Evaluation of the urban tile in moses using surface energy balance observations

• Published in: Boundary-layer meteorology Vol. 118; no. 3; pp. 503 - 525
• Main Authors: BEST, M. J, GRIMMOND, C. S. B, VILLANI, Maria Gabriella
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01-03-2006; Springer Nature B.V
• Subjects: Earth, ocean, space; Energy balance; Exact sciences and technology; External geophysics; Heat transfer; Latent heat; Meteorology; Net radiation; Studies; Urban areas; Vegetation cover; Weather analysis and prediction; Weather forecasting; Canada; Mexico; British Columbia; Western Canada; British Isles; Mexico, Distrito Federal, Mexico City; Canada, British Columbia, Vancouver; Weather forecast; Sensitivity analysis; Megalopolis; Urban energy balance; energy balance; case studies; urban areas; Forecast model; Parameterization; North America; Micrometeorology; algorithm performance; Ground surface; Surface scheme; Model evaluation; Numerical forecast; Surface energy; Canopy(vegetation)
• ISSN: 0006-8314; 1573-1472
• DOI: 10.1007/s10546-005-9025-5

The UK Met Office has introduced a new scheme for its urban tile in MOSES 2.2 (Met Office Surface Exchange Scheme version 2.2), which is currently implemented within the operational Met Office weather forecasting model. Here, the performance of the urban tile is evaluated in two urban areas: the historic core of downtown Mexico City and a light industrial site in Vancouver, Canada. The sites differ in terms of building structures and mean building heights. In both cases vegetation cover is less than 5%. The evaluation is based on surface energy balance flux measurements conducted at approximately the blending height, which is the location where the surface scheme passes flux data into the atmospheric model. At both sites, MOSES 2.2 correctly simulates the net radiation, but there are discrepancies in the partitioning of turbulent and storage heat fluxes between predicted and observed values. Of the turbulent fluxes, latent heat fluxes were underpredicted by about one order of magnitude. Multiple model runs revealed MOSES 2.2 to be sensitive to changes in the canopy heat storage and in the ratio between the aerodynamic roughness length and that for heat transfer (temperature). Model performance was optimum with heat capacity values smaller than those generally considered for these sites. The results suggest that the current scheme is probably too simple, and that improvements may be obtained by increasing the complexity of the model.[PUBLICATION ABSTRACT]