Study of Radiative and Turbulent Processes in the Stable Boundary Layer under Weak Wind Conditions

Gopalakrishnan, Sundararaman; Sharan, Maithili; McNider, Richard T.; Singh, Madan Pal

doi:10.1175/1520-0469(1998)055<0954:soratp>2.0.co;2

Cited by 35 publications

(36 citation statements)

References 14 publications

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“…This underlines that processes other than turbulent diffusion become more important when the wind drops. Gopalakrishnan et al (1998). For the last night we note that the cooling rates are large, especially considering the fact that the boundary layer is thin.…”

Section: B) Vertical Profilesmentioning

confidence: 89%

“…Tjemkes, 1988) showed that the output from several emissivity models can differ (approximately 10 Wm -2 ) from those of line-by-line models near the surface (Gopalakrishnan et al, 1998), the latter giving the most accurate results. However, the grey-body approach is computationally more efficient.…”

Section: B) Radiationmentioning

confidence: 99%

“…For very stable (weak wind) conditions and during the day-night transition, radiative flux divergence significantly influences the SBL structure (mainly by decreasing the inversion strength) in governing the atmospheric cooling rate near the surface as shown by Funk (1960), André and Mahrt (1982), Garratt and Brost (1981, hereafter GB81), Nkedirim (1978Nkedirim ( , 1988, Gopalakrishnan et al (1998) and discussed by Andreas (2002). The coupling between the lower atmosphere and the land surface is of major importance, especially under very stable conditions (Deardorff, 1976;Best, 1998 andVan de Wiel, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Modeling the Evolution of the Atmospheric Boundary Layer Coupled to the Land Surface for Three Contrasting Nights in CASES-99

Steeneveld

Wiel

Holtslag

2006

Journal of the Atmospheric Sciences

112

124

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The modeling and prediction of the stable boundary layer over land is a persistent problematic feature in weather, climate and air quality topics. Here, the performance of a state-of-the-art single column boundary-layer model is evaluated with observations from the CASES-99 field experiment. Very high model resolution in the atmosphere and the soil is utilized to represent three different stable boundary-layer archetypes, namely: a fully turbulent night, an intermittently turbulent night and a radiative night with hardly any turbulence (all at clear skies). Each archetype represents a different class of atmospheric stability. In the current model, the atmosphere is fully coupled to a vegetation layer and the underlying soil. In addition, stability functions (local scaling) are utilized based on local observations. Overall it is found that the vertical structure, the surface fluxes (apart from the intermittent character) and the surface temperature in the stable boundary layer can be satisfactorily modeled for a broad stability range (at a local scale) with our current understanding of the physics of the stable boundary layer. This can also be achieved by the use of a rather detailed coupling between the atmosphere and the underlying soil and vegetation, together with high resolution in both the atmosphere and the soil. This is especially true for the very stable nights, where longwave radiative cooling is dominant. Both model outcome and observations show that in the latter case the soil heat flux is a dominant term of the surface energy budget.3

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Section: B) Vertical Profilesmentioning

confidence: 89%

Section: B) Radiationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling the Evolution of the Atmospheric Boundary Layer Coupled to the Land Surface for Three Contrasting Nights in CASES-99

Steeneveld

Wiel

Holtslag

2006

Journal of the Atmospheric Sciences

112

124

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“…To study the impact of wind speed on the results (e.g., Estournel and Guedalia 1985;Derbyshire 1999;Gopalakrishnan et al 1998), additional runs are done with a reduced geostrophic wind (see below). Note that it is not our intention to do a full parameter study here.…”

Section: Model Parameter Settingsmentioning

confidence: 99%

“…In addition, the surface temperature and the surface heat flux are interdependent and are strongly related to the magnitude of the geostrophic wind (e.g. Estournel and Guedalia 1985;Gopalakrishnan et al 1998;Derbyshire 1999;Delage et al 2002;van de Wiel et al 2003;Steeneveld et al 2006a, b). Thus neither the surface temperature nor the surface heat flux, is a true external boundary condition, at least not for stable conditions (van de Wiel et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Role of land-surface temperature feedback on model performance for the stable boundary layer

