Impact of Land Use and Land Cover Changes on Surface Energy Balance of a Tropical Mountain City: A Study Case in Medellín (Colombia)

Abstract:

The land use and cover changes (LUCC) modify physical land surface properties and consequently force variations in energy flows and atmospheric dynamics. In Medellin, a tropical city in a mountain valley, urbanization processes have shifted the border of vegetation, turning vegetated areas into non-natural ones. In this study, we used the Weather Research and Forecasting model (WRF) to simulate the effects of urbanization on the surface energy balance in Medellín. Sensible and latent heat fluxes were estimated for several scenarios including the actual one and some others with different urban green area configuration. Subsequently we made a comparative analysis of magnitudes and spatial pattern of changes in storage and fluxes of energy fluxes between the scenarios. Results suggest that the spatial distribution of vegetation within the city regulates the dynamics of surface energy balance due mainly to vegetation transpiration and surface albedo changes. At the same time, there is a cooling effect of green areas on surrounding urban areas. The increase of vegetation within the cities could attenuate the urban heat island (UHI) effect. Research conclusions can offer useful information for the land use planning and climate change adaptation in Medellin and near cities, taking into account the regulatory role of vegetation in urban meteorology.