Modelled Spatiotemporal Variability of Air Temperature during a Heat Wave Under Real and Modified Landcover Characteristics: The Case of Brno and Prague (Czech Republic)

0494892 - ÚI 2019 US eng A - Abstrakt
Geletič, Jan - Lehnert, M. - Jurek, M.
Modelled Spatiotemporal Variability of Air Temperature during a Heat Wave Under Real and Modified Landcover Characteristics: The Case of Brno and Prague (Czech Republic).
ICUC 2018. Abstracts. New York: American Meteorological Society, 2018.
[ICUC 2018: International Conference on Urban Climate /10./ and Symposium on the Urban Environment /14./. 06.08.2018-10.08.2018, New York]
Institucionální podpora: RVO:67985807
Klíčová slova: MUKLIMO_3 * air temperature * albedo * urban climate * heat-wave
Obor OECD: Meteorology and atmospheric sciences
https://ams.confex.com/ams/ICUC10/meetingapp.cgi/Paper/341325

Recent studies show that more frequent and severe heat waves rank among the most serious impacts of urban climate change in Central Europe. At the same time, increasing awareness of the importance of cities in climate change adaptation leads to a higher demand for urban climate modelling. On that account, we used a non-hydrostatic “micro-scale” model based on the Reynolds-averaged Navier-Stokes equations, MUKLIMO_3 (developed by Deutscher Wetterdienst). The program was used for a simulation of spatiotemporal pattern of air temperature in the Central European cities of Brno and Prague (Czech Republic) during a heat wave event in August 2017. The particular aim of this study underscores our intention to provide results of a validated urban climate model that will be intelligible to a wider community of those who shape the environment in cities of Brno and Prague, thus: i) to simulate and validate the spatiotemporal pattern of air temperature during a heat wave that occurred in August 2017; ii) to analyze the spatiotemporal pattern of air temperature in various urban neighborhoods and iii) to simulate theoretical landcover modifications (green roofs, urban greenery, etc.) or complete changes in built-up structure (building density, building height, green spaces, tree cover density etc.) and their impact on spatiotemporal pattern of air temperature during the heat wave event. Model validation based on extensive in-situ air temperature measurement suggests that although the model results showed some uncertainties and customization, the model is capable to simulate spatio-temporal distribution of temperature on the local scale during a heat wave. Simulation results showed that 4–5 hours after sunrise an intense (“hot spot”) urban heat island began to form linked to sites with a relatively higher proportion of impermeable surfaces and large low-rise development lacking trees. In the midday hours and early afternoon, the characteristic pattern of a daytime urban heat island had already formed and included most of the compact city. Relatively cooler localities in the city center were bordered especially by urban greenery with higher trees. Immediately after sunset a typical night-time urban heat island pattern with relatively higher temperatures in compact mid-rise areas in the city center began to form. In ideal conditions, the higher temperatures in the city center persist until sunrise. A basic general assessment therefore suggests that during the heat stress events localities in densely built-up areas in the city center or areas with large low-rise development are exposed to additional increase in air temperature. Nonetheless, the temperature field (especially in night time) may be altered by local circulation systems. Our simulation results show that only substantial modifications of land cover (an increased proportion of high vegetation) or changes in built-up structure may significantly alter the spatiotemporal pattern of temperature field in urban environment during a heat stress event.
Trvalý link: http://hdl.handle.net/11104/0287939