Abstract
In numerical weather prediction, climate and hydrologicalmodelling, the grid cell size is typically larger than the horizontal length scales of variations in aerodynamicroughness, surface temperature and surface humidity. These local land cover variations give rise to sub-gridscale surface flux differences. Especially the roughness variations can give a significantly differentvalue between the equilibrium roughness in each of the patches as compared to the aggregated roughness value,the so-called effective roughness, for the grid cell. The effective roughness is a quantity that secures thephysics to be well-described in any large-scale model. A method of aggregating the roughness step changesin arbitrary real terrain has been applied in flat terrain (Denmark) where sub-grid scale vegetation-drivenroughness variations are a dominant characteristic of the landscape. The aggregation model is a physicaltwo-dimensional atmospheric flow model in the horizontal domain based on a linearized version of theNavier Stoke equation. The equations are solved by the Fast Fourier Transformation technique, hence the codeis very fast. The new effective roughness maps have been used in the HIgh Resolution Limited Area Model(HIRLAM) weather forecasting model and the weather prediction results are compared for a number of casesto synoptic and other observations with improved agreement above the predictions based on currentstandard input. Typical seasonal springtime bias on forecasted winds over land of +0.5 m s-1 and-0.2 m s-1 in coastal areas is reduced by use of the effective roughness maps.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Andersen, H. V., Hovmand, M. F., Hummelshøj, P., and Jensen, N. O.: 1993, 'Measurements of Ammonia Flux to a Spruce Stand in Denmark', Atmos. Environ. Part A-Gen. Topics 27, 189-202.
Avissar, R.: 1991, 'A Statistical-Dynamic Approach to Parameterize Sub-Grid-Scale Land-Surface Heterogeneity in Climate Models', Surv. Geophys. 12, 155-178.
Bastiaanssen, W. G. M., Menenti, M., Feddes, R. A., and Holtslag, A. A. M.: 1998a, 'A Remote Sensing Surface Energy Balance Algorithm for Land (SEBAL)-1. Formulation', J. Hydrol. 213, 198-212.
Bastiaanssen, W. G. M., Pelgrum, H., Wang, J., Ma, Y., Moreno, J. F., Roerink, G. J., and van der Wal, T.: 1998b, 'A Remote Sensing Surface Energy Balance Algorithm for Land (SEBAL)-2. Validation', J. Hydrol. 213, 213-229.
Batchvarova, E., Gryning, S. E., and Hasager, C. B.: 2001, 'Regional Fluxes of Momentum and Sensible Heat over a Sub-Arctic Landscape during Late Winter', Boundary-Layer Meteorol. 99, 489-507.
Beljaars, A. C. M., Schotanus, P., and Nieuwstadt, F. T. M.: 1983, 'Surface-Layer Similarity under Nonuniform Fetch Conditions', J. Clim. Appl. Meteorol. 22, 1800-1810.
Boegh, E., Schelde, K., and Soegaard, H.: 2000, 'Estimating Transpiration Rates in a Danish Agricultural Area Using Lands at Thermal Mapper Data', Phys. Chem. Earth, Part B-Hydrol. Oceans Atmos. 25, 685-689.
Christensen, J. H., Christensen, O. B., Lopez, P., van Meijgaard, E., and Botzet, M.: 1996, The HIRHAM4 Regional Atmospheric Climate Model, DMI Scientific Report 96-4. [Available from DMI, Lyngbyvej 100, Copenhagen Ø, Denmark.]
Christensen, J. H., Christensen, O. B., Schulz, J.-P., Hagemann, S., and Botzet, M.: 2001, High Resolution Physiographic Data Set for HIRHAM4: An Application to a 50 Km Horizontal Resolution Domain Covering Europe, Danish Meteorological Institute. Technical Report 01-15, pp. 1-21.
Claussen, M.: 1991, 'Estimation of Areally-Averaged Surface Fluxes', Boundary-Layer Meteorol. 54, 387-410.
Claussens, M.: 1995, 'Estimation of Regional Heat and Moisture Fluxes in Homogeneous Terrain with Bluff Roughness Elements', J. Hydrol. 166, 353-369.
Cuxart, J., Bougeault, P., and Redelsperger, J. L.: 1995, 'Turbulence Closure for a Non-Hydrostatic Model', in 12th AMS Symposium on Boundary-Layer Turbulence, pp. 409-412.
Cuxart, J., Bougeault, P., and Redelsperger, J. L.: 2000, 'A Turbulence Scheme Allowing for Meso-Scale and Large-Eddy Simulations', Quart. J. Roy. Meteorol. Soc. 126, 1-30.
Danish Areal Information System: 2001, 1:25.000, 2000, Miljø-og Energiministeriet-Fremstillet at Danmarks Miljøgelser, see http://www.dmu.dk/1_viden/2_miljoetilstand/ 3_samfund/ais/index_en.htm
de Bruin, H. A. R., Bink, N. J., and Kroon, L. J. M.: 1991, 'Fluxes in the Surface Layer under Advective Conditions', in J. J. Schmugge and J.-C. André (eds.), Land Surface Evaporation, Springer-Verlag, New York, pp. 157-170.
Dellwik, E. and Jensen, N. O.: 2000, 'Internal Equilibrium Layer Growth over Forest', Theor. Appl. Climatol. 66, 173-184.
Dickinson, R. E., Henderson-Sellers, A., Kennedy, P. J., and Wilson, M. F.: 1986, Biosphere-Atmosphere Transfer Scheme (BATS) for the NCAR Community ClimateModel, NCAR Technical Note, NCAR/TN275+STR, Boulder, CO, 69 pp.
