Slab (one-tile) surface energy balance scheme: model description and preliminary validation for an urban site and a wetland site

Abstrakt

Adequate modelling of the heat balance of different surface types is key to improving high-resolution numerical weather forecasts. The problem is particularly relevant in urbanised areas, which, due to their significant accumulation of infrastructure and high population density, are particularly vulnerable to the effects of climate change. The paper presents an exhaustive description of the surface energy balance model developed by the Department of Meteorology and Climatology at the University of Lodz over the past two decades. The model uses a simple slab approach, wherein the canopy layer is regarded as a flat surface (a tile) with specific “bulk” physical parameters (radiative, aerodynamic, thermodynamic and hydrological). It was initially developed for use in urban areas, but since it is based on rather general parametrisations of surface–atmosphere fluxes, it can be applied to any land cover with specific “surface slab” parameters. Here we compare the model outputs with the measured flux data from two very distinct ecosystems: an urban setting and a wetland. Despite its simplicity, the model generally represents well the features of the heat balance of both wetlands and urban areas. The la-  tent heat flux is best represented and the sensible heat flux and the radiation balance somewhat less well, probably due to the assumption that all energy exchange occurs on an infinitesimal flat active surface.