Simulating the carbon cycling of northern peatlands using a land surface scheme coupled to a wetland carbon model (CLASS3W-MWM)

Northern peatlands store approximately one-third of the terrestrial soil carbon (C), although they cover only 3% of the global land mass Northern peatlands can be subdivided into bogs and fens based on their hydrology and biogeochemistry Peatland hydrology and biogeochemistry are tightly coupled to climate and, therefore, may be very sensitive to climate variability and change To address the fate of the large peatland soil C storage under a future changed climate, a peatland C model, the McGill Wetland Model (MWM), was coupled to a land surface climate model (the wetland version of the Canadian Land Surface Scheme, CLASS3W), referred as CLASS3W-MWM We evaluated the CLASS3W-MWM for a bog (Mer Bleue, located at 45 41°N, 75 48°W, in eastern Canada) and a poor fen (Degerö Stormyr, located at 64°11′N, 19°33′E, in northern Sweden) CLASS3W-MWM captured the magnitude and direction of the present day C cycling very well for both bogs and fens Moreover, the seasonal and interannual variability were reproduced reasonably well Root mean square errors (RMSE) were 0 8 for the components of net ecosystem production (NEP) for both the Mer Bleue bog and the Degerö Stormyr fen The performance of the coupled model for both bog and fen is similar to that of the stand-alone MWM driven by observed weather rather than simulated surface and soil climate This modelling study suggests that northern peatlands are hydrologically and thermally con