Impact Of Urban Climate Research Articles

Comparative assessment of night ventilation performance in a nearly zero-energy office building during heat waves in Brussels

With increasing urbanization, overheating intensifies, resulting in a greater risk of indoor overheating in commercial buildings, which already have high internal gains. The impact of urban climate on the cooling energy needs of buildings has been extensively researched. However, the building performance during extreme heat events needs further investigation to reduce the energy demand from the grid during critical events and to ensure an acceptable indoor thermal environment. Here, a comparative assessment approach for natural and mechanical night ventilation performance to reduce indoor overheating and energy needs of a nearly zero-energy office building in Brussels, Belgium, was evaluated for the heat wave and non-heat wave periods in urban and rural microclimates, using calibrated thermal-energy simulations. The analysis indicated that active cooling with natural night ventilation was more effective during heat waves than other cooling strategies. In addition, natural night ventilation was also effective in maintaining safer levels of heat index values in the reference office compared to other strategies. Natural night ventilation reduced overheating by 0.39 °C in the urban microclimate and 0.50 °C in the rural microclimate relative to the Baseline. Considering the cooling energy use, natural night ventilation had no significant impact. In contrast, mechanical night ventilation increased energy use by 0.54 kWh/m2 in urban microclimate and 0.40 kWh/m2 in rural microclimate due to prolonged ventilation fan operation in the reference office building. The presented findings in the paper lead to the formulation of design guidelines, recommendations for future practices and identifying needs for further research.

Assessing urban climate effects on Pinus sylvestris with point dendrometers: a case study from Stockholm, Sweden

Key messageExtreme drought conditions, in addition to the urban heat island effect, modify the growth response and water storage dynamics of urban Scots pine trees in the Stockholm region.Changes in surface properties of the urban environments significantly impact the local microclimate. While urban trees are known for providing important thermal regulation, the impact of urban climate on tree growth remains relatively unexplored. The present study focuses on the climate response and growth dynamics of urban Scots pine trees (P. sylvestris) in comparison to their rural counterparts. High-resolution monitoring of stem-radius variations using automatic point dendrometers was performed during the growing seasons (April–October) of 2017 and 2018 in Stockholm, Sweden. In 2018, the region experienced a severe and long-lasting summer drought. In May and July, temperatures were up to 5 °C higher relative to the reference period (1981–2010), and precipitation sums were below the reference period for the entire growing season. Our results show that the urban climate primarily impacts the daily water storage dynamics by decreasing the radius change amplitudes and delaying the time of maximum stem-water replenishment and depletion. Under standard climatic conditions, the warmer climate (1.3 °C) at the urban sites had a positive impact on radial growth increment. Drought periods significantly impact the climate–growth relationships. Stem shrinkage intensifies during the day, and lower growth rates were registered, resulting in reduced annual growth. The high-resolution monitoring provided valuable insights into daily and seasonal patterns of Scots pine stem-radius variations, showing that growth responses to increasing temperature are mainly controlled by moisture availability and site-specific conditions.

Long-term air temperature changes in Ljubljana (Slovenia) in comparison to Trieste (Italy) and Zagreb (Croatia)

Abstract The cities of Ljubljana, Trieste and Zagreb are proximate in terms of distance but differ in terms of geographical and climatic conditions. Continuous meteorological measurements in these cities began in the mid-19th century. The 100-year trends of changes in mean annual and seasonal air temperatures for these cities are presented here, evaluating the differences between them which result from their different geographical and climatic positions. Differences in trends between Ljubljana and Zagreb that result from different measurement histories and the impact of urban climate are also presented: the impact of city growth on air temperatures in Ljubljana after 1950 was not completely eliminated in the process of data homogenization. The lowest air warming trends occur in the maritime climate of Trieste (mean annual air temperature: + 0.8 °C × 100 yr−1), where measurements were continuously performed in the densely built-up section of the city. The strongest trends occur in Ljubljana, mainly due to city growth (mean annual air temperature: + 1.1 °C × 100 yr−1). Comparing the linear trends in Zagreb-Grič and in Ljubljana, the impact of Ljubljana's urban heat island on the 100-year warming trend was assessed at about 0.2 °C, at 0.3–0.4 °C for the trend after 1950, and if non-homogenized data are used, at about 0.5 °C.

공간유형 및 사용방안에 따른 도시기후의 변화 및 영향에 관한 정량적 연구 - 생태면적률을 적용하여 -

Urbanization and Population concentration are made city, that is solid and smooth, unchanging characteristics. These materials are shown to increase the impermeability. The impermeability exacerbate function of circulation and as a result various problems arise. It is presented as a solution to the Biotops Area Ratio Calculation. The Biotops Area Ratio Calculation is Space Type Elements is applied to decide the purpose of recovering the function of the city. In this study, according to the Biotops Area Ratio Calculation impact of urban space is to analyze quantitatively. The purpose of this study is the analysis of the Changes and Effects in the Urban Climate by the Biotop Area Ratio Calculation in terms of Redevelopment and Partial Improvement. Fundamental research methods for this research to proceed. To analyze the effects of the urban climate shown using Envi-met simulated. For improvements to the city's function of water circulation to identify the area and simply applying the space type elements. Analysis of, on the basis of simulation, temperature, humidity and other conditions. Used for behavior determines the impact of urban climate. The analysis results, the weight is shown in climate change and maintain proportionality. And, using the optimal conditions are selected according to the behavior is important. So, in order to use the space for an active form of the type used for quantitative studies are required.

Biometeorological studies on urban climate.

Urban-biometeorology, i.e., biometeorological study on the urban climate is regarded as both old and/or new science. Studies on two topics are reviewed: the thermal or chemical impact of urban climate on human health, and the relation between urban climate and vegetation.