Modelling of the Evolving Stable Boundary Layer

Sorbjan, Zbigniew

doi:10.1007/s10546-013-9893-z

Cited by 6 publications

(1 citation statement)

References 45 publications

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“…where Ri is the gradient Richardson number, U is the horizontal wind vector, and l is the mixing-length scale. The latter is prescribed using the Blackadar formula (Blackadar 1962) with the maximum asymptotic value l max 5 40 m. It is realized that there exist more physically adequate formulations that were proposed for l and l max (e.g., Delage 1974;Therry and Lacarrère 1983;Van de Wiel et al 2008;Sorbjan 2014). Although simulation results are sensitive to the choice of a closure for l max , this has a minor impact on the main conclusions of the study.…”

Section: Single-column Numerical Modelmentioning

confidence: 99%

Effect of Wind Speed and Leads on Clear-Sky Cooling over Arctic Sea Ice during Polar Night

Chechin

Makhotina

Lüpkes

et al. 2019

Journal of the Atmospheric Sciences

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A simple analytical model of the atmospheric boundary layer (ABL) coupled to sea ice is presented. It describes clear-sky cooling over sea ice during polar night in the presence of leads. The model solutions show that the sea ice concentration and wind speed have a strong impact on the thermal regime over sea ice. Leads cause both a warming of the ABL and an increase of stability over sea ice. The model describes a sharp ABL transition from a weakly stable coupled state to a strongly stable decoupled state when wind speed is decreasing. The threshold value of the transition wind speed is a function of sea ice concentration. The decoupled state is characterized by a large air–surface temperature difference over sea ice, which is further increased by leads. In the coupled regime, air and surface temperatures increase almost linearly with wind speed due to warming by leads and also slower cooling of the ABL. The cooling time scale shows a nonmonotonic dependency on wind speed, being lowest for the threshold value of wind speed and increasing for weak and strong winds. Theoretical solutions agree well with results of a more realistic single-column model and with observations performed at the three Russian “North Pole” drifting stations (NP-35, -37, and -39) and at the Surface Heat Budget of the Arctic Ocean ice camp. Both modeling results and observations show a strong implicit dependency of the net longwave radiative flux at the surface on wind speed.

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Section: Single-column Numerical Modelmentioning

confidence: 99%

Effect of Wind Speed and Leads on Clear-Sky Cooling over Arctic Sea Ice during Polar Night

Chechin

Makhotina

Lüpkes

et al. 2019

Journal of the Atmospheric Sciences

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Gradient-Based Similarity in the Stable Atmospheric Boundary Layer

Sorbjan

2014

Achievements, History and Challenges in Geophysics

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The Extrapolation of Near-Surface Wind Speeds under Stable Stratification Using an Equilibrium-Based Single-Column Model Approach

Optis

Monahan

2016

Journal of Applied Meteorology and Climatology

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Classical approaches to modeling the near-surface (i.e., below 200 m) wind profile are equilibrium based (i.e., no time evolution) and either lack a physical basis or are based on surface-layer physics. In this study, the limits of the equilibrium approach in stable stratification are further tested by applying the method within a more physically comprehensive single-column model (SCM) framework. The SCM considered here is a highly idealized momentum and temperature budget model that uses a range of different parameterizations of turbulent fluxes. A 10-yr observational dataset obtained from the 213-m Cabauw tower in the Netherlands is used to drive the SCM and to assess model performance. Results from this study demonstrate several limitations of this SCM-based equilibrium approach. The existence of two physically meaningful equilibrium solutions for a given value of the surface turbulent temperature flux (used as a lower boundary in the SCM) generally results in either a tendency to underestimate stratification or the breakdown of the model because of runaway cooling and collapsed turbulence. Different representations of the geostrophic wind profile accounting for baroclinic effects caused by the strong land–sea temperature gradient at Cabauw are shown to have only a modest influence on the mean wind profile. The local internal boundary layer (IBL) at Cabauw results in a strong tendency for the SCM to overestimate wind speeds in weakly to moderately stable conditions. In very stable conditions (where the IBL influence was low), the equilibrium approach remained limited because of its inability to account for time-evolving phenomena such as the inertial oscillation and the low-level jet.

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Modelling of the Evolving Stable Boundary Layer

Cited by 6 publications

References 45 publications

Effect of Wind Speed and Leads on Clear-Sky Cooling over Arctic Sea Ice during Polar Night

Effect of Wind Speed and Leads on Clear-Sky Cooling over Arctic Sea Ice during Polar Night

Gradient-Based Similarity in the Stable Atmospheric Boundary Layer

The Extrapolation of Near-Surface Wind Speeds under Stable Stratification Using an Equilibrium-Based Single-Column Model Approach

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