On Tuesday, December 5, from 12:00–1:00 pm please join us for the next Spatial Technology Lunch in the Center for Spatial Studies (Phelps Hall 3512). This semi-regular series, hosted by spatial@ucsb, aims to promote discussion and interaction within the university’s spatial technology community. Please RSVP to Crystal Bae (cbae@spatial.ucsb.edu) by Sunday, December 3. Pizza and drinks will be provided.

Evaluating vegetation type effects on land surface temperature at the city scale

Erin Wetherley

Wetherley Tech Lunch
Abstract: The growing concentration of the global human population into cities has coincided with the rise of increasingly rich remote sensing data. Near-future hyperspectral/thermal satellites could revolutionize our understanding of urban environments by allowing us to discriminate urban materials and examine their thermal properties. With this wealth of information, we will be able to disentangle the links between land cover, management, and climate at the city scale for the very first time, with significant consequences for improved modeling of urban climate, energy, and water use, as well as targeted urban planning and public health initiatives.

I will present new results in which we sampled the material and thermal heterogeneity of the Los Angeles, CA, metropolitan area (4,283 km2) to quantify, analyze, and model surface drivers of urban heat. We used airborne hyperspectral imagery (AVIRIS: 36 m resolution, 224 bands, 0.35 – 2.5 μm) to produce robust estimates of fine-scale (sub-pixel) urban patches, defined as mixtures of key urban surface classes. We then used airborne MASTER thermal imagery to quantify and model surface temperature changes as patch mixtures transitioned from low to high proportions of vegetation. Significant differences were observed between tree, turfgrass, senesced vegetation, and impervious mixtures. Finally, we used our modeled and measured temperatures to observe and quantify additional urban microclimate drivers beyond urban patch type, including income levels, building fraction, and irrigation.

Erin Wetherley is a Ph.D. student at UCSB.