Numerical evaluation of enhanced green infrastructures for mitigating urban heat in a desert urban setting

Abstract

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.

Quantifying the energy impact of heat mitigation technologies at the urban scale

“…16). By lowering the urban surface temperature, the height of the planetary boundary layer may decrease, resulting in reduced heat advection from the desert 24 .…”

Assessing Spatial Heterogeneity in Urban Park Vitality for a Sustainable Built Environment: A Case Study of Changsha

“…It is a crucial metric for assessing the quality of urban life and the capacity for sustainable development. Researchers delineate vitality through diverse factors such as heatmap data [44], mobile signaling data [44], nighttime light data [45], and online check-in data [42,46].…”

The use of green infrastructure and irrigation in the mitigation of urban heat in a desert city

“…The warmer climate, expanding urban boundaries and increasing population have created unprecedented hot weather in cities (Santamouris 2023a(Santamouris , 2023b. Urban overheating is imposing detrimental effects on energy consumption (Santamouris 2014b;Khan et al 2023a;Mohammed et al 2023a), and peak electricity demand (Sigauke and Nemukula 2020). Studies on major US cities have shown that a 1 °C increase in temperature, once it exceeds 15-20 °C, results in a 2%-4% increase in peak electricity demand (Cao et al 2010).…”