Transformative Climate Communities: Informing Adaptation Planning through Cool Urban Design Interventions in Southern California

Many hot regions anticipating even hotter temperatures under climate change have prioritized microclimate regulation in adaptation planning. Interventions such as trees, shade, and cool surfaces are promoted as a means to mitigate the urban heat island, improve public health, and reduce energy consumption, among other goals. Yet, the extent to which design interventions that theoretically regulate local microclimates effectively do so in the places in which they are implemented and for the suite of goals articulated is not well understood. This gap in understanding is due, in part, to relatively scarce field data collected at actual sites where climate adaptations are implemented. In Southern California, the Transformative Climate Communities (TCC) initiative founded as part of California’s Cap and Trade program is tasked with implementing climate adaptation design interventions to improve environmental, health, and economic outcomes in disadvantaged communities through community led processes. Interventions include tree planting initiatives, urban greening, passive cooling, and cool surfaces. TCCs are poised to become vital living laboratories for better understanding urban form-microclimate linkages due to the relatively short timeline (~5 year) for development and assured funding for physical projects. Integrating remote sensing and biometeorological field observations from three TCC sites (Watts, Ontario, and Fresno), this project addresses the central question: How do urban form interventions change microclimate and thermal comfort in neighborhoods? This question is addressed by analyzing the relationship between land cover and land surface temperature and modeling the effects of design intervention scenarios on thermal comfort in the study area and comparison sites over time. Specifically, (1) we quantify land composition and configuration using landscape metrics and relate them to land surface temperature, albedo, and vegetative cover in the study area and comparison sites. (2) We characterize thermal comfort through field observations using multiple sensing devices, including MaRTy, a mobile biometeorological instrument, to observe Mean Radiant Temperature and inform microclimate models that simulate the effects of planned design interventions on thermal comfort. By better understanding the microclimate outcomes of design interventions in situ, we aim to disambiguate the relative effectiveness of various interventions in achieving different environmental and human health outcomes and inform climate adaptation planning.