EEA: 1992, CORINE Land Cover, A European Community Project, European Environment Agency Task-Force, Directorate General for the Environment, Nuclear Safety and Civil Protection. Commission of the European Communities.
Gash, J. H. C.: 1986, 'A Note on Estimating the Effect of a Limited Fetch on Micrometeorological Evaporation Measurements', Boundary-Layer Meteorol. 35, 409-413.
Goode, K., and Belcher, S. E.: 1999, 'On the Parameterisation of the Effective Roughness Length for Momentum Transfer over Heterogeneous Terrain', Boundary-Layer Meteorol. 93, 133-154.
Hasager, C. B. and Jensen, N. O.: 1999, 'Surface-Flux Aggregation in Heterogeneous Terrain', Quart. J. Roy. Meteorol. Soc. 125, 2075-2102.
Hasager, C. B. and Thykier-Nielsen, S.: 2001, 'IRS-1C LISS III Land Cover Maps at Different Spatial Resolutions Used in Real-Time Accidental Air Pollution Deposition Modelling', Remote Sens. Environ. 76, 326-336.
Hasager, C. B., Astrup, P., Barthelmie, R. J., Dellwik, E., Jørgensen, B. H., Mortensen, N. G., Nilesen, M., Pryor, S. C., and Rathmann, O.: 2002, Validation of Satellite SAR Offshore Wind Speed Maps to In-Situ Data, Mesoscale and Micro-ScaleModel Results, Risø-R-1298, pp. 1-273, http://www.risoe.dk/rispubl/VEA/ris-r-1298.htm
Klaassen, W. and Claussen, M.: 1995, 'Landscape Variability and Surface Flux Parameterization in Climate Models', Agric. For. Meteorol. 73, 181-188.
Lettau, H.: 1969, 'Note on Aerodynamic Roughness-Parameter Estimation on the Basis of Roughness Element Description', J. Appl. Meteorol. 8, 828-832.
Mason, P.: 1988, 'The Formation of Areally-Averaged Roughness Lengths', Quart. J. Roy. Meteorol. Soc. 114, 399-420.
National Cadastre and Survey: 1995-2000, Top10DK Digital Vector Map.
Raupach, M.: 1994, 'Simplified Expressions for Vegetation Roughness Length and Zero-Plane Displacement as Functions of Canopy Height and Area Index', Boundary-Layer Meteorol. 71, 211-216.
Roeckner, E., Arpe, K., Bengtsson, L., Christoph, M., Claussen, M., Dümenil, L., Esch, M., Giorgetta, M., Schlese, U., and Schulzwida, U.: 1996, The Atmospheric General Circulation Model ECHAM-4: Model Description and Simulation of Present-Day Climate, MPI Report 218, Max-Planck-Institute, Hamburg.
Sass, B. H., Nielsen, N.W., Jørgensen, J. U., and Amstrup, B.: 1999, The Operational DMI-HIRLAM System, 2nd rev. edn., DMI Technical Report, 99-21.
Sattler, K.: 1999, New High Resolution Physiographic Data and Climate Generation for the HIRLAM Forecasting System, DMI Technical Report, 99-11. Available from http://www.dmi.dk
Schmid, H. P. and Bünzli, B.: 1995, 'The Influence of Surface Texture on the Effective Roughness Length', Quart. J. Roy. Meteorol. Soc. 121, 1-21.
Sempreviva, A. M., Larsen, S. E., Mortensen, N. G., and Troen, I.: 1990, 'Response of Neutral Boundary-Layers to Changes of Roughness', Boundary-Layer Meteorol. 50, 205-225.
Seth, A., Giorgi, F., and Dickinson, R. E.: 1994, 'Simulating Fluxes from Heterogeneous Land Surfaces-Explicit Sub-Grid Method Employing the Biosphere-Atmosphere Transfer Scheme (BATS)', J. Geophys. Res.-Atmos. 99, 18651-18667.
Soegaard, H., Jensen, N. O., Boegh, E., Hasager, C. B., Schelde, K., and Thomsen, A.: 2003, 'Carbon Dioxide Exchange over an Agricultural Landscape Analysed by Combining Eddy Correlation Measurements with Footprint Modelling', Agric. For. Meteorol. 114, 153-173.
Su, Z., Pelgrum, H., and Menenti, M.: 1999, 'Aggregation Effects of Surface Heterogeneity in Land Surface Processes', Hydrol. Earth System Sci. 3, 549-563.
Thom, A. S.: 1971, 'Momentum Absorption by Vegetation', Quart. J. Roy. Meteorol. Soc. 47, 414-428.
Walmsley, J. L., Taylor, P.A., and Keith, T.: 1986, 'A Simple-Model of Neutrally Stratified Boundary-Layer Flow over Complex Terrain with Surface-Roughness Modulations (MS3DJH/3R)', Boundary-Layer Meteorol. 36, 157-186.
Wieringa, J.: 1993, 'Representative Roughness Parameters for Homogeneous Terrain', Boundary-Layer Meteorol. 63, 323-363.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hasager, C.B., Nielsen, N.W., Jensen, N.O. et al. Effective Roughness Calculated from Satellite-Derived Land Cover Maps and Hedge-Information used in a Weather Forecasting Model. Boundary-Layer Meteorology 109, 227–254 (2003). https://doi.org/10.1023/A:1025841424078
Issue Date:
DOI: https://doi.org/10.1023/A:1025841424078