Magnitude and seasonality of wetland methane emissions from the Hudson Bay Lowlands (Canada)

摘要: Abstract. The Hudson Bay Lowlands (HBL) is the second largest boreal wetland ecosystem in world and an important natural source of global atmospheric methane. We quantify HBL methane emissions by using GEOS-Chem chemical transport model to simulate aircraft measurements over from ARCTAS pre-HIPPO campaigns May–July 2008, together with continuous 2004–2008 surface observations at Fraserdale (southern edge HBL) Alert (Arctic background). difference concentrations between shown be a good indicator emissions, implies sharp seasonal onset late May (consistent data), peak July–August, shut-off September. model, which variation emission mainly driven temperature, reproduces well summer but its shoulders are too broad. suggest that this reflects suppression snow cover greatly improve simulation accounting for effect. Our resulting best estimate 2.3 Tg a−1, several-fold higher than previous estimates (Roulet et al., 1994; Worthy 2000).