The heat balance of a residential suburb of Miami, Florida

The heat balance of cities in tropical climates, where urban development is greatest, are almost absent. Pilot work has been conducted in tropical highland (Mexico City) and desert (Tucson) cities, but none in hot, wet climates. This was the rationale for a field study in a neighborhood of Miami, FLA in May-June 1995. The area consists of 1-2 storey single-family houses with considerable greenspace and freely available water in the form of open ditches and canals. All component fluxes of the radiation budget were monitored directly. The diurnal course of the budget components is remarkably similar to that of standard rural sites. The derived surface albedo, is consistent with those from other urban sites. The results were used to test several formulae and parameterizations of the solar, infrared and net fluxes, with good results. The turbulent fluxes of sensible and latent heat were measured by eddy correlation at times when there was several kilometers of fetch over the neighborhood. Neglecting advection, and assuming balance closure, heat storage was found by residual. During the daytime storage consumed about 30% of the net radiation. Storage estimates compared well with those from a simple parameterization scheme. The mean daytime Bowen ratio (1.55), was larger than anticipated given the high surface water availability. This may be related to the suppression of evaporation by the small vapour deficit. Several approaches to calculation and parameterization of the turbulent fluxes were tried. A simplified Penman-Monteith approach seems to have merit.