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)

2016

Popis analýzy informačního obsahu dat, které bylo možno vzdáleně vyčíst z vozidlových jednotek při zkušebním provozu v rámci projektu TA04020797.

Výzkumná zpráva v češtině

2016, HARMO 2016 - 17th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings, Budapest, Hungarian Meteorological Service), p. 117-120), ISBN 9789639931107

High-quality emission data are of utmost importance for the reliable outputs of air quality models. AQ models require speciated hourly emissions, whereas emission inventories are constructed on annual basis and include only main pollutants. For the time disaggregation simple and constant monthly, daily, and hourly factors are usually used. Likewise, chemical speciations are usually based on outputs of very few and sometimes quite old reports and do not necessarily correspond to the situation in the country of interest. For the emission processing itself many scientific groups use SMOKE pre-processor, due its availability and since it is fitted for the WRF and CMAQ models. Nevertheless, its application for non-US countries can be quite complicated due to different data and metadata structure. Our project focusses on two aims: 1) The derivation of the time and speciation profiles specific for the Czech Republic. For this purpose, we analyse continuous emission measurements from the large stationary sources, temperature and behaviour dependency of the household heating emission, and the data available in the extensive Czech emission database REZZO. For the transport we managed to access data from the Electronic Control Units (ECU) of the vehicular fleet maintained by the SHERLOG company. These unique data give us information on engine state, fuel consumption, and driving styles from the real traffic flow. 2) The construction of a flexible emission processor for AQ models based on the freely available software.

Stať ve sborníku z prestižní konf. (Scopus)

2016

Zpráva popisuje architekturu a jednotlivé součásti navrhovaného emisního modelu. Dále obsahuje popis propojení jednotlivých submodulů a toky a formáty dat.

Výzkumná zpráva v češtině

2016, HARMO 2016 - 17th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings, Budapest, Hungarian Meteorological Service), p. 362-366), ISBN 9789639931107

Cities play an important role regarding potential climate change impacts. Urban areas are often vulnerable and poorly prepared to respond to climate change impacts, such as heat waves. Within UrbanAdapt project we aim to perform high-resolution street-level modelling to evaluate different adaptation measures which are orientated to lower the temperature in the streets during hot summer days. The heterogeneity of urbanized land surface leads to a need for a very fine resolution when modelling air flows and temperature near to the surface. We have chosen the atmospheric model PALM as a tool for our simulations. PALM is a LES model which includes parametrizations of many atmospheric processes (e.g. land surface, plant canopy, solar radiation and convective processes) and also enables to involve pollutant dispersion. On the other hand, the parametrization of building surface energy balance is not included in the model. To account for the realistic implementation of urban canopy processes in complex urban geometry we enhanced PALM model including some of the most important urban canopy mechanisms. In order to evaluate the new module, we performed a field experiment, during which temperature of building facades and road surface on Prague crossroad were measured with infrared camera, during a summer heat wave episode. Newly developed module will be used to estimate the effects of different adaptation measures (planting tree alleys, changing wall paint colors), on air quality and thermal comfort of city inhabitants.

Stať ve sborníku z prestižní konf. (Scopus)

2015, 2015 Smart Cities Symposium Prague (SCSP), New York, IEEE Press), ISBN 978-1-4673-6727-1

Selected aspects of project UrbanAdapt are described. The project deals with the adaptation of cities on changing climatic conditions. The main project objective is to start the process of preparation of cities adaptation strategies, developing adaptation scenarios and testing the effects and benefits of particular measures. Project team involves groups from different fields that cover various aspects of adaptation measures including economic analyses, policy making processes, education and dissemination to the public. The presented paper deals with the part of activities which are focused on modelling of adaptation measures and climatic impacts for the city of Prague. These activities include assessment of energy balance of city, in terms of interactions of solar radiation, atmosphere and urban environment. Urban environment includes not only buildings, street surfaces and vegetation, but also the processes having impact on energy balance such as the traffic, air conditioning and industry that produce anthropogenic heat which can play a role for example in summer heat waves. The ultimate goal is to assess the impact of different adaptation measures on citizens who live in environmental conditions of growing effect of urban heat island. Thus the connection between objective meteorological variables and subjective biological indices has to be investigated. The concept of Physiological Equivalent Temperature (PET) is adopted. In comparison to single values of air temperature, air humidity, global horizontal irradiance, wind speed, and other meteorological indexes, concept of PET has added value in determining the value of important biometeorological index in easily recognizable quantity such as °C. Micro-scale models can be one way to study proposed adaptation measures such as tree alleys, bodies of water, etc.

Stať ve sborníku z prestižní konf.

2015, Smart Cities Symposium Prague 2015 Proceedings - Czech Technical University in Prague, Praha, České vysoké učení technické v Praze, Fakulta dopravní), p. 26-26), ISBN 978-80-01-05742-1

Selected aspects of project UrbanAdapt are described. The project deals with the adaptation of cities on changing climatic conditions. The main project objective is to start the process of preparation of cities adaptation strategies, developing adaptation scenarios and testing the effects and benefits of particular measures. Project team involves groups from different fields that cover various aspects of adaptation measures including economic analyses, policy making processes, education and dissemination to the public. The presented paper deals with the part of activities which are focused on modelling of adaptation measures and climatic impacts for the city of Prague. These activities include assessment of energy balance of city, in terms of interactions of solar radiation, atmosphere and urban environment. Urban environment includes not only buildings, street surfaces and vegetation, but also the processes having impact on energy balance such as the traffic, air conditioning and industry that produce anthropogenic heat which can play a role for example in summer heat waves. The ultimate goal is to assess the impact of different adaptation measures on citizens who live in environmental conditions of growing effect of urban heat island. Thus the connection between objective meteorological variables and subjective biological indices has to be investigated. The concept of Physiological Equivalent Temperature (PET) is adopted. In comparison to single values of air temperature, air humidity, global horizontal irradiance, wind speed, and other meteorological indexes, concept of PET has added value in determining the value of important biometeorological index in easily recognizable quantity such as °C. Micro-scale models can be one way to study proposed adaptation measures such as tree alleys, bodies of water, etc.

Abstrakt ve sborníku z mezinár. konf. cizojazyčně

2013

Modelování imisních scénářů pro území hl.m. Prahy a nejbližšího okolí pro zadané scénáře pro roky 2010, 2020 a 2030

Výzkumná zpráva v češtině