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Cities increasingly recognize the importance of shade to reduce heat stress and adopt urban forestry plans with ambitious canopy goals. Yet, the implementation of tree and shade plans often faces maintenance, water use, and infrastructure challenges. Understanding the performance of natural and non-natural shade is critical to support active shade management in the built environment. We conducted hourly transects in Tempe, Arizona with the mobile human-biometeorological station MaRTy on hot summer days to quantify the efficacy of various shade types. We sampled sun-exposed reference locations and shade types grouped by urban form, lightweight/engineered shade, and tree species over multiple ground surfaces. We investigated shade performance during the day, at peak incoming solar, peak air temperature, and after sunset using three thermal metrics: the difference between a shaded and sun-exposed location in air temperature (ΔTa), surface temperature (ΔTs), and mean radiant temperature (ΔTMRT). ΔTa did not vary significantly between shade groups, but ΔTMRT spanned a 50°C range across observations. At daytime, shade from urban form most effectively reduced Ts and TMRT, followed by trees and lightweight structures. Shade from urban form performed differently with changing orientation. Tree shade performance varied widely; native and palm trees were least effective, while non-native trees were most effective. All shade types exhibited heat retention (positive ΔTMRT) after sunset. Based on the observations, we developed characteristic shade performance curves that will inform the City of Tempe’s design guidelines towards using “the right shade in the right place” and form the basis for the development of microclimate zones (MCSz).

Extreme temperatures claim more lives than any other weather-related event, posing escalating socio-technical and governance challenges that few urban communities have addressed in a systematic, coordinated and comprehensive way. Scholars have only recently begun to investigate the granular scales at which distributions of thermal risk are produced, people's individual subjective thermal experiences and environmental justice dimensions of the hazard. Advances in research pave the way for concomitant improvements in management and policies, but bridges are needed to connect the thermal vulnerability knowledge base with place-based protective practices that are climatically, politically and culturally appropriate. The research presented in this paper uses actor-network theory (ANT) to describe the planning phase framework of a socio-technical collaborative for managing thermal extremes. The Thermally Resilient Communities Collaborative (TRCC) is a framework for planning and test-bed design phases of a thermal management system. Drawing lessons from two case studies, the framework examines how socio-cognitive spaces for collaboration change with technical and policy disruptions, and provides a way to design experiments that test how technical and governance interventions can enable collective action around urban thermal management. Practice relevanceThermal extremes claim more lives than all other weather events and pose an escalating socio-technical challenge. Often the problem is exacerbated by lack of clarity about organizational responsibilities and coordination between local governmental departments or agencies. The TRCC framework can be used to understand current practices, identify data gaps and create opportunities to engage in cross-sectoral management. This approach engages actors in identifying built environments and societal practices that create hazardous indoor and outdoor thermal conditions, develops effective ways to convey microclimate information and peoples' subjective thermal experiences to responders and prevention planners, and elevates experiences of marginalized communities. The TRCC describes how governance networks are harnessed to solve collective action problems by integrating new data, technology, and governance capacities. Two case studies indicate how this process was used to create capacities to protect vulnerable people from the impacts of extreme temperatures in two US cities: Tempe, Arizona, and Buffalo, New York.Thermally resilient communities 219 1. Background Thermal extremes pose an escalating socio-technical and governance challenge in cities across the globe. In the United States, prolonged periods of heat and cold claim more lives than all other weather-related events (Berko et al. 2014) and have significant impacts on urban ecosystems and infrastructure. Approximately 30% of the world's population is exposed to deadly heat and humidity for at least 20 days per year, and that percentage is expected to increase to 48-74% by 2100, depending on what emissions scenario occurs (M...

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<p>Urban morphological attributes and surface properties can largely influence near-surface air temperatures. Unpacking such <em>morpho-thermal</em> relationships are of particular importance in hot urban desert (HUDs) cities given the already extreme thermal bioclimatic dynamics, urban-induced heating with rapid urbanization processes, and vulnerability of residents. Satellite-derived investigations may underestimate critical system dynamics of urban thermal stimuli found within sub-diurnal phenomena and sub-meter classifications. High resolution spatiotemporal measurements are therefore required to objectively assess latent magnitudes of heat mitigation and amelioration strategies. This study utilized the natural heterogeneity of morphometric predictors with fixed ground-based measurements in a representative neighborhood unit typology within Kuwait’s residential landscape to build a composite dataset of sub-hourly air temperature measurements with sub-meter morphological attributes. The presentation will share initial findings of the study and preliminary analysis of the drivers of heating/cooling rate’s association to defined morphological factors.</p>