Surface energy balance of the western and central Canadian subarctic : Variations in the energy balance among five major terrain types

Abstract In this study, the surface energy balance of 10 sites in the western and central Canadian subarctic is examined. Each research site is classified into one of five terrain types (lake, wetland, shrub tundra, upland tundra, and coniferous forest) using dominant vegetation type as an indicator of surface cover. Variations in the mean summertime values (15 June–25 August) of the energy balance partitioning, Bowen ratio (β), Priestley–Taylor alpha (α), and surface saturation deficit (Do) are compared within and among terrain types. A clear correspondence between the energy balance characteristics and terrain type is found. In addition, an evaporative continuum from relatively wet to relatively dry is observed among terrain types. The shallow lake and wetland sites are relatively wet with high QE/Q* (latent heat flux/net radiation), high α, low β, and low Do values. In contrast, the upland tundra and forest sites are relatively dry with low QE/Q*, low α, high β, and high Do values.

[1]  P. Lafleur,et al.  Water Loss from the Floor of a Subarctic Forest , 1994 .

[2]  W. Rouse,et al.  Soil heat flux in permafrost: Characteristics and accuracy of measurement , 1987 .

[3]  Comparative surface energy budgets in western and central subarctic regions of Canada , 2000 .

[4]  J. D. Smith,et al.  The Effect of Weather Variability on the Energy Balance of a Lake in the Hudson Bay Lowlands, Canada , 1990, Arctic and Alpine Research.

[5]  W. Brutsaert.  Evaporation into the atmosphere , 1982 .

[6]  K. E. Moore,et al.  Turbulent transports over tundra , 1992 .

[7]  F. Chapin,et al.  Subgrid-scale variability in the surface energy balance , 1998 .

[8]  David Bolton.  The Computation of Equivalent Potential Temperature , 1980 .

[9]  J. Monteith,et al.  Boundary Layer Climates. , 1979 .

[10]  I. S. Bowen.  The Ratio of Heat Losses by Conduction and by Evaporation from any Water Surface , 1926 .

[11]  W. Rouse.  Microclimate of Arctic Tree Line 2. Soil Microclimate of Tundra and Forest , 1984 .

[12]  Robert B. Stewart,et al.  Evaporation in high latitudes , 1977 .

[13]  P. Marsh,et al.  EVAPORATION FROM MACKENZIE DELTA LAKES, N.W.T., CANADA , 1988 .

[14]  K. E. Moore,et al.  A season of heat, water vapor, total hydrocarbon, and ozone fluxes at a subarctic fen , 1994 .

[15]  K. E. Moore,et al.  Growing season water balance at a boreal jack pine forest , 2000 .

[16]  Rouse Wr,et al.  Factors affecting the summer carbon dioxide budget of subarctic wetland tundra , 1996 .

[17]  P. Blanken,et al.  The role of willow-birch forest in the surface energy balance at arctic treeline , 1994 .

[18]  Roger A. Pielke,et al.  Land–atmosphere energy exchange in Arctic tundra and boreal forest: available data and feedbacks to climate , 2000, Global change biology.

[19]  H. Ritchie,et al.  The Mackenzie GEWEX study : The Water and Energy cycles of a major North American River basin , 1998 .

[20]  P. Blanken,et al.  Carbon dioxide fluxes in a northern fen during a hot, dry summer , 1998 .

[21]  L. Gay,et al.  Tests of a robust eddy correlation system for sensible heat flux , 1992 .

[22]  W. Rouse,et al.  Progress in hydrological research in the Mackenzie GEWEX study , 2000 .

[23]  W. Rouse,et al.  A Comparison of Sensible and Latent Heat Flux Calculations Using the Bowen Ratio and Aerodynamic Methods , 1989 .

[24]  W. Rouse,et al.  Impact of Hudson Bay on the energy balance in the Hudson Bay Lowlands and the potential for climatic modification , 1985 .

[25]  T. A. Black,et al.  Determination of Forest Evapotranspiration Using Bowen Ratio and Eddy Correlation Measurements , 1979 .

[26]  W. Rouse,et al.  Energy balance differences and hydrologic impacts across the northern treeline , 1992 .

[27]  Rouse Wr,et al.  The role of individual terrain units in the water balance of wetland tundra , 1995 .

[28]  P. Blanken,et al.  Modelling evaporation from a high subarctic willow-birch forest , 1995 .

[29]  W. J. Shuttleworth,et al.  Comparative measurements of the energy fluxes over a pine forest , 1975 .

[30]  P. Lafleur.  Annual Variability in Summer Evapotranspiration and Water Balance at a Subarctic Forest Site , 1994 .

[31]  Philip Marsh,et al.  Eddy covariance measurements of evaporation from Great Slave Lake, Northwest Territories, Canada , 2000 .

[32]  Robert B. Stewart,et al.  A simple method for determining the evaporation from shallow lakes and ponds , 1976 .

[33]  R. Simpson.  On The Computation of Equivalent Potential Temperature , 1978 .

[34]  Philip Marsh,et al.  MELTWATER FLUXES AT AN ARCTIC FOREST-TUNDRA SITE , 1996 .

[35]  B. Hicks,et al.  A comparison of turbulence measurements by different instruments; Tsimlyansk field experiment 1970 , 1973 .

[36]  C. J. Moore.  Eddy flux measurements above a pine forest , 1976 .

[37]  P. Bartlett,et al.  Water and carbon dioxide exchange at a boreal young jack pine forest in the BOREAS northern study area , 1999 .

[38]  D. S. Rawson.  The Physical Limnology of Great Slave Lake , 1950 .

[39]  Peter M. Lafleur,et al.  Energy balance and evapotranspiration from a subarctic forest , 1992 .

[40]  M. G. Ryan,et al.  Magnitudes and seasonal patterns of energy, water, and carbon exchanges at a boreal young jack pine forest in the BOREAS northern study area , 1997 .

[41]  F. Chapin,et al.  Surface Energy Balance on the Arctic Tundra: Measurements and Models , 1999 .

[42]  S. Wofsy,et al.  Controls on Evaporation in a Boreal Spruce Forest. , 1999 .

[43]  K. E. Moore,et al.  Growing season boundary layer climate and surface exchanges in a subarctic lichen woodland , 1994 .

[44]  W. Rouse.  Microclimate at Arctic Tree Line 3. The Effects of Regional Advection on the Surface Energy Balance of Upland Tundra , 1984 .

[45]  W. Rouse,et al.  Energy partitioning at treeline forest and tundra sites and its sensitivity to climate change , 1995 .

[46]  C. J. Moore.  Frequency response corrections for eddy correlation systems , 1986 .

[47]  W. Rouse,et al.  The energy balance in the coastal environment of James Bay and Hudson Bay during the growing season , 1987 .

[48]  W. Rouse,et al.  The influence of surface cover and climate on energy partitioning and evaporation in a subarctic wetland , 1988 .

[49]  W. Oechel,et al.  Characteristics of energy and water budgets over wet sedge and tussock tundra ecosystems at North Slope in Alaska , 1998 .

[50]  F. Chapin,et al.  A Comparative Approach to Regional Variation in Surface Fluxes Using Mobile Eddy Correlation Towers , 1997 .

[51]  C. Priestley,et al.  On the Assessment of Surface Heat Flux and Evaporation Using Large-Scale Parameters , 1972 .

[52]  W. Rouse,et al.  ADVECTION IN THE COASTAL HUDSON BAY LOWLANDS, CANADA. I. THE TERRESTRIAL SURFACE ENERGY BALANCE , 1991 .