Impacts of the new land surface physics and vegetation dynamics on the the GFDL AGCM simulation of climate.

Results of simulations with the GFDL's atmospheric model AM2 coupled with the new dynamic land model LM3V are compared with the results of the standard configuration of the AM2/LM2 model and available observations. LM3V combines land-surface and dynamic vegetation model. It simulates long-term vegetation and carbon pool dynamics, as well as fast time-scale physical interactions between the land surface and the atmosphere, such as exchange of water, energy, and carbon. The simulation is compared against a control run with the traditional land surface scheme (LM2), using specified potential vegetation distribution. The results of the simulations are examined with the emphasis on the time-average changes in surface and atmospheric climate and its' variability. Additionally, we examine the impact of the biosphere-atmosphere feedback processes including water-carbon coupling through transpiration and photosynthesis and changes in the land surface characteristics due to climate variability.