Evaluation and model impacts of alternative boundary-layer height formulations
- 964 Downloads
We study bulk formulations for the boundary-layer height which are currently in use for atmospheric modelling. The formulations are based on various forms of the Richardson number, and these are evaluated with Cabauw field data in stable conditions. Results for both a large-eddy simulation model and anE-ε turbulence closure model for neutral boundary layers are also utilised. An updated formulation is introduced, which combines the effects of shear in the outer region of the boundary layer with surface friction. The updated formulation has a better performance for neutral boundary layers with upper level stratification. The findings are illustrated with a single-column model for a case with relatively high winds over the tropical ocean including shallow cumulus convection, and for a case with fair weather over land. We also show that for stable conditions, the updated formulation performs better than estimates on the basis of surface friction alone.
KeywordsBoundary Layer Richardson Number Stable Boundary Layer Cumulus Convection Turbulence Closure Model
Unable to display preview. Download preview PDF.
- Fouquart, Y. and Bonnell, B.: 1980, ‘Computation of Solar Heating of the Earth’s Atmosphere: A New Parameterization’,Beitr. Phys. Atmosph. 53, 35–62.Google Scholar
- Hack, J.: 1994, ‘Parameterization of Moist Convection in the NCAR Community Climate Model, CCM2’,J. Geophys. Res. 99, 5551–5568.Google Scholar
- Holland, J. Z. and Rasmusson, E. M.: 1973, ‘Measurement of Atmospheric Mass, Energy and Momentum Budgets over a 500 km Square of Tropical Ocean’,Mon. Wea. Rev. 101, 44–55.Google Scholar
- Kim, J. and Mahrt, L.: 1992, ‘Simple Formulation of Turbulent Mixing in the Stable Free Atmosphere and Nocturnal Boundary Layer’,Tellus 44A, 381–394.Google Scholar
- Koracin, D. and Berkowicz, R.: 1988, ‘Nocturnal Boundary-Layer Height: Observations by Acoustic Sounders and Predictions in Terms of Surface-Layer Parameters’,Boundary-Layer Meteorol. 43, 65–83.Google Scholar
- van Ulden, A. P. and Holtslag, A. A. M.: 1985, ‘Estimation of Atmospheric Boundary Layer Parameters for Diffusion Applications’,Boundary-Layer Meteorol. 24, 1196–1207.Google Scholar