Holtslag

Steeneveld

Wiel

2007

Boundary-Layer Meteorol

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At present a variety of boundary-layer schemes is in use in numerical models and often a large variation of model results is found. This is clear from model intercomparisons, such as organized within the GEWEX Atmospheric Boundary Layer Study (GABLS). In this paper we analyze how the specification of the land-surface temperature affects the results of a boundary-layer scheme, in particular for stable conditions. As such we use a well established column model of the boundary layer and we vary relevant parameters in the turbulence scheme for stable conditions. By doing so, we can reproduce the outcome for a variety of boundary-layer models. This is illustrated with the original set-up of the second GABLS intercomparison study using prescribed geostrophic winds and land-surface temperatures as inspired by (but not identical to) observations of CASES-99 for a period of more than two diurnal cycles. The model runs are repeated using a surface temperature that is calculated with a simple land-surface scheme. In the latter case, it is found that the range of model results in stable conditions is reduced for the sensible heat fluxes, and the profiles of potential temperature and wind speed. However, in the latter case the modelled surface temperatures are rather different than with the original set-up, which also impacts on near-surface air temperature and wind speed. As such it appears that the model results in stable conditions are strongly influenced by non-linear feedbacks in which the magnitude of the geostrophic wind speed and the related land-surface temperature play an important role.Keywords Atmosphere-land interaction · Boundary-layer parameter study · GABLS · Model evaluation · Model intercomparison study · Land-surface temperature feedback · Stable boundary layer

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Large‐eddy simulation of very stable boundary layers. Part I: Modeling methodology

Chinita

Matheou

Miranda

2022

Quart J Royal Meteoro Soc

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The large‐eddy simulation of very stable boundary layers (SBLs) remains challenging due to the large anisotropy of turbulent motions resulting from buoyancy suppression effects, and to the general reduction of its energetic scales. Here, we develop a novel large‐eddy simulation model setup to enable the modeling of the very SBL, avoiding the use of the Monin–Obukhov similarity theory at its lower boundary condition, as it breaks down in these conditions in agreement with previous studies. The new approach requires very fine grids in the vertical direction, in the order of a few centimeters. A series of Ekman‐layer‐type boundary layers under weak‐wind conditions (unormalg=1$$ {u}_{\mathrm{g}}=1 $$ and 2 m·$$ \cdotp $$sprefix−1$$ {}^{-1} $$), and strong surface cooling rates (1 and 3 K·$$ \cdotp $$hrprefix−1$$ {}^{-1} $$) at high latitude is studied using isotropic grids of 0.05 and 0.10 m resolution. The low‐order statistics show some sensitivity to the grid resolution; for example, both the SBL height and the low‐level jet position decrease with increasing grid resolution. In general, some differences are spotted regarding the shape of the wind speed and temperature vertical profiles, compared with weakly to moderately stratified conditions, suggesting that the structure and characteristics of the SBL evolve with increasing stratification. Moreover, the wind turning is significant from the surface, where the surface wind angle relative to the geostrophic wind is about 50°$$ {}^{\circ} $$. Lastly, two regimes within very stable conditions can be qualitatively identified primarily based on the gradient Richardson number (Ri$$ Ri $$) profiles: In the less stable regime, Ri$$ Ri $$ increases almost linearly with height and a quasi‐steady state is achieved; however, in the most stable regime, Ri$$ Ri $$ sharply increases near the surface and remains constant throughout the SBL while increasing with time up to Riprefix≈0.4$$ Ri\approx 0.4 $$. Thus, a quasi‐steady state is not achieved; and although turbulence does not collapse, it remains weak.

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Study of Radiative and Turbulent Processes in the Stable Boundary Layer under Weak Wind Conditions

Cited by 35 publications

References 14 publications

Modeling the Evolution of the Atmospheric Boundary Layer Coupled to the Land Surface for Three Contrasting Nights in CASES-99

Modeling the Evolution of the Atmospheric Boundary Layer Coupled to the Land Surface for Three Contrasting Nights in CASES-99

Role of land-surface temperature feedback on model performance for the stable boundary layer

Large‐eddy simulation of very stable boundary layers. Part I: Modeling methodology

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