Arctic Summer Surface Energy Balance at Two Coastal Drained Lake Basins, Barrow, Alaska
Abstract
We examined the partitioning of the summer surface energy balance at two coastal drained lake basins using measurements from two eddy covariance towers in Barrow, Alaska. Drained lake basins are a common land feature covering approximately one fourth of the Arctic Coastal Plain but have been given limited attention. Overall, wetlands are extensive in the region in spite of an annual precipitation close to a desert and a negative summer P-ET. Included in the analysis was summer 2007, which experienced unusually high air temperatures and low precipitation compared to the long term mean. During the five analyzed summers, most of the energy available at the ground surface was partitioned into sensible heat flux despite saturated or nearly saturated near-surface soils. The maritime conditions resulted in a cool and close to saturated air mass with a few exceptions on individual days. With a ground surface often warmer than the air above and limited air vapor pressure deficits, the dissipation of the available heat at the ground surface was mainly partitioned into sensible heat flux resulting in midday Bowen Ratios (sensible divided by latent heat flux) above unity. Total daily latent heat flux presented in mm of water varied between 0.2 - 4.2 mm/day with a Jun-Aug mean of 1.5 mm. In 80% of the analyzed days, mean midday evapotranspiration occurred below the equilibrium rate resulting in a Priestley-Taylor alpha value below unity. The equilibrium evaporation rates of inland arctic wetlands have previously shown to occur at or above equilibrium rate. Further, the energy balance partitioning of a wetland located in a maritime or continental climate show differences such as in the Bowen Ratio. It is therefore necessary to analyze coastal and inland areas separately when examining the hydrological response of wetlands to climate changes.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.B13A0420L
- Keywords:
-
- 0475 Permafrost;
- cryosphere;
- and high-latitude processes (0702;
- 0716);
- 0497 Wetlands (1890);
- 0764 Energy balance;
- 1818 Evapotranspiration;
- 1843 Land/atmosphere interactions (1218;
- 1631;
- 3322)