资源环境科技发展态势分析平台

Precipitation is the largest physical removal pathway of atmospheric reactive organic carbon in the form of dissolved organic carbon (DOC). We present the first global DOC distribution simulated with a global model. A total of 85 and 188 Tg C yr(-1) are deposited to the ocean and the land, respectively, with DOC ranging between 0.1 and 10 mg C L-1 in this GEOS-Chem simulation. We compare the 2010 simulated DOC to a 30 year synthesis of measurements. Despite limited measurements and imperfect temporal matching, the model is able to reproduce much of the spatial variability of DOC (r = 0.63), with a low bias of 35%. We present the global average carbon oxidation state ((OSc) over bar) as a simple metric for describing the chemical composition. In the atmosphere, -1.8 <=(OSc) over bar <= -0.6, and the increase in solubility upon oxidation leads to a global increase in (OSc) over bar in precipitation with -0.6 <=(OSc) over bar (DOC)<= 0.