Characterizing the Hourly Variation of Urban Heat Islands in a Snowy Climate City during Summer

Abstract

Temporal variation of urban heat island (UHI) intensity is one of the most important themes in UHI studies. However, fine-scale temporal variability of UHI with explicit spatial information is sparse in the literature. Based on the hourly air temperature from 195 meteorological stations during August 2015 in Changchun, China, hourly spatiotemporal patterns of UHI were mapped to explore the temporal variability and the effects of land use on the thermal environment using time series analysis, air temperature profiling, and spatial analysis. The results showed that: (1) high air temperature does not indicate strong UHI intensity. The nighttime UHI intensity (1.51 °C) was much stronger than that in the daytime (0.49 °C). (2) The urban area was the hottest during most of the day except the period from late morning to around 13:00 when there was about a 40% possibility for an “inverse UHI intensity” to appear. Paddy land was the coolest in the daytime, while woodland had the lowest temperature during the nighttime. (3) The rural area had higher warming and cooling rates than the urban area after sunrise and sunset. It appeared that 23 °C was the threshold at which the thermal characteristics of different land use types changed significantly.

Analysis of air temperature dynamics in the “local climate zones” of Novi Sad (Serbia) based on long-term database from an urban meteorological network

“…The HR are smaller during the second heating phase, yet an interesting pattern was noticed: the highest HR were observed in street canyons of LCZ 2, while lower HR were observed in more open LCZs 3 and 5, and in natural LCZ A. Yang et al (2019) also reported that the urban area had higher HR than rural areas during midday and in early afternoon hours, while the opposite was during the morning hours in Changchun (China).…”

“…Accordingly, it is important to analyze HR changes for a comprehensive UHI research. Although CR are more frequently studied (e.g., Oke and East 1971;Oke and Maxwell 1975;Lee 1979;Johnson 1985;Eliasson 1994;Haeger-Eugensson and Holmer 1999;Holmer et al 2007;Leconte et al 2017;Skarbit et al 2017) than HR, this study will be one of the few to investigate HR in various LCZs (e.g., Skarbit et al 2017;Gonçalves et al 2018;Yang et al 2018;Yang et al 2019).…”

Evaluating the Effects of Environmental Conditions on Sensed Parameters for Green Areas Monitoring and Smart Irrigation Systems

“…They identify lower values from 5 to 6 AM in all the studied points and two peaks at 12 PM and 6 PM. Temporal variation of urban heat island (UHI) was studied in [ 9 ]. Their results indicate that UHI can be used as an indicator or urban or rural areas.…”

Analysis of Urban Heat Island and Heat Waves Using Sentinel-3 Images: a Study of Andalusian Cities in Spain

“…In recent decades, numerous studies warn that the transformation of the landscape owing to the expansion of urban areas is one of the processes that contributes most to climate change (Li et al 2011 ; Carvalho et al 2017 ; Jiang et al 2019 ; Yang et al 2019 ; Song et al 2020 ). Changes in land cover increase the surfaces of impermeable materials, such as asphalt and concrete, reducing evapotranspiration (Stewart and Oke 2012 ).…”