated without any prescribed dates or use of satellite data. The model is coupled to the IPSL‐CM4 coupled atmosphere‐ocean‐vegetation model. Carbon and surface energy fluxes from the coupled hydrology‐vegetation model compare well with observations at FluxNet sites. Simulated vegetation distribution and leaf density in a global simulation are evaluated against observations, and carbon stocks and fluxes are compared to available estimates, with satisfying results.