Earth System Modeling and Field Experiments in the Arctic–Boreal Zone

摘要: Climate model calculations performed in the 1980s predicted that the Arctic Ocean and surrounding circumpolar land masses would warm earlier and faster than other parts of the planet as a result of greenhouse gas-‐induced climate change, augmented by the sea-‐ice albedo feedback effect(eg, Manabe and Wetherald, 1975; Hansen et al., 1981; 1984). These predictions have been largely borne out by observations over the last thirty years(eg, Stroeve et al., 2012; Screen and Simmonds, 2010). Nonetheless, climate models vary widely in their warming trajectories over the 21st century. In addition, a range of biogeochemical cycle (BGC) models indicate that Arctic-‐Boreal Zone (ABZ) warming could lead to widespread permafrost thaw, which could contribute around 90 ppm CO2 to the atmospheric CO2 burden by 2100 (Schaefer et al., 2011), and lead to significant changes in the vegetation cover in the ABZ (eg, Lawrence and Slater, 2005). However, the uncertainties associated with these BGC model predictions are even larger than those associated with the physical climate system(PCS) models used to predict climate change.A workshop was held at NASA/GSFC, May 22-‐24 2012, to assess the predictive capability of current Earth system models(ESMs), prioritize the critical science questions and make recommendations regarding new field experiments that would contribute to important improvements in model subcomponents. This report summarizes the findings of the workshop and is intended to provide input to agency program managers and others when deciding on priorities and resource allocations for field experiments in the ABZ as …