Urban-Rural Surface Temperature Deviation and Intra-Urban Variations Contained by an Urban Growth Boundary

Abstract

The urban heat island (UHI) concept describes heat trapping that elevates urban temperatures relative to rural temperatures, at least in temperate/humid regions. In drylands, urban irrigation can instead produce an urban cool island (UCI) effect. However, the UHI/UCI characterization suffers from uncertainty in choosing representative urban/rural endmembers, an artificial dichotomy between UHIs and UCIs, and lack of consistent terminology for other patterns of thermal variation at nested scales. We use the case of a historically well-enforced urban growth boundary (UGB) around Portland (Oregon, USA): to explore the representativeness of the surface temperature UHI (SUHI) as derived from Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature data, to test common assumptions of characteristically “warm” or “cool” land covers (LCs), and to name other common urban thermal features of interest. We find that the UGB contains heat as well as sprawl, inducing a sharp surface temperature contrast across the urban/rural boundary. The contrast ranges widely depending on the end-members chosen, across a spectrum from positive (SUHI) to negative (SUCI) values. We propose a new, inclusive “urban thermal deviation” (UTD) term to span the spectrum of possible UHI-zero-UCI conditions. We also distinguish at finer scales “microthermal extremes” (MTEs), discrete areas tending in the same thermal direction as their LC or surroundings but to extreme (hot or cold) values, and microthermal anomalies (MTAs), that run counter to thermal expectations or tendencies for their LC or surroundings. The distinction is important because MTEs suggest a need for moderation in the local thermal landscape, whereas MTAs may suggest solutions.

Remotely Sensed Derived Land Surface Temperature (LST) as a Proxy for Air Temperature and Thermal Comfort at a Small Geographical Scale

“…To illustrate, [45] examines the impacts of urban functional zones and spatial heterogeneity on LST in Beijing, China; Temporal changes in LST as a result of urban redevelopments in Lyon, France where investigated by [46]; and the impacts of different types of LULC patterns on SUHI variations in Bangkok, Thailand, where evaluated by [47]. Similarly, the impacts of the composition of different types of land cover on SUHI have been examined in the cases of Austin and San Antonio, Texas [48] and Portland, Oregon [49]. Recently, [50] estimated patterns of LST over King Abdulaziz University campus (Jeddah, Saudi Arabia), demonstrating the potential of Landsat-derived LST estimates to map long-term changes of the UHI phenomenon at a geographical scale of a university campus.…”

Beyond growth management: A review of the wider functions and effects of urban growth management policies

“…For example, Gilchrist, Barker, & Handley (2016) investigated the range expansion of butterflies; here the GB was a study location, but not the focus in its own right. Other studies applied new methodological approaches, using UGMPs zones as case studies to test them (Moffett, Makido, & Shandas, 2019).…”

“…Multiple regulating functions relating to climate were identified in the US and Asia from UGMPs, showing their potential to contribute to climate mitigation and adaptation, including a reduction in urban heating in the US and Korea (S. Jeon, Hong, & Kang, 2018;Moffett et al, 2019;) and increased carbon sequestration through landscape protected (Cathcart, Kline, Delaney, & Tilton, 2007;S. Jeon, Hong, & Kang, 2018;McDonald-Buller, Webb, Kockelman, & Zhou, 2010;Moffett et al, 2019). Additionally, UGMPs indirectly contributed to air pollution mitigation by reducing vehicle miles travelled and associated emissions (S. Jeon et al, 2018;McDonald-Buller, Webb, Kockelman, & Zhou, 2010).…”

Coupling Ecological Security Pattern Establishment and Construction Land Expansion Simulation for Urban Growth Boundary Delineation: Framework and Application

“…Staley believes that the purpose of the UGB is to guide the optimization of spatial patterns to restrain disorderly urban sprawl and further validates his view with the case of the UGB delineation in Portland [32]. Since then, the UGB has emerged as one of the most important approaches for optimizing the spatial pattern of cities around the world, with countries such as the United States [27,33], Switzerland [22], and Iran [34,35] all finding that the UGB is an effective tool to control the disorderly sprawl of cities. On this basis, subsequent studies have paid significant attention to the UGB in both theory and practice [36].…”