Search results for "Urban climatology"
showing 3 items of 3 documents
Temperature Inversion Breakup with Impacts on Air Quality in Urban Valleys Influenced by Topographic Shading
2015
AbstractUrban valleys can experience serious air pollution problems as a combined result of their limited ventilation and the high emission of pollutants from the urban areas. Idealized simulations were analyzed to elucidate the breakup of an inversion layer in urban valleys subject to a strong low-level temperature inversion and topographic effects on surface heating such as topographic shading, as well as the associated air pollution transport mechanisms. The results indicate that the presence and evolution in time of the inversion layer and its interplay with an urban heat island within the valley strongly influence the venting of pollutants out of urban valleys. Three mechanisms of air …
Effects of Urbanization on the Temperature Inversion Breakup in a Mountain Valley with Implications for Air Quality
2014
AbstractMany cities located in valleys with limited ventilation experience serious air pollution problems. The ventilation of an urban valley can be limited not only by orographic barriers, but also by urban heat island–induced circulations and/or the capping effect of temperature inversions. Furthermore, land-use/-cover changes caused by urbanization alter the dynamics of temperature inversions and urban heat islands, thereby affecting air quality in an urban valley. By means of idealized numerical simulations, it is shown that in a mountain valley subject to temperature inversions urbanization can have an important influence on air quality through effects on the inversion breakup. Dependi…
Surface to boundary layer coupling in the urban area of Lisbon comparing different urban canopy models in WRF
2019
Abstract This work presents a sensitivity study to evaluate different Urban Canopy Models (UCM) existing within the Weather Research and Forecasting Model (WRF) in the urban area of Lisbon, Portugal. Several hind-cast simulations were carried out for a selected period in July 2010, in which synoptic conditions favoured urban heat island formation. We aim to gain knowledge on the feedback of modified urban canopy representation in WRF on local scale meteorology and the boundary-layer dynamics over the urban area, by comparing a single layer urban canopy model (SLUCM) and a more sophisticated multi-layer building effect parametrisation (BEP). We find significant differences in the characteris…