A tale of two cities: The influence of urban meteorological network design on the nocturnal surface versus canopy heat island relationship in Oklahoma City, OK, and Birmingham, UK

Abstract

Interest in the investigation of the relationship between surface heat island intensity (sUHII) and canopy heat island intensity (aUHII) (sUHII-aUHII relationship) is growing mainly because of the global availability of satellite-sensed land surface temperature (T s). It is hoped that if such a universal relationship can be found, it could compensate for the spatial discontinuity of air temperature (T a) measurements that currently exist due to a paucity of weather stations in urban areas. In an attempt to investigate differences in the relationship in different urban environments, this study attempts to compare the linear sUHII-aUHII relationship between Oklahoma City, OK, and Birmingham, UK, based on the observations from Moderate Resolution Imaging Spectroradiometer and two dense urban meteorological networks (UMNs). Regression models and confidence ellipse, with two statistical tests, are applied in the comparison analysis under different climatic conditions with respect to specific ranges of wind speed (WS) and daily-accumulated solar radiation (DASR). Some general patterns of the linear sUHII-aUHII relationship are found across the two cities, such as the reduced rate of change of aUHII with respect to sUHII with increasing WS and the non-negligible advection effect in this relationship. Meanwhile, the differences of the linear sUHII-aUHII relationship across two cities are reduced under ideal conditions (clear skies, calm and large input of solar radiation from previous day into urban system). More importantly, the results emphasize the influence of the configuration of UMNs on the sUHII-aUHII relationship. By removing the climatic element in the relationship (i.e., WS and DASR), the impacts of the different local environments, source areas, and general configurations of the UMN become evident, indicating that a standardized protocol for the designs of UMN is the prerequisite for the generalization of the sUHII-aUHII relationship across cities.

Strong regulation of daily variations in nighttime surface urban heat islands by meteorological variables across global cities

“…The day-to-day variation of SUHI can also be dominated by meteorological variables (Lai et al 2021b), owing to the surface-air interactions (Oke et al 2017). For instance, the wind can influence not only the near-SAT, but also the radiation cooling of land surface by altering the heat advection (Feng et al 2020). The wind reveals a direct influence on CUHI (He 2018); while it shows insignificant influence on SUHI until the wind speed reaches a certain level (Shaposhnikova 2017).…”

“…Literature surveys show that the meteorological controls on SUHI have an order of priority different from that of CUHI (Oke et al 2017). Despite these aspects, compared to the extensively acknowledged CUHI variations in response to meteorological variables changes (Oke et al 2017, Feng et al 2020, there is still a lack of sufficient investigations that quantify the empirical relationships between day-to-day SUHII variation (termed as SUHII dv ) and the dynamics of various meteorological variables.…”

Incorporating Heat Vulnerability into Local Authority Decision Making: An Open Access Approach

“…Birmingham hosted an urban meteorological network between 2012 and 2014 [73], and the city has been a focus for urban climate research [74], using remote sensing (e.g., [75,76]), modeling (e.g., [11,18,77], and land-based observations [78] or mixed methods [79,80]. Although, some of this work has been undertaken in collaboration with BCC, there has been a disconnect between academic research and local authority decision making, and to date, previous research outputs have not been embedded within city design and planning policies.…”

Diurnal Variation in Urban Heat Island Intensity in Birmingham: The Relationship between Nocturnal Surface and Canopy Heat Islands

“…Their findings confirmed the presence of urban heat islands in Delhi at night and highlighted the role of urban areas as regulators of temperature changes under lowwind conditions. Furthermore, Feng et al [21] compared the SUHII-CUHII relationship under different weather conditions in Oklahoma City, USA, and Birmingham, UK, using MODIS data and the Urban Weather Network. They also compared the canopy urban heat island and surface urban heat island of Beijing, China, based on MODIS data, considering the spatial scale of the city.…”