Current Steps - New Required PFTs

1. Current Steps - New Required PFTs • Start with CLM-DGVM based on LPJ (Cook et al. 2008) • 5 boreal/arctic PFTs • Boreal Needleleaf Tree, Boreal Broadleaf Tree, Temperate Broadleaf Tree, C3 Arctic Grass. C3 Grass • Additional PFTs to address Circumarctic Vegetation • Forbs, sedges, prostrate shrub, dwarf-erect shrub, tall shrub, mosses, lichens • Sensitivity of CCSM to vegetation cover exercise with current, paleo-climate, an potential future vegetation Circumarctic Vegetation Classification for Biogeographical Modeling and Paleo-Validation

2. Future Steps • Proposed new PFTs are equivalent to the “species” used in the individual or agent-based model based on ArcVeg to be incoporated into CLM-CN: • Computationally based on nitrogen mass balance, as N is thought to be the key limiting nutrient in many tundra ecosystems • Simulates the effects freeze-thaw disturbances and herbivore grazing in addition to standard carbon-nitrogen biogeochemistry • Adapt ArcVeg nitrogen dynamics to enhance CLM-CN dynamics, • Couple vegetation dynamics to improved soil permafrost physics and associated decomposition • Use agent based model in uncoupled and coupled simulations