Annual and seasonal variability in evapotranspiration and water table at a shrub-covered bog in southern Ontario, Canada

摘要: Evapotranspiration (ET) was measured via the eddy covariance technique at a shrub bog peatland in southeastern Ontario for 5 years. For most of study period temperature above normal. Precipitation variable, but, 2 years, late summer dry periods resulted an extended deep drawdown water table (WT). Growing-season (May–September) daily ET varied considerably; maximum rates were 4 to mm day−1. Winter order magnitude smaller than summer, yet total winter loss important, accounting 23 30% annual loss. Annual precipitation exceeded by 1·55 1·94 times. During growing season, closely related potential evaporation (PET); however, slope this relationship statistically different some In contrast, and WT only weakly When sorted into cm classes there no difference mean across classes; two deepest had significantly ET. The ratio ET/PET followed same pattern. We present conceptual model that relates WT, soil hydraulic properties moss vascular plant processes. Copyright © 2005 John Wiley & Sons, Ltd.