Controls on evapotranspiration at a subarctic sedge fen

• Published in: Hydrological Processes
• Main Authors: Eaton, Andrea K., Rouse, Wayne R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Hudson; Hudson Bay; Subarctic
• Online Access: http://dx.doi.org/10.1002/hyp.1029; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fhyp.1029; https://onlinelibrary.wiley.com/doi/pdf/10.1002/hyp.1029

Abstract In this study, 10 years (1990–99) of summertime data collected at a representative sedge fen in the Hudson Bay Lowland (HBL) are used to investigate the energy and water balance dynamics of subarctic wetlands. The summertime climatic characteristics at the study site during the 10 year study period are also examined. It is shown that mean cumulative summertime precipitation P avg for the study decade closely approximates the 30 year mean P avg . However, the mean summertime air temperature T avg for the study decade is 1 °C higher than the 30 year mean T avg . To examine the energy and water balance dynamics at the study site, the variation in each of their respective components throughout the study decade is considered. Little variation is observed in cumulative summertime net radiation $Q^{*}_{\rm cum}$ and cumulative summertime ground heat flux Q Gcum however, substantial year‐to‐year variation is evident in cumulative summertime water deficit WD cum , cumulative summertime precipitation P cum , cumulative summertime sensible heat flux Q Hcum , and cumulative summertime latent heat flux Q Ecum . It is noted that the variability in Q Ecum is particularly significant because it consumes the largest proportion of the available summertime energy, and is the largest component of the summertime water balance at this subarctic wetland. Past research has suggested that Q *, P , and T have the most influence on summertime Q E at high‐latitude wetlands. To test this hypothesis at our study site, Q Ecum , P cum , T avg and $Q^{*}_{\rm cum}$ from each year in the study decade were examined. It is observed that high Q Ecum is associated with high P cum , T avg and $Q^{*}_{\rm cum}$ , and that low Q Ecum is associated with low P cum and T avg . To identify the hydroclimatological variables that are most responsible for controlling Q Ecum dynamics at the sedge fen, a stepwise linear regression was performed. This analysis indicates that P cum and $Q^{*}_{\rm cum}$ are the most important hydroclimatological ...