Dynamics and controls of urban heat sink and island phenomena in a desert city: Development of a local climate zone scheme using remotely-sensed inputs

Abstract

This study aims to determine the dynamics and controls of Surface Urban Heat Sinks (SUHS) and Surface Urban Heat Islands (SUHI) in desert cities, using Dubai as a case study. A Local Climate Zone (LCZ) schema was developed to subdivide the city into different zones based on similarities in land cover and urban geometry. Proximity to the Gulf Coast was also determined for each LCZ. The LCZs were then used to sample seasonal and daily imagery from the MODIS thermal sensor to determine Land Surface Temperature (LST) variations relative to desert sand. Canonical correlation techniques were then applied to determine which factors explained the variability between urban and desert LST. Our results indicate that the daytime SUHS effect is greatest during the summer months (typically ~ 3.0°C) with the strongest cooling effects in open high-rise zones of the city. In contrast, the night-time SUHI effect is greatest during the winter months (typically ~3.5°C) with the strongest warming effects in compact mid-rise zones of the city. Proximity to the Arabian Gulf had the largest influence on both SUHS and SUHI phenomena, promoting daytime cooling in the summer months and night-time warming in the winter months. However, other parameters associated with the urban environment such as building height had an influence on daytime cooling, with larger buildings promoting shade and variations in airflow. Likewise, other parameters such as sky view factor contributed to night-time warming, with higher temperatures associated with limited views of the sky.

Satellite Remote Sensing of Surface Urban Heat Islands: Progress, Challenges, and Perspectives

“…The coverage, density, and materials of specific built-up land cover elements (e.g., buildings, roads, and parking lots) have also been related to SUHIs [82,94,[153][154][155][156][157]. Furthermore, 3D indicators such as the building heights and volumes, the frontal area index (FAI), the floor area ratio (FAR), and the sky view factor (SVF) are regularly used to represent the effects of urban morphology on SUHI [94,102,153,156,158,159]. When comparing the linkage between 2D/3D USCs and SUHIs, it is worth noting that correlation statistics might be biased in favor of 2D USCs.…”

“…In addition to urban vegetation, the presence and proximity of water bodies are known to have a cooling effect on urban temperature [62,103,106,[140][141][142]166]. However, impacts of the water body have been quantified by few indicators such as the normalized difference water index (NDWI) [116,167] and the distance between water bodies (or the coastline) and built-up land [142,158,165,168].…”

Scale response of summer urban heat island to building plot ratio and its warning parameter

“…Nassar considered Dubai as a case to study the phenomenon of collection and island of UHI by remote sensing. The study shows that the open, high-rise urban area exhibits a good cooling effect, and building height and shadow influence UHI [17]. The conclusion again suggests the close relationship between plot ratio and UHI.…”

Urban heat island behaviors in dryland regions

“…Schatz and Kucharik ). However, an emerging literature indicates that UHI dynamics are more complicated for dryland cities, a category that includes arid, semi-arid, and Mediterranean climates (Connors et al 2013, Nassar et al 2016. While there are a multitude of studies that focus on temperate regions there are less that focus on dryland regions and even fewer that do a global comparison.…”

“…High-density urban parcels with buildings that create shade can reduce local heating (Emmanuel and Fernando 2007, Norton et al 2015, Nassar et al 2016, 2017. Street width, building height, and tree canopy level all affect this dynamic (Coseo and Larsen 2014).…”