Lidé na fakultě
RNDr. Kryštof Eben, CSc.

2017, Geoscientific Model Development, 10 (10), p. 3635-3659), ISSN 1991-959X

Urban areas are an important part of the climate system and many aspects of urban climate have a direct effect on human health and living conditions. This implies the need for a reliable tool for climatology studies that supports urban planning and development strategies. However, a realistic implementation of urban canopy processes still poses a serious challenge for weather and climate modelling for the current generation of numerical models. To address this demand, a new model of energy processes for urban environments was 5 developed as an Urban Surface Model (USM) and integrated as a module into the large-eddy simulation (LES) model PALM. The USM contains a multi-reflection radiation model for short and long wave radiation, calculation of the energy balance on horizontal and vertical impervious surfaces, thermal diffusion in ground, wall and roof materials and anthropogenic heat from transportation. The module also models absorption of radiation by resolved plant canopy (i.e. trees, shrubs). The USM was parallelized using MPI and performance testing demonstrates that the computational costs 10 of the USM are reasonable and the model scales well on typical cluster configurations. The module was fully integrated into PALM and is available via its online repository under GNU General Public License (GPL). The implementation was tested on a summer heat wave episode in the real conditions of a selected Prague crossroad. General patterns of temperature of various surface types (walls, pavement) are in good agreement with observations. The coupled LES-USM system appears to correct the bias found between observations and mesoscale model predictions for the near-surface air temperature. The results, however, 15 show a strong dependence on the prescribed surface and wall material properties. Their exact knowledge is thus essential for the correct prediction of the flow in the urban canopy layer.

Článek v periodiku excerpovaném SCI Expanded

2017, HARMO 2017 - 18th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings, Budapest, Hungarian Meteorological Service), p. 611-616)

Urban mitigation scenarios for the development area in Prague, Czech Republic were calculated by the LES model PALM extended with the urban surface model for radiation processes. Scenarios included the effect of tree planting and surface albedo adjustment on the surface temperature and NOX concentrations during a summer heat wave episode. It was shown that positive effect (cooling) in temperature can be accompanied by the increase of NOX concentration. Thus the impact of urban mitigation scenarios has to be carefully assessed from all relevant points of view.

Stať ve sborníku z prestižní konf. (Scopus)