The Spatial and Temporal Variations of the Turbulent Fluxes of Heat, Momentum and Water Vapor over Lake Ontario

Bean, B. R.; Emmanuel, C. B.; Gilmer, R. O.; Megavin, R. E.

doi:10.1175/1520-0485(1975)005<0532:tsatvo>2.0.co;2

Cited by 15 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Despite a vapour saturated surface boundary, a downward humidity gradient appears to have developed when the water surface was colder than the air (Figure 3). Similar vapour gradients occur over snowpacks (Burns et al, 2014) or lake surfaces in spring (Bean, Emmanuel, Gilmer, & Megavin, 1975;Blanken et al, 2000) where the surface temperature can lag air temperature by many months, often resulting in net condensation. In the present study, it is unclear where condensate nucleation occurs-on water, on vegetation, or as fog over the surface.…”

Section: Evaporation Ratesmentioning

confidence: 85%

Evaporation and the subcanopy energy environment in a flooded forest

Allen

Reba

Edwards

et al. 2017

Hydrological Processes

View full text Add to dashboard Cite

The combination of tree canopy cover and a free water surface makes the subcanopy environment of flooded forested wetlands unlike other aquatic or terrestrial systems. Subcanopy vapour fluxes and energy budgets represent key controls on water level and understorey climate but are not well understood. In a permanently flooded forest in south‐eastern Louisiana, USA, an energy balance approach was used to address (a) whether evaporation from floodwater under a forest canopy is solely energy limited and (b) how energy availability was modulated by radiation and changes in floodwater heat storage. A 5‐month continuous measurement period (June–November) was used to sample across seasonal changes in canopy activity and temperature regimes. Over this period, the subcanopy airspace was humid, maintaining saturation vapour pressure for 28% of the total record. High humidity coupled with the thermal inertia of surface water altered both seasonal and diel energy exchanges, including atypical phenomena such as frequent day‐time vapour pressure gradients towards the water surface. Throughout the study period, nearly all available energy was partitioned to evaporation, with minimal sensible heat exchange. Monthly mean evaporation ranged from 0.7 to 1.7 mm/day, peaking in fall when canopy senescence allowed greater radiation transmission; contemporaneous seasonal temperature shifts and a net release of stored heat from the surface water resulted in energy availability exceeding net radiation by 30% in October and November. Relatively stable energy partitioning matches Priestley–Taylor assumptions for a general model of evaporation in this ecosystem.

show abstract

Section: Evaporation Ratesmentioning

confidence: 85%

Evaporation and the subcanopy energy environment in a flooded forest

Allen

Reba

Edwards

et al. 2017

Hydrological Processes

View full text Add to dashboard Cite

show abstract

“…The major shortcomings of the other mass transfer approaches are their dependency on overwater measurements (MT3 and MTS) and the dubious figures of excessive condensation (MT1 and MT4). In addition, spatial patterns of wind speed, dew point, and latent heat flux, computed as a byproduct of the MT2 program, were valid in comparison with more sophisticated soundings of the air over the lake by aircraft by Bean et al [1975] Improvements in the estimates of evaporation may be accomplished with the development of better adjustment factors for generating meteorological fields over the lake. Additional work also should be carried out to perfect the technique of estimating water temperature data from satellite imagery on an operational basis.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of evaporation from Lake Ontario during IFYGL by a modified mass transfer equation

Phillips¹

1978

Water Resources Research

View full text Add to dashboard Cite

Daily evaporation from Lake Ontario during the International Field Year for the Great Lakes (April 1972 to March 1973) was computed by a modified mass transfer technique. Turbulent energy flux was calculated by using upwind !and station data and the surface water temperature at 88 grid points on the lake. Wind speed and humidity at each grid point were determined through multiregression equations that take into account stability, fetch, and water temperature. Daily, monthly, and annual evaporation amounts obtained in this study are compared to amounts obtained by conventional mass transfer, energy balance, and terrestrial water budget methods. Discrepancies in the results of the various approaches are examined and discussed. INTRODUCTION One of the objectives of the International FieldYear for the Great Lakes (IFYGL) was to improve current formulations used to estimate evaporation from large, temperate lakes. Several projects were designed to arrive at independent estimates of time-averaged lake evaporation for periods ranging from 1 day to 1 month. Evaporation from Lake Ontario was compared (1) as a residual in the water budget, (2) as a residual in the energy budget, (3) from an atmospheric water budget for the autumn season of the year, (4) from aerodynamic equations applied to meteorological buoy data, and (5) from mass transfer formulae. This paper describes details of a modified mass transfer technique in which regression equations requiring fetch and surface water temperature over that fetch, as well as the thermodynamic variables, are used to estimate the flux at a number of grid points over the lake. The spatial distribution and temporal variation of the turbulent energy flux, i.e., sensible and latent, from large lakes are important information useful for forecasting mesoscale phenomena such as lake effect snowstorms and lake-land breeze circulations and for predicting the time and extent of ice formation and dissipation for specific locations. In addition, a more accurate estimate of water loss would improve predictions of lake level fluctuations. To this end, comparisons are made with the results of a number of approaches to determine evaporation from Lake Ontario during IFYGL. M^ss TR^SSFER: L^iCE H•FS•R FORMULAOne indirect method of computing evaporation consists of a modified application of Dalton's law, where evaporation is considered to be a function of the wind speed and the difference between the vapor pressure of saturated air at the water surface and the vapor pressure of the overriding air. Many variants of the Dalton formulation have been developed to compute evaporation, and these are frequently referred to as mass transfer equations. The terms 'bulk aerodynamic' or 'bulk transfer' have also been used.

show abstract

“…is to be commended for publishing a clear account of the daily evaporation from Lake Ontario during the International Field Year for the Great Lakes (IFYGL) as calculated from the modified mass transfer method (MT2). This has eased comparison of lakewide averaged daily evaporation from the MT2 method with that determined from NOAA's gust probe system aboard a DC-6 aircraft [Bean et al, 1975]…”

Section: Phillipsmentioning

confidence: 99%

The Spatial and Temporal Variations of the Turbulent Fluxes of Heat, Momentum and Water Vapor over Lake Ontario

Cited by 15 publications

References 0 publications

Evaporation and the subcanopy energy environment in a flooded forest

Evaporation and the subcanopy energy environment in a flooded forest

Evaluation of evaporation from Lake Ontario during IFYGL by a modified mass transfer equation

Comment on ‘Evaluation of evaporation from lake ontario during IFYGL by a modified mass transfer equation’ by David W. Phillips

Contact Info

Product

Resources

About