Different development of global warming (GW) and urban heat island (UHI) in the city of Zagreb (original) (raw)

The extent and implications of the urban heat island phenomenon in Central European region

Metropolitan areas worldwide display highly diverse microclimatic circumstances that are influenced by a variety of morphologies, structures, materials (particularly urban surface properties), and processes (mobility, industry, etc.). This diversity influences the intensity and extent of the urban heat island effect (UHI) in different cities. UHI may be understood in terms of emerging divergence between micro-climatic conditions in the city proper versus the rural environs. Significantly higher temperatures are observed in the urban area as compared to the surrounding suburban and rural neighborhoods. A further rise in the appearance and intensity of UHI phenomena is to be expected in the coming years due to the on-going population increase in urban areas. Furthermore, the UHI effect is believed to be related to (and worsened by) the climate change. Thereby, the rise of global temperatures is likely to affect not only the health of the urban population (urban heat distress, pedestrian discomfort) but also the energy performance of the built environment (higher outdoor air temperatures lead to a significant increase in buildings' energy use for cooling). In this context, this paper presents the results of an on-going EU-supported research project, which investigates the urban heat island phenomena in a number of urban regions in Central European countries (Stuttgart, Warsaw, Prague, Padua, Ljubljana, Modena, and Budapest). Toward this end, we pursue a two-fold approach. First detailed information regarding urban and rural climate in a 7-day period for each of the participating cities was collected and analysed. The results show a considerable variance, which, if ignored, would lead to major uncertainties in inferences made based on performance simulation. Secondly, long term data on rural and urban climate was obtained for all participating cities and included in the analyses.

Impact of climate change on urban heat island effect and extreme temperatures: a case‐study

This study investigated the impacts of climate change on the urban heat island (UHI) and the number of very hot (maximum temperature >35°C) and very cold days (minimum temperature <5°C) in the central business district (CBD) of Melbourne city in Australia. A station located in Laverton (less urbanised area), which is 17 km southwest of Melbourne CBD, was selected as the reference station for the computation of UHI intensity in Melbourne CBD. Using daily minimum/maximum temperatures at the two stations, nocturnal/diurnal UHI intensities in Melbourne CBD were computed for the period 1952–2010. It was found that in Melbourne CBD, nocturnal UHI intensities show a clear rising trend over the period 1952–2010 unlike the diurnal UHI intensities. For the analysis of nocturnal UHI intensities in Melbourne CBD, under changing climate, for each calendar month statistical models based on the gene expression programming (GEP) technique were developed for downscaling general‐circulation model (GCM) outputs to monthly average minimum temperature at Melbourne CBD and Laverton. Using the outputs of HadCM3, GFDL2.0 and ECHAM5 pertaining to the A2 greenhouse gas emission scenario on the downscaling models, projections of monthly average minimum temperature were produced for the two stations over the period 2000–2099. In each season, at both stations, the ensemble average of monthly minimum temperature gradually increased over the period 2000–2099. The ensemble‐average UHI intensity in Melbourne CBD projected into the future was higher for all seasons in comparison to that of period 1952–1971. Downscaling models based on the GEP technique were developed for each calendar month for projecting the number of very hot days in November–March and very cold days in May–September in Melbourne CBD. It was found that, in the future, summer weather will spread to early autumn, and winter weather will move to early spring, in Melbourne CBD.

Assessing temperature warming and cooling rates using simple statistical analysis: The case study of Jalingo metropolis

Journal of the Bulgarian Geographical Society

Urban climatologist particularly those interested in Urban Heat Island (UHI), require some form of explanations to UHI variations at both spatial and temporal scales in cities. Temperature cooling and warming rate can be use as a form of explanations for spatial and temporal variations for UHI intensity characteristics of an area. This study therefore, assessed variations in temperature warming and cooling rates in Jalingo. The study used temperature data collected at six locations representing six different thermal climate zones in the study area. Temperature data were collected for the period of 90 days thirty days in each of rainy season, dry season, and hamattan period. Simple statistical analysis was performed to determine the warming and cooling rates. The results indicate that temperature warm and cool differently in the study area. The results also revealed that general warming in the area within the study period begins at 8:00 h local time (GMT +1) with warming rate ranging...

Analysis of micro climatic variations and the urban heat island phenomenon in the city of Vienna

"Metropolitan areas are dealing with very diverse microclimatic situations influenced by different morphologies, structures, and materials of the built environment. Moreover, it has been proven that urban areas show significantly higher temperatures than rural surroundings. This is referred to as the urban heat island phenomenon (UHI). Furthermore, the UHI effect is directly related to (and worsened by) the climate change phenomena, where it is expected that an increase of the average temperature has a stronger and immediate effect on the health of people living in cities. Additionally higher air temperatures have a direct effect on the energy consumption due to increased use of air conditioning. In this context this paper presents results of an ongoing research project which investigates the urban heat island phenomena in the Central European area. Specifically, this paper analyzes the urban heat island phenomenon and microclimate conditions looking at various locations in the city of Vienna. Towards this end, existing weather stations in urban as well as rural locations have been selected and the data has been analyzed and compared with regard to the surrounding area in terms of density, surface characteristics, and vegetation. Specifically, the urban heat island intensity, the diurnal variation, and the seasonal trend of temperature differences were investigated. Based on the analysis, the main contributing factors and typical characteristic patterns will be discussed."

Distinguishing between Global Warming and Urban Warming for Bangalore with the aid of Statistical Analysis

2014

The present research presents a statistical framework for distinguishing between Urban Warming and Global Warming, as an outcome of urbanisation. While global warming is the increase in the average temperature of earth's near-surface air, Urban Warming in the form of Urban Heat Islands (U.H.I.), signifies an urban area warmer than its rural surroundings brought about by man-made alterations of the urban surface. This research presents a local climatological investigation so as to distinguish between both forms of warming for Bangalore. To achieve this, ambient air temperature was monitored and recorded simultaneously at 12 stationary observatories in adherence to meteorological guidelines. Industrial belt across Bangalore West had mercury touching 30°C, while residential layouts near water-bodies on the same day and time were found to be coolest with maximum temperature not exceeding 24°C. Rural fringes of Bangalore North owing to relatively undisturbed natural terrain had a min...

The Impact of Climate Change on Urban Thermal Environment Dynamics

Atmosphere, 2021

The human population is increasing. The ongoing urbanization process, in conjunction with climate change, is causing larger environmental footprints. Consequently, quality of life in urban systems worldwide is under immense pressure. Here, the seasonal characteristics of Maribor’s urban thermal environment were studied from the perspectives of surface urban heat island (SUHI) and urban heat island (UHI) A remote sensing thermal imagery time series and in-situ measurements (stationary and mobile) were combined with select geospatial predictor variables to model this atmospheric phenomenon in its most intensive season (summer). Finally, CMIP6 climate change scenarios and models were considered, to predict future UHI intensity. Results indicate that Maribor’s UHI intensity maximum shifted from winter to spring and summer. The implemented generalized additive model (GAM) underestimates UHI intensity in some built-up parts of the study area and overestimates UHI intensity in green vegeta...