Methane emissions from a wetland region within the Hudson Bay Lowland: An atmospheric approach

摘要: Continuous observations of methane (CH4) mixing ratios in combination with the atmospheric 222Rn activity and stable isotope carbon hydrogen CH4 at a remote midcontinental monitoring station Fraserdale, Ontario (49°53′N, 81°34′W) are used to characterize quantify regional emissions from Hudson Bay Lowland (HBL). Large diurnal variations observed both trace substances during summer which due ground level sources accumulating strong nocturnal inversions. Diurnal changes isotopic composition Fraserdale were determine signature wetland source be δ13CVPDB = (−60.0±3.2)‰ δDVSMOW (−442±142)‰. These integrated values regarded as representative several hundred square kilometers. The daughter made months September October 1994–1996 estimate total emission rates region Fraserdale. fluxes for (11.5±1.2) mg m−2 d−1 (4.7±2.7) d−1, respectively, an estimated absolute uncertainty ±30%. well comparable flux measurements performed 1990 NOWES campaign using static chambers [Roulet et al., 1994] eddy correlation on tall tower [Edwards 1994].