• Andreas, E. L., , and Decosmo J. , 2002: The signature of sea spray in the HEXOS turbulent heat flux data. Bound.-Layer Meteor., 103 , 303333.

  • Baldocchi, D. D., , and Hutchinson B. A. , 1987: Turbulence in an almond orchard: Vertical variations in turbulent statistics. Bound.-Layer Meteor., 20 , 127146.

    • Search Google Scholar
    • Export Citation
  • Bates, N. R., , and Merlivat L. , 2001: The influence of short-term wind variability on air–sea CO2 exchange. Geophys. Res. Lett., 28 , 32813284.

  • Blanken, P. D., and Coauthors. 2000: Eddy covariance measurements of evaporation from Great Slave Lake, Northwest Territories, Canada. Water Resour. Res., 36 , 10691077.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Blanken, P. D., , Black T. A. , , Neumann H. H. , , den Hartog G. , , Yang P. C. , , Nesic Z. , , and Lee X. , 2001: The seasonal water and energy exchange above and within a boreal aspen forest. J. Hydrol., 245 , 118136.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Drennan, W. M., , Kahma K. K. , , and Donelan M. A. , 1999: On momentum and velocity spectra over waves. Bound.-Layer Meteor., 92 , 489515.

  • Finnigan, J. J., 1979: Turbulence in waving wheat. II: Structure of momentum transfer. Bound.-Layer Meteor., 16 , 213236.

  • Heikinheimo, M., , Kangas M. , , Tourula T. , , Venäläinen A. , , and Tattari S. , 1999: Momentum and heat fluxes over lakes Tämnaren and Råksjö determined by the bulk-aerodynamic and eddy-correlation methods. Agric. For. Meteor., 98 , –99. 521534.

    • Search Google Scholar
    • Export Citation
  • Hudson, E., 1991: Marine Guide to Local Conditions and Forecasts: Great Slave Lake, Lake Athabasca, Lake Winnipeg, Lake of the Woods, Lake Nipigon. Ministry of Supply and Services, 130 pp.

    • Search Google Scholar
    • Export Citation
  • Kaimal, J. C., , and Finnigan J. J. , 1994: Atmospheric Boundary Layer Flows: Their Structure and Measurement. Oxford University Press, 289 pp.

    • Search Google Scholar
    • Export Citation
  • Laird, N. G., , and Kristovich D. A. R. , 2002: Variations of sensible and latent heat fluxes from a Great Lakes buoy and associated synoptic weather patterns. J. Hydrometeor., 3 , 312.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Miyake, M., , Donelan M. , , McBean G. , , Paulson C. , , Badgely F. , , and Leavitt E. , 1970: Comparison of turbulent fluxes over water determined by profile and eddy correlation techniques. Quart. J. Roy. Meteor. Soc., 96 , 132137.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pond, S., , Phelps G. T. , , and Paquin J. E. , 1971: Measurements of the turbulent fluxes of momentum, moisture and sensible heat over the ocean. J. Atmos. Sci., 28 , 901917.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rawson, D. S., 1950: The physical limnology of Great Slave Lake. J. Fish. Res. Can., 8 , 366.

  • Renfrew, I. A., , and Moore G. W. K. , 1999: An extreme cold-air outbreak over the Labrador Sea: Roll vortices and air–sea interactions. Mon. Wea. Rev., 127 , 23792394.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rouse, W. R., and Coauthors. 2003a: Energy and water cycles in a high-latitude north-flowing river system. Bull. Amer. Meteor. Soc., 84 , 7387.

  • Rouse, W. R., , Oswald C. M. , , Binyamin J. , , Blanken P. D. , , Schertzer W. M. , , and Spence C. , 2003b: Interannual and seasonal variability of the surface energy balance and temperature of central Great Slave Lake. J. Hydrometeor., 4 , 720730.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Russell, L. M., , Leschow D. H. , , Laursen K. K. , , Krummel P. B. , , Siems S. T. , , Bandy A. R. , , Thornton D. C. , , and Bates T. S. , 1998: Bidirectional mixing in an ACE 1 marine boundary layer overlain by a second turbulent layer. J. Geophys. Res., 103 , 1641116432.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schertzer, W. M., , Rouse W. R. , , and Blanken P. D. , 2000: Cross-lake variation of physical limnological and climatological processes of Great Slave Lake. Phys. Geogr., 21 , 385406.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schertzer, W. M., , Rouse W. R. , , Blanken P. D. , , and Walker A. E. , 2003: Over-lake meteorology and estimated bulk heat exchange of Great Slave Lake in 1998 and 1999. J. Hydrometeor., 4 , 649659.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schuepp, P. H., , Leclerc M. Y. , , MacPherson J. I. , , and Desjardins R. L. , 1990: Footprint prediction of scalar fluxes from analytical solutions of the diffusion equations. Bound.-Layer Meteor., 50 , 355373.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shuttleworth, W. J., , Gash J. H. C. , , Lloyd C. R. , , McNeil D. D. , , Moore C. J. , , and Wallace J. S. , 1988: An integrated micrometeorological system for evaporation measurement. Agric. For. Meteor., 43 , 295317.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Smith, S. D., 1974: Eddy flux measurements over Lake Ontario. Bound.-Layer Meteor., 6 , 235255.

