Phenology and growth of different vegetation types in the Ent Dynamic Global Terrestrial Ecosystem Model (DGTEM)

The Ent Dynamic Global Terrestrial Ecosystem Model (DGTEM), is a new DGTEM for coupling the fluxes of water, energy, carbon and nitrogen between land surface and climate models, for simulating seasonal growth and decay of vegetation, and for simulating decadal- to century-scale vegetation cover change. This study shows the use of Fluxnet data in evaluating vegetation phenology, carbon allocation, and growth in the Ent DGTEM in both stand-alone mode and coupled mode to GISS Land Surface Model (LSM), and the performance of the coupled model at the global scale forced by Global Soil Wetness Project-2 (GSWP2) meteorology. Ecosystem types modeled include temperature broadleaf cold-deciduous forest at Harvard Forest, MA, and Morgan Monroe State Forest, IN; drought-senescent Mediterranean oak/annual grass savanna at Tonzi Ranch, CA, and annual grassland at Vaira Ranch, CA; and radiation phenology of tropical rainforest in Tapajos National Forest, Brazil. Site-level simulations forced with Fluxnet meterological data are evaluated by comparing the simulated leaf area index (LAI), carbon stocks in plant carbon pools, and carbon and water fluxes between land and the atmosphere against observational data. Global-scale simulations forced with GSWP2 data for 1986 to 1995 are performed to answer the question of whether the model, well-constrained against the local observations over the limited number of years, extrapolates well to global scales and captures interannual variation over the course of 10 years.