ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-7-4513-2007 Validation of Martilli's urban boundary layer scheme with measurements from two mid-latitude European cities Hamdi R. 1 Schayes G. 2 Royal Meteorological Institute, Avenue Circulaire, 3, 1180 Brussels, Belgium Institut d'Astronomie et de Géophysique, University of Louvain, Belgium 31 08 2007 7 17 4513 4526 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/7/4513/2007/acp-7-4513-2007.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/7/4513/2007/acp-7-4513-2007.pdf

Martilli's urban parameterization scheme is improved and implemented in a mesoscale model in order to take into account the typical effects of a real city on the air temperature near the ground and on the surface exchange fluxes. The mesoscale model is run on a single column using atmospheric data and radiation recorded above roof level as forcing. Here, the authors validate Martilli's urban boundary layer scheme using measurements from two mid-latitude European cities: Basel, Switzerland and Marseilles, France. For Basel, the model performance is evaluated with observations of canyon temperature, surface radiation, and energy balance fluxes obtained during the Basel urban boundary layer experiment (BUBBLE). The results show that the urban parameterization scheme represents correctly most of the behavior of the fluxes typical of the city center of Basel, including the large heat uptake by the urban fabric and the positive sensible heat flux at night. For Marseilles, the model performance is evaluated with observations of surface temperature, canyon temperature, surface radiation, and energy balance fluxes collected during the field experiments to constrain models of atmospheric pollution and transport of emissions (ESCOMPTE) and its urban boundary layer (UBL) campaign. At both urban sites, vegetation cover is less than 20%, therefore, particular attention was directed to the ability of Martilli's urban boundary layer scheme to reproduce the observations for the Marseilles city center, where the urban parameters and the synoptic forcing are totally different from Basel. Evaluation of the model with wall, road, and roof surface temperatures gave good results. The model correctly simulates the net radiation, canyon temperature, and the partitioning between the turbulent and storage heat fluxes.

 References Bornstein, R. D.: Mean diurnal circulation and Thermodynamic Evolution of Urban Boundary Layers, Modelling the Urban Boundary Layer, published by American Meteorological Society, Boston, MA, 53–94, 1987. Brown, M. and Williams, M.: An urban canopy parameterization for mesoscale meteorological models, AMS 2nd Urban Env. Symp., Albuquerque, NM, 1998. Brown, M.: Urban parameterizations for mesoscale meteorological models, Mesoscale Atmospheric dispersion, edited by: Boybey, Z., Wessex press, 2000. Ca, V., Asaeda, T., and Ashie, Y.: Development of a numerical model for the evaluation of the urban thermal environment, J. Wind. Eng. Ind. Aerodyn., 81, 181–196, 1999. Christen, A.: Atmospheric turbulence and surface energy exchange in urban environments, Ph.D. thesis, Univ. Basel, Switzerland, 130 pp, 2005. Christen, A. and Vogt, R.: Energy and radiation balance of a central European city, Int. J. Climatol., 24, 1395–1421, 2004. Eliasson, I.: Urban nocturnal temperatures, street geometry and land use, Atmos. Environ., 30, 379–392, 1996. Gao, W.: Thermal effects of open space with a green area on urban environment, Part 1: a theoretical analysis and its application, J. Archit. Plan. Environ. Eng., AIJ, No. 448, 1993. Hamdi, R.: Numerical study of the atmospheric boundary layer over urban areas: validation for the cities of Basel and Marseille, Ph.D. thesis, Univ. Louvain, Belgium, 242 pp, 2005. Lemonsu, A. and Masson, V.: Simulation of a summer urban breeze over Paris, Bound. Lay. Meteorol., 104, 463–490, 2002. Lemonsu, A., Grimmond, C. S. B., and Masson, V.: Modelling the surface energy balance of the core of an old Mediterranean city: Marseilles, J. Appl. Meteorol., 43, 312–327, 2004. Martilli, A., Clappier, A., and Rotach, M. W.: An urban surface exchange parameterization for mesoscale models, Bound. Lay. Meteorol., 104, 261–304, 2002. Maruyama, T.: Surface and inlet boundary conditions for the simulation of turbulent boundary layer over complex rough surface, J. Wind. Eng. Ind. Aerodyn., 81, 311–322, 1999. Masson, V.: A physically-based scheme for the urban energy budget in atmospheric models, Bound. Lay. Meteorol., 94, 357–397, 2000. Mestayer, P. G., Durand, P., Augustin, P., et al.: The urban boundary layer field experiment over Marseille. UBL/CLU-ESCOMPTE: Experimental set-up and first results, Bound. Lay. Meteorol., 114, 315–365, 2005. Pigeon, G., Lemonsu, A., Durant, P., and Masson, V.: Urban surface network in Marseille: Network optimization using numerical simulations and results, Preprints, Fourth Symp. on the Urban Environment, Norfolk, VA, Am. Meteorol. Soc., 23–24, 2002. Rotach, M. W.: Turbulence close to a rough urban surface. Part1: Reynold Stress, Bound. Lay. Meteorol., 65, 1–28, 1993. Rotach, M. W.: Turbulence close to a rough urban surface. Part 2: Variances and gradients, Bound. Lay. Meteorol., 65, 1–28, 1993. Rotach, M. W., Vogt, R., Bernhofer, C., Batchavarova, E., Christen, A., Feddersen, B., Gryning, S.-E., Martucci, G., Mayer, H., Mitev, V., Oke, T. R., Parlow, E., Richner, H., Roth, M., Roulet, Y. A., Ruffieux, D., Salmond, J., Schatzmann, M., and Voogt, J.: BUBBLE: a Major Effort in Urban Boundary Layer Meteorology, Theor. Appl. Climatol., 81, 231–261, 2005. Roulet, Y.-A., Martilli, A., Rotach, M. W., and Clappier, A.: Validation of an urban surface exchange parameterization for mesoscale models – 1D case in a street canyon, J. Appl. Meteorol., 44, 1484–1498, 2005. Schayes, G., Thunis, P., and Bornstein, R.: Topographic Vorticity-Mode Mesoscale-$\beta $ (TVM) Model. Part1: Formulation, J. Appl. Meteorol., 35, 1815–1824, 1996. Sievers, U.: Dreidimensionale simulation in stadtgebieten, Schriftenreihe Umweltmeteorologie Band 15 (in German), Kommission Reinhaltung der Luft im VDI und DIN, Dusseldorf, 36–43, 1990. Taha, H.: Modeling the impacts of large-scale albedo changes on ozone air quality in the south coast air basin, Atmos. Environ., 31, 1667–1676, 1997. Taha, H.: Modifying a mesoscale meteorological model to better incorporate urban heat storage: bulk-parameterization approach, J. Appl. Meteorol., 38, 466–473, 1999. Tatsou Oka: Thermal environment in urban areas, Report D7: 1980, Swedish Council for Building Research, Stockholm, Sweden, 1980. Therry, G. and Lacarrère, P.: Improving the eddy kinetic energy model for planetary boundary layer description, Bound. Lay. Meteorol., 25, 63–88, 1983. Thunis, P. and Clappier, A.: Formulation and Evaluation of a Nonhydrostatic Mesoscale Vorticity Model (TVM), Mon. Weather Rev., 128, 3236–3251, 2000. Urano, A., Ichinose, T., and Hanaki, K.: Thermal environment simulation for 3-D replacement of urban activity, J. Wind Eng. Ind. Aerodyn., 81, 197–210, 1999.