Background climate regulates importance of green and bluespace for urban cooling
Abstract
The prevalence of impermeable surfaces in urban regions gives rise to an urban heat island (UHI) effect, wherein developed areas have higher temperatures than surrounding undeveloped areas. The intensity of urban heat can vary, however, both among cities and within cities. This range in UHI intensity among cities is largely driven by variability in climate regimes and humidity: compared to cities in arid regions, cities in humid regions can exhibit higher temperatures in the urban core relative the surrounding area. Within-city variability, in contrast, is driven in large part by interspersion of blue-green infrastructure, such as tree canopy, ground-level vegetation, and water. The extent to which factors that drive among-city variability (i.e., background climate, humidity and temperature) also impact the cooling benefits of blue-green infrastructure is, however, less studied. In this study, we evaluate the sensitivity of green and blue space configuration metrics for urban cooling across cities with different background climates. We explore this through spatial analysis of summer land surface temperatures (LSTs) and landscape pattern metrics related to green space (ground level and canopy cover) and blue space (water bodies) across ten US cities that exhibit a range of climatic conditions. Using a moving window approach across each city, we (i) compute the difference between LST within each window and background LST (LST) ; and (ii) compute class-level metrics (e.g., fraction of window comprised on blue space, blue space patch density) within each window. For each city, we then explore the relationships between LST and class-level landscape pattern metrics. Preliminary results show that both the magnitude and distribution of within-city of LST varies among humid and arid cities, with humid cities exhibiting a wider range, but also more uniform distribution of within-city LST. Additionally, the importance of different landscape pattern metrics and landscape classes (green space, canopy cover, and blue space) for predicting LST vary among very humid and very arid cities. Understanding the sensitivity of urban cooling mitigation efforts to background climate will aid in the development of interventions that are protective of human health and vulnerable populations.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.H34H..08S