SEARCH RESULT

Urban climates differ distinctly from those of rural areas. In urban environments, climate change is predicted to possess a remarkable impact on levels of thermal comfort in open spaces and buildings themselves. Since outdoor areas are mostly used during daytime, the evaluation of the daytime outdoor thermal comfort is of great importance. Solar radiation that affects air and surface temperature constitute a significant proportion of daytime microclimate. This is the case not only in traditionally hot countries but also in regions of mid- and northern latitudes that presently have a moderate climate. Within these, urban environments will encounter the following problems in particular; limited air ventilation structures; the probability of increasing the thermal stress, due to the entrapment of radiation via reflection; local heat fluxes and higher heat storage capacity will increase through block layout and volume of buildings. In order to deal with urban future climate conditions, urban planners, architects, landscape architects and property developers need reliable information regarding changing microclimate condition create the suitable design component relating to building style, block layout, shading facilities, urban green and street trees; therefore, the designed environment will be appropriately adapted to future climate change (Loibl et al. 2010). Nowadays, bioclimatic planning and design are well-known concepts in the field of architecture and urban planning which have been deeply researched in the last half century. In the case of landscape architecture, this new bioclimatic concept has been revealed in the 1980s (Robinette, 1983), but has been theorised, developed and applied mostly in the last two decades (Brown and Gillespie, 1995; Attia and Duchhard, 2011). The main objective of bioclimatic landscape design is to ensure a more comfortable and safer microclimate for the human habitats, especially the urban areas. Thus, the green spaces should be planned to mitigate bioclimatic challenges such as urban heat island, wind and dust storms, air pollution, etc. (Boc, 2016). The urban heat island (UHI) effect is a fact whereby a metropolis which built environment is usually significantly warmer when compare to its rural surroundings due to hard urban surfaces (Wang and Akbari 2016; Russo et al., 2016). This occurs because (1) urban surfaces are typically darker than those of surrounding areas, (2) there is less vegetation in urban areas, and (3) buildings and street surface materials with high heat capacities, store heat during the day and release heat slowly at night (Rao, 2012; Wang and Akbari 2016). To mitigate UHI effect, the urban form will be carefully design and the use of green infrastructure will be improved. Today many studies demonstrated the benefit of vegetation, urban street trees and urban green space. (Fahmy et. al., 2011; Russo et al., 2016) As a result, greenery is typically accorded a low priority in highly developed urban areas. With limited land available for urban greenery, it is necessary to understand the thermal behavior of roadside trees in built environments, plan tree planting using appropriate methods, and identify suitable planting locations on local climate (Tan et al., 2017). These determination the selected case studies are focused on, the evaluation of microclimatic effect of roadside tree planting from the perspective of pedestrian comfort enhancement was investigated in the context of high-density cities in hot and humid climates. Within the research different scenarios for the same area from the identical climatic season are analysed through a comparative study. 24 hours simulation scenarios were run with the first scenario simulating the existing situation and the second scenario simulated the domain of different vegetation species (evergreen and deciduous species) and vegetation density (low, medium and high-density plantation). All the analysed projects are concerned with improving the microclimatic condition of urban street for pedestrian thermal comfort via landscape elements, particularly woody vegetation. Microclimatic parameters (solar radiation, air temperature, surface temperature, humidity and wind speed) have been measured on site to assess the impact of the urban street trees density in the hot and humid summer condition in June. The study area selected for this study was Adana city, because of having high population density, heavily built-up street and the critical and prevailing thermal issues (Akin et al, 2014). The population of Adana reached above 1.8 million in 2016 (Turkish Statistical Institute, 2016). Adana is a city with a hot and humid climate. The mean daily maximum air temperature is approximately 31 °C in July and August. During the summer months, the daily mean relative humidity remains high (above 80%), with values usually exceeding 85% during the night time. Because of the high humidity, cloudy conditions dominate the weather during the summer in Adana (Turkish State Meteorological Service, 2017). Therefore, we chose a site in Adana’s densely pedestrian populated and heavily built-up street as Turgut Özal Avenue for our simulation. With the aim to forecast the microclimatic changes within an urban environment, a simulation tool, ENVI-met, was used. Envi-met is a three-dimensional microclimate model designed to simulate the surface–plant–air interactions in an urban environment with a typical resolution of 0.5–10 m in space and 10 s in time. It calculates the dynamics of microclimate during a diurnal cycle [24 to 48 hours] using fundamental laws of fluid dynamics and thermos dynamics. Envi-met can be used to evaluate several aspects of urban canyons and the effects of vegetation on outdoor comfort and urban heat island mitigation several configurations were simulated. These vary depending on location, climatic conditions, building density and height, vegetation type and quantity. It can, therefore, be seen as a va

International Workshop on GeoInformation Science
GEOADVANCES

M. Unal C. Uslu M.F. Altunkasa