A comparison of boundary layer diffusion schemes in unstable conditions over land

Holtslag, A.A.M.; Meijgaard, E. van; Rooy, Wim C. de

doi:10.1007/bf00710891

Cited by 68 publications

(46 citation statements)

References 19 publications

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“…From an algebraic solution of eight revised diagnostic equations, Blackadar (1979) obtained flux-gradient relations to parameterise the turbulent heat and momentum flux as well as the Richardson number for stable, neutral, and unstable conditions. Apart from the basic turbulence scheme, there are a number of additional options in MALTE for the eddy diffusivity parameterisation, based on semi-empirical and ad-hoc profile methods, such as those proposed by Holtslag et al (1995), Lüpkes and Schlünzen (1996), Degrazia et al (1997aDegrazia et al ( , b, 1998Degrazia et al ( , 2001. In all of them, the mixing height z i serves as a characteristic length scale in the convective boundary layer (CBL).…”

Section: Eddy Diffusivity Parameterizationmentioning

confidence: 99%

MALTE – model to predict new aerosol formation in the lower troposphere

et al. 2006

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Abstract. The manuscript presents a detailed description of the meteorological and chemical code of Malte -a model to predict new aerosol formation in the lower troposphere. The aerosol dynamics are achieved by the new developed UHMA (University of Helsinki Multicomponent Aerosol Model) code with kinetic limited nucleation as responsible mechanism to form new clusters. First results indicate that the model is able to predict the on-and offset of new particle formation as well as the total aerosol number concentrations that were in good agreement with the observations. Further, comparison of predicted and measured H 2 SO 4 concentrations showed a satisfactory agreement. The simulation results indicated that at a certain transitional particle diameter (2-7 nm), organic molecules can begin to contribute significantly to the growth rate compared to sulphuric acid. At even larger particle sizes, organic molecules can dominate the growth rate on days with significant monoterpene concentrations. The intraday vertical evolution of newly formed clusters and particles in two different size ranges resulted in two maxima at the ground. These particles grow around noon to the detectable size range and agree well with measured vertical profiles.

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Section: Eddy Diffusivity Parameterizationmentioning

confidence: 99%

MALTE – model to predict new aerosol formation in the lower troposphere

et al. 2006

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“…First-order closure is based on diagnostic flux gradient relations, i.e., the fluxes are represented by the downgradient approach, eventually semi-empirically corrected for countergradient flows. For the eddy diffusivity of scalars one can either use an ad hoc approach (e.g., O'Brien, 1970), diagnostic relations based on diagnostic flux equations (Holtslag and Moeng, 1991;Holtslag et al, 1995) or semi-empirical expressions based on the turbulence spectrum, such as proposed and evaluated, e.g., by Degrazia et al (1997aDegrazia et al ( ,b, 1998Degrazia et al ( , 2001 the flow characteristics, e.g., on atmospheric stability (see Subsection 5.1). However, the present approach opens a suitable way to investigate turbulence-related NPF.…”

Section: Alternative Approachesmentioning

confidence: 99%

Columnar modelling of nucleation burst evolution in the convective boundary layer – first results from a feasibility study Part I: Modelling approach

Hellmuth

2006

Atmos. Chem. Phys.

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Abstract.A high-order modelling approach to interpret "continental-type" particle formation bursts in the anthropogenically influenced convective boundary layer (CBL) is proposed. The model considers third-order closure for planetary boundary layer turbulence, sulphur and ammonia chemistry as well as aerosol dynamics. In Paper I of four papers, previous observations of ultrafine particle evolution are reviewed, model equations are derived, the model setup for a conceptual study on binary and ternary homogeneous nucleation is defined and shortcomings of process parameterisation are discussed. In the subsequent Papers II, III and IV simulation results, obtained within the framework of a conceptual study on the CBL evolution and new particle formation (NPF), will be presented and compared with observational findings.

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“…The case study by Holtslag et al (1995) examined ABL model runs driven by observed surface fluxes, and reproduced the observed boundary-layer structure for a case study at Cabauw reasonably well. But in coupled landsurface -ABL model runs they found that they could not reproduce observed fluxes and boundary-layer structure using a simpler land surface scheme.…”

Section: Introductionmentioning

confidence: 71%

Evaluation of a land-surface scheme at Cabauw

Holtslag

2004

Theor. Appl. Climatol.

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SummaryWe study the response of the land-surface to prescribed atmospheric forcing for 31 May 1978 at Cabauw, Netherlands, using the land-surface scheme from the Coupled Atmospheric boundary layer-Plant-Soil (CAPS) model. Results from model runs show realistic daytime surface fluxes are produced using a canopy conductance formulation derived from Cabauw data (for 1987, a different year), and un-tuned parameterizations of root density (nearuniform with depth) and soil heat flux (reduced thermal conductivity through vegetation). Sensitivity of modelcalculated surface heat fluxes to initial values of soil moisture is also examined. Results of this study provide the land-surface 'base state' for a coupled land-atmosphere modeling study.

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A comparison of boundary layer diffusion schemes in unstable conditions over land

Cited by 68 publications

References 19 publications

MALTE – model to predict new aerosol formation in the lower troposphere

MALTE – model to predict new aerosol formation in the lower troposphere

Columnar modelling of nucleation burst evolution in the convective boundary layer – first results from a feasibility study Part I: Modelling approach

Evaluation of a land-surface scheme at Cabauw

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