The impact that climate change and urbanization are having on the thermal-energy balance of the built environment is a major environmental concern today. Urban heat island (UHI) is another phenomenon that can raise the temperature in cities. This study aims to examine the UHI magnitude and its association with the main meteorological parameters (i.e., temperature, wind speed, and wind direction) in Dubai, United Arab Emirates. Five years of hourly weather data (2014–2018) obtained from weather stations located in an urban, suburban, and rural area, were post-processed by means of a clustering technique. Six clusters characterized by different ranges of wind directions were analyzed. The analysis reveals that UHI is affected by the synoptic weather conditions (i.e., sea breeze and hot air coming from the desert) and is larger at night. In the urban area, air temperature and night-time UHI intensity, averaged on the five year period, are 1.3 °C and 3.3 °C higher with respect to the rural area, respectively, and the UHI and air temperature are independent of each other only when the wind comes from the desert. A negative and inverse correlation was found between the UHI and wind speed for all the wind directions, except for the northern wind where no correlation was observed. In the suburban area, the UHI and both temperatures and wind speed ranged between the strong and a weak negative correlation considering all the wind directions, while a strong negative correlation was observed in the rural area. This paper concludes that UHI intensity is strongly associated with local climatic parameters and to the changes in wind direction.

The cities of desert climates are anticipated to recognize a synergy of urban heat island (UHI) and severe heat waves during summertime. To improve the urban thermal environment, the present study aims quantitatively explore a strategically designed network of vegetation patches called green infrastructure (GI) in subtropical desert cities such as Dubai. To achieve a more comfortable temperature environment, we built and simulated four GI situations with higher GI fractions, GI25, GI50, GI75, and GI100. Using a mesoscale urban model, the mosaic approach is utilized to test potential thermal improvement and urban climate impact, and a portion of each urban grid cell in the model domain is altered with various species of urban vegetation patches by 25%, 50%, 75%, and 100%. The daily peak reduction in ambient temperature at 17:00LT is similar to 0.0168 °C per unit of GI increase when compared to the untreated scenario; however, the maximum anticipated daytime summer temperature decline for GI25, GI50, GI75, and GI100 is 0.6 °C, 1.1 °C, 1.4 °C, and 1.7 °C, respectively. The associated reduction in nighttime ambient temperature per unit increase in the GI is 0.0432 °C, with a maximum temperature drop of around 2.4 °C for the GI100 scenario. Increased GI reduces the height of the planetary boundary layer (PBL) by up to 468 m, which might lead to greater pollution concentrations. While GI-based cooling has a significant influence on delayed sea breeze and humidity, it may raise the risk of heat discomfort in the indoor building environment. This study adds to our understanding of the potential for GI mitigation as well as the seasonal impact of developing GIs on the desert urban boundary layer.

Due to urban warming, the energy demand for cooling buildings is rising. The current study used CitySim (building energy model) to estimate the cooling energy requirements for 40 buildings in downtown Dubai using high-resolution climate data from weather research and forecasting (WRF) coupled with the single layer urban canopy model (SLUCM). Simulating the four mitigation scenarios allowed for the examination of the reduction in cooling load caused by the addition of greenery at a rate ranging from 25% to 100%. The insulated building’s cooling demand reduced by a maximum of 13.89% under 100% GI (M4). Scenario M4 resulted in a reduction of 4.6 kWh/m² and 3.1 kWh/m² for the non-insulated and insulated low-rise residential buildings, respectively, while the high-rise buildings saw a reduction of 3.09–4.91 kWh/m² for the non-insulated and 2.07–3.09 kWh/m² for the insulated buildings. This study offers a potential remedy to deal with the problem of urban heating in subtropical environments.

Due to urban warming, energy demand for cooling buildings is rising. The current study used CitySim to estimate the cooling energy requirements for 40 buildings in Downtown, Dubai using high-resolution climate data from weather research and forecasting (WRF) coupled with single layer urban canopy model (SLUCM). Simulating the four mitigation scenarios allowed for the examination of the reduction in cooling load caused by the addition of greenery at a rate ranging from 25% to 100%. The insulated building's cooling demand reduced by a maximum of 13.89% under 100% GI (M4). Scenario M4 resulted in a reduction of 4.6 kWh/m2 and 3.1 kWh/m2 for the non-insulated and insulated low-rise residential buildings, respectively, while the high-rise buildings saw a reduction of 3.09-4.91 kWh/m2 for the non-insulated and 2.07-3.09 kWh/m2 for insulated buildings. This study offered a potential remedy to deal with the problem of urban heating in subtropical environments.