  • Stewart, R. E., and Coauthors. 1998: The Mackenzie GEWEX Study: The water and energy cycles of a major North American river basin. Bull. Amer. Meteor. Soc., 79 , 26652683.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sun, J. L., and Coauthors. 2002: Intermittent turbulence associated with a density current passage in the stable boundary layer. Bound.-Layer Meteor., 105 , 199219.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Thom, A. S., 1975: Momentum, mass and heat exchange of plant communities. Principles, J. L. Monteith, Ed., Vol. 1, Vegetation and the Atmosphere, Academic Press, 57–109.

    • Search Google Scholar
    • Export Citation
  • Walker, A., , Silis A. , , Metcalf J. , , Davey M. , , Brown R. , , and Goodison B. , 1999: Snow cover and lake ice determination in the MAGS region using passive microwave satellite and conventional data. Proc. Fourth Scientific Workshop for the Mackenzie GEWEX Study (MAGS), Montreal, QC, Canada, NSERC and AES, Environment Canada, 89–91.

    • Search Google Scholar
    • Export Citation
  • Weckwerth, T. M., , Horst T. W. , , and Wilson J. W. , 1999: An observational study of the evolution of horizontal convective rolls. Mon. Wea. Rev., 127 , 21602179.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wyngaard, J. C., , and Coté O. R. , 1972: Cospectral similarity in the atmospheric surface layer. Quart. J. Roy. Meteor. Soc., 98 , 590603.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 168 168 9
PDF Downloads 50 50 9

Enhancement of Evaporation from a Large Northern Lake by the Entrainment of Warm, Dry Air

View More View Less
  • 1 Department of Geography and Program in Environmental Studies, University of Colorado, Boulder, Colorado
  • | 2 School of Geography and Geology, McMaster University, Hamilton, Ontario, Canada
  • | 3 National Water Research Institute, Burlington, Ontario, Canada
© Get Permissions
Restricted access

Abstract

The turbulent exchange of water vapor and heat were measured above Great Slave Lake, Northwest Territories, Canada, using the eddy covariance method for most of the ice-free period in 1997, 1998, and 1999. In all years, evaporation tended to occur in episodic pulses, lasting 52–78 h, between which quiescent periods dominated. The contributions of these evaporation pulses to the measured total evaporation were 45%, 65%, and 47% for 1997, 1998, and 1999, respectively, yet occurred on only 24% (1997), 37% (1998), and 25% (1999) of the total number of days observed. Despite the suppression of turbulent mixing, due to the stable atmospheric conditions that dominated much of the ice-free periods, analyses of high-frequency wind, air temperature, and humidity data revealed that evaporation was enhanced by the mixing of warm, dry air down to the lake surface. Conditional sampling of turbulent measurements showed that these sweeps of warm, dry air were infrequent, yet were the dominant turbulent transfer mechanism. Because the approximately 3-day-long evaporation pulses were composed of an aggregation of sweeps, measurements of air–lake turbulent heat exchange needed to be made at a high frequency in order to capture these significant events. Implications of climate variability on the mechanisms that control short- and long-term evaporation rates were discussed, in terms of the positive feedback that developed between entrainment and evaporation.

Corresponding author address: Peter D. Blanken, Department of Geography and Program in Environmental Studies, University of Colorado, 260 UBC, Boulder, CO 80309-0260. Email: blanken@colorado.edu

Abstract

The turbulent exchange of water vapor and heat were measured above Great Slave Lake, Northwest Territories, Canada, using the eddy covariance method for most of the ice-free period in 1997, 1998, and 1999. In all years, evaporation tended to occur in episodic pulses, lasting 52–78 h, between which quiescent periods dominated. The contributions of these evaporation pulses to the measured total evaporation were 45%, 65%, and 47% for 1997, 1998, and 1999, respectively, yet occurred on only 24% (1997), 37% (1998), and 25% (1999) of the total number of days observed. Despite the suppression of turbulent mixing, due to the stable atmospheric conditions that dominated much of the ice-free periods, analyses of high-frequency wind, air temperature, and humidity data revealed that evaporation was enhanced by the mixing of warm, dry air down to the lake surface. Conditional sampling of turbulent measurements showed that these sweeps of warm, dry air were infrequent, yet were the dominant turbulent transfer mechanism. Because the approximately 3-day-long evaporation pulses were composed of an aggregation of sweeps, measurements of air–lake turbulent heat exchange needed to be made at a high frequency in order to capture these significant events. Implications of climate variability on the mechanisms that control short- and long-term evaporation rates were discussed, in terms of the positive feedback that developed between entrainment and evaporation.

Corresponding author address: Peter D. Blanken, Department of Geography and Program in Environmental Studies, University of Colorado, 260 UBC, Boulder, CO 80309-0260. Email: blanken@colorado.edu

Save