Analysis of winter thermal comfort conditions: street scenarios using ENVI-met model

Assessment of the impact of the different settlement patterns on the summer land surface temperature: Elazığ

Currently, cities are at the center of the debate on global warming since land use and land cover change (LULC) in cities are considered to be major contributors to global climate change. In this study, Çarşı and Doğukent Neighborhood areas in the city center of Elazığ province, Turkey, were examined in terms of land use and land cover (LULC). Both areas were chosen because they have different patterns and features, such as different residential densities, street aspect ratios and orientations, impervious surfaces, vegetation, and elevations. The aim is to assess the effect of the different patterns of these settlements on the land surface temperature (LST) using Landsat 8 satellite images in the summertime, July 19, 2021. The results showed that the maximum, minimum, and average LST of the Doğukent Neighborhood, which is characterized by uniform streets with dense vegetation and streets oriented to the NE-SW or NW-SE, were recorded as 44.4, 38.4, and 41.0 °C, respectively, while 45.4, 40.4, and 43.8 °C were recorded in the Çarşı Neighborhood characterized by excessive residential areas and deep streets with lack of vegetation oriented to the E-W direction. However, the average difference is around 2.8 °C, implying that residential areas with mid-building heights and vegetated streets oriented to NE-SW or NW-SE are thermally better than those with high aspect ratio streets and lacking vegetation and oriented to E-W. It was found that small variations in land elevation of these areas do not significantly affect the LST. The results of this study will set an example not only for the city of Elazığ, but also for the determination of urban transformation areas, new housing areas, and climate change in most cities of Turkey and other countries, and will provide support for sustainable and more livable urbanization in most cities. Transferring the data obtained by local governments to the physical plan decisions could also contribute to preventing climate change.

Effect of outdoor thermal comfort condition on visit of tourists in historical urban plazas of Sevilla and Madrid

The tourism plays a significant role in economics and development of any country through revenue generation from multiple sources. Spain has been tourist place and host million foreign tourist. The tourism is highly depended on climate and thermal comfortness of the visiting place. This present research aimed to analyze the outdoor thermal comfort conditions in microclimates of the urban ancient plazas of the two important cities of Spain, namely Sevilla and Madrid on a hot humid stress day of the year. The microclimatic measurement, questionnaire survey, and simulation results were examined to evaluate the thermal comfort condition of six different urban plazas in Sevilla and Madrid to distinguish the supreme time to visit each ancient site. The results have suggested that the outdoor thermal comfort range for the tourist in the historical plazas of Sevilla and Madrid varies from 28.42 to 30.87 °C and 24.5 to 29.82 °C in the hot summer. Despite the high heat stress condition, the result of questionnaires survey shows that about 38.11% and 28.09% of tourists in Sevilla and Madrid, respectively, were satisfied with the thermal conditions. As witnessed from the result of the Envi-met simulation, Plaza de Santa Ana of Madrid and Plaza Nueva of Sevilla is the best place for visitors in the early morning hours. Additionally, during the peak hours, the thermal comfort of Alameda de Hercules of Sevilla and Plaza de Santa Ana of Madrid is the most suitable historical places for visitors, whereas in the evening hours, Plaza Nueva of Sevilla and Plaza de Mayor of Madrid with wider semi-open spaces and relatively suitable vegetation bring more favorable conditions for visitors. The comparison of the simulation result with the questionnaire reveals that the urban plazas with relatively high thermal stresses have a higher rate of thermal dissatisfaction.

Microclimatic and Environmental Improvement in a Mediterranean City through the Regeneration of an Area with Nature-Based Solutions: A Case Study

Dense urban areas are facing relevant issues related to their high vulnerability to the impacts of climate change and ecosystem health. The study presents a case study of a regeneration project with Nature-based Solutions in the city of Genoa (Italy) and, more specifically, in a neighbourhood characterised by relevant health and well-being issues. The performances of three design scenarios for a city hotspot, including plant species selected with a systemic approach and light pavements, are analysed in terms of improved microclimate by means of the ENVI-met software V4.4.5. The results show different benefits on the microclimate compared to the current state depending on the different scenarios: A UTCI decrease from 4.1 °C to 5.4 °C, a reduction of mean radiant temperature from 12.3 °C to 17.3 °C, a relative humidity increase from 3.8% to 5.6%, and a progressive decrease in wind speed are detected in a directly proportional way to the gradual increase in greenery inside the scenarios. In reverse, better results for air temperatures are detected for the scenario with less greening (Δt = 1.8 °C). The study relies on the re-parametrisation of plant species characteristics in the ENVI-met database to reach a high level of accuracy.

Quantifying Interactive Cooling Effects of Morphological Parameters and Vegetation-Related Landscape Features during an Extreme Heat Event

In this study, we apply the ENVI-met model to evaluate the effects of combinations of morphological and vegetation-related landscape features on urban temperatures and thermal comfort. We simulated the thermal conditions of 126 scenarios, varying the aspect ratios of street canyons, vegetation cover and density, surface materials, and orientations toward the prevalent winds under an extreme heat situation. Our results show how the effects of physical and vegetation parameters interact and moderate each other. We also demonstrate how sensitive thermal comfort indices such as temperature and relative humidity are to the built environment parameters during different hours of a day. This study’s findings highlight the necessity of prioritizing heat mitigation interventions based on the site’s physical characteristics and landscape features and avoiding generic strategies for all types of urban environments.

Environmental Effects from Pocket Park Design According to District Planning Patterns—Cases from Xi’an, China

Rapid urban expansion leads to the continuous deterioration of the urban thermal environment, which endangers the sustainable development of the city; meanwhile, countries all over the world are becoming increasingly interested in the mitigating effects of urban green spaces on heat islands. In this context, many studies show that pocket parks play an important role in optimizing the thermal environment of urban blocks, especially with the high-intensity development of urban blocks. Moreover, many cities in China have become mature, and it is difficult to open up large green areas. Therefore, to improve the urban thermal environment in summer, it is necessary to adapt to an efficient pocket-park design strategy in blocks. To consider the impact of block development intensity on the design strategy of pocket parks, three pocket parks in blocks with different floor-area ratios in the central area of Xi’an were selected as examples. This research compares the effects of tree density and green-space layout on the thermal environment in different floor-area ratio districts on a summer day using environmental simulation (ENVI-met). The results show that the design strategies of pocket parks in urban blocks with different development intensities are different. High tree density performs better from the perspective of improving the urban thermal environment. For the low and medium development intensity blocks, the effects of the open green space and closed green space are similar, while the open green space layout can significantly improve thermal comfort in high-intensity development blocks.