Faeze Shoja, Salimeh Sadeghi, Shamsipour,
Volume 0, Issue 0 (3-1921)
Abstract
The aim of this research is to evaluate the heat mitigation index (HMI) in the Tehran metropolitan area using the Urban Cooling Model(UCM)approach in a spatial framework. UCM produces maps of the Heat Mitigation Index. This index estimates the cooling potential of urban green spaces in a given location, taking into account various parameters such as evapotranspiration, tree shading, albedo, rural reference air temperature, urban heat island intensity, air temperature maximum blending, and maximum cooling distance. The assessment of environmental factors influencing the UCM in the study area revealed that the urban heat island effect was least intense in regions 1, 22, and the northern parts of region 4 of Tehran municipality, where there are scattered trees, shrubs, open low-rise buildings, and water bodies. The temperature differential between the city and the suburbs ranged from 0 to 1.3 degrees Celsius. However, the study area's central parts showed the highest intensity of the urban heat island, particularly in regions 21, 13, and 14. These regions have a dense and compact texture and an expansion of impervious surfaces, resulting in the lowest values of the evapotranspiration index and albedo.Based on these parameters, the study area's HMI index showed that the cooling capacity varies from 0.08 in the central parts of the city to 0.9 in areas affected by green spaces and water bodies. The maximum cooling capacity index is concentrated in areas with dense and scattered tree cover in the region. On average, these areas have been able to neutralise 2.48 degrees Celsius of the urban heat island effect with a cooling capacity of 63%. The methodology employed in this research can be used as a reference for urban designers in integrating urban cooling approaches and heat island mitigation strategies in urban planning and design.
Mr Sirous Hashemi Darebadami, Dr Ali Darvishi Boloorani, Dr Seyed Kazem Alavipanah, Mr Mohammad Maleki, Mr Reza Bayat,
Volume 19, Issue 52 (3-2019)
Abstract
The term urban heat island (UHI), described the phenomenon of climate change in urban areas compared with surrounding rural areas. UHI effects include: increasing in energy and water consumption, air pollution expansion and interfering in thermal comfort. Surface urban heat island (SUHI) contains patterns of land surface temperature (LST) in urban areas that has interaction with UHI in urban canopy layer and urban boundary layer and investigate with thermal remote sensing. SUHI has diurnal and seasonal variations so requires multi-temporal data to analysis SUHI. In this study, the multi-temporal MODIS (Aqua and Terra) data product were used to analyze the SUHI in day and night in Tehran metropolitan. Physical and biophysical surface properties such as: land cover/land use (LULC), elevation, albedo, vegetation index (NDVI) and impervious surfaces index (NDBI) were used to interpretation of the LST and SUHI changes. The results showed that SUHI in Tehran, has spatial-temporal diurnal and seasonal variation. So that during warm days the surface urban cool island (SUCL) is formed in Tehran. At night times, SUHI index values was different between 2 and 5 ° C (maximum in the spring). The results also showed that different of land cover thermal properties, albedo and elevation was the most important factors is the diurnal changes of SUHI while phonological changes of vegetation and albedo, was the most important factors in seasonal changes of SUHI.
