An Evaluation of the Large-Eddy Simulation Option of the Regional Atmospheric Modeling System in Simulating a Convective Boundary Layer: A FIFE Case Study

Avissar, Roni; Eloranta, E. W.; Gürer, Kemal; Tripoli, Gregory J.

doi:10.1175/1520-0469(1998)055<1109:aeotle>2.0.co;2

Cited by 59 publications

(28 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The other cases show increased ABL heights at the smallest scales of surface heterogeneity, decreasing with the scale. Thus, the temperature seems to be the less sensitive to the impacts of surface heterogeneity than water vapor, which is in contrast to several previous studies which show temperature playing a more dominant role (Avissar et al, 1998;Huang and Margulis, 2009). However, Patton et al (2005) found that this sensitivity depends upon the scale of the surface patches, a result that may be indicative of different transport efficiencies for T and q which varies as a function of both mean wind speed and the spatial scale of surface heterogeneity.…”

Section: Combined Effects Of Surface Heterogeneity and Wind Speed Varcontrasting

confidence: 97%

“…Under moderate winds almost all impacts of surface heterogeneity were reduced. Avissar et al (1998) also found that surface heterogeneity influenced potential temperature much more than humidity. This result led them to conclude that surface patches must be on the order of 5-10 km in order to be significant.…”

Section: Introductionmentioning

confidence: 96%

“…This association leads to the development of a circulation pattern which under light winds become even further weakened, and an alteration of the turbulent profiles (Hadfield et al, 1992). Avissar et al (1998) found the impact of surface heterogeneity on the heat fluxes was reduced particularly for dry conditions under light wind conditions. Under moderate winds almost all impacts of surface heterogeneity were reduced.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Surface heterogeneity impacts on boundary layer dynamics via energy balance partitioning

Brunsell

Mechem

Anderson³

2011

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. The role of land-atmosphere interactions under heterogeneous surface conditions is investigated in order to identify mechanisms responsible for altering surface heat and moisture fluxes. Twelve coupled land surface -large eddy simulation scenarios with four different length scales of surface variability under three different horizontal wind speeds are used in the analysis. The base case uses Landsat ETM imagery over the Cloud Land Surface Interaction Campaign (CLASIC) field site for 3 June 2007. Using wavelets, the surface fields are band-pass filtered in order to maintain the spatial mean and variances to length scales of 200 m, 1600 m, and 12.8 km as lower boundary conditions to the model (approximately 0.25, 1.2 and 9.5 times boundary layer height). The simulations exhibit little variation in net radiation. Rather, there is a pronounced change in the partitioning of the surface energy between sensible and latent heat flux. The sensible heat flux is dominant for intermediate surface length scales. For smaller and larger scales of surface heterogeneity, which can be viewed as being more homogeneous, the latent heat flux becomes increasingly important. The simulations showed approximately 50 Wm −2 difference in the spatially averaged latent heat flux. The results reflect a general decrease of the Bowen ratio as the surface conditions transition from heterogeneous to homogeneous. Air temperature is less sensitive to variations in surface heterogeneity than water vapor, which implies that the role of surface heterogeneity may be to maximize convective heat fluxes through modifying and maintaining local temperature gradients. More homogeneous surface conditions (i.e. smaller length scales), on the other hand, tend to maximize latent heat flux. The intermediate scale (1600 m) this does not hold, and is a more complicated interaction of scales.Correspondence to: N. A. Brunsell (brunsell@ku.edu) Scalar vertical profiles respond predictably to the partitioning of surface energy. Fourier spectra of the vertical wind speed, air temperature and specific humidity (w,T andq) and associated cospectra (wT ,wq andTq), however, are insensitive to the length scale of surface heterogeneity, but the near surface spectra are sensitive to the mean wind speed.

show abstract

Section: Combined Effects Of Surface Heterogeneity and Wind Speed Varcontrasting

confidence: 97%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Surface heterogeneity impacts on boundary layer dynamics via energy balance partitioning

Brunsell

Mechem

Anderson³

2011

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Several LES applications have demonstrated the ability of the technique to reproduce canonical turbulence pro®les in the horizontally homogeneous ABL [25,26,4,29]. Several other recent applications have explored the eect of observed heterogeneous surface conditions on overall boundary layer development [18,36,5]. This paper extends the use of LES into an exploration of blending layers over patchy surfaces with distinct and abrupt transitions in surface temperature, wetness, and roughness.…”

Section: Large Eddy Simulationmentioning

confidence: 92%

Natural integration of scalar fluxes from complex terrain

Albertson

Parlange

1999

Advances in Water Resources

174

104

View full text Add to dashboard Cite

Large eddy simulations of turbulent¯ow and transport in the atmospheric boundary layer were conducted over heterogeneous sources of heat and water vapor to identify the blending properties of the turbulent mixing in an unstably strati®ed boundary layer. The numerical simulations show that the concept of blending in the ABL is in fact a useful one, even under convective conditions, for a range of surface conditions. Since the transport eddies that are responsible for the blending have sizes that are constrained by the boundary layer depth, and since the vertical motion is so important under the unstable density strati®cation studied here, we see that when the length scales of the source variability on the land surface become signi®cantly greater than the ABL depth the blending is lost. In this case the source ®elds remain relatively uncoupled by the important eddy motion. However, for smaller surface length scales, the dynamic eddy motion couples the surface patches. Hence, there is good reason that the land surface exchange phenomenon would not be scale invariant over the entire range of scales. Because of the active role of temperature the eects of inhomogeneous surface sources of sensible heat persist higher into the ABL than do the eects of surface sources from more passive scalars, such as water vapor. Moreover, the mean ®elds of potential temperature and speci®c humidity blend at much lower heights than do the vertical turbulent¯ux ®elds of these two scalars. We propose a useful measure of blending eciency for simulation studies and show how this bridges from the dynamics responsible for the blending to the horizontal homogeneity of scalar¯ux ®elds at measurement heights in the ABL. Ó

show abstract

“…Simulations have also been conducted at the large eddy scale (e.g. Avissar et al 1998;Jiang & Cotton 2000). Further applications involve coupling the meteorology from RAMS with chemical models (Berkowitz et al 1999), hydrological models (Avissar & Pan 2000), and biophysical models (Walko et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Statistical comparison of Regional Atmospheric Modelling System forecasts with observations

Buckley

Weber

2004

Meteorological Applications

View full text Add to dashboard Cite

show abstract

An Evaluation of the Large-Eddy Simulation Option of the Regional Atmospheric Modeling System in Simulating a Convective Boundary Layer: A FIFE Case Study

Cited by 59 publications

References 45 publications

Surface heterogeneity impacts on boundary layer dynamics via energy balance partitioning

Surface heterogeneity impacts on boundary layer dynamics via energy balance partitioning

Natural integration of scalar fluxes from complex terrain

Statistical comparison of Regional Atmospheric Modelling System forecasts with observations

Contact Info

Product

Resources

About