Characterizing Urban Surface–Atmosphere Interactions
Thunderstorms and cold snaps, high winds and humidity—almost everything we experience as weather arises in the low-lying portion of the atmosphere called the atmospheric boundary layer (ABL). Interactions between the Earth’s surface and the ABL cause rapid changes in atmospheric conditions: Forests and deserts absorb and radiate heat; hills and trees disturb air currents; and, depending on the circumstances, soils and bodies of water can absorb or release carbon dioxide and other gases.
Surface-atmosphere interactions that occur over vegetated canopies, such as forests and jungles, have been extensively studied and described. But the effects of cities, which arise both from their physical attributes and from the human activities that occur there, are not fully understood and remain a challenge to model. With this CAREER award, Qi Li, Civil and Environmental Engineering, is characterizing the movement and exchange of heat and mass between cities and the ABL. This project will consider particularities of urban spaces—such as street canyons, solid buildings, and human-generated carbon emissions that are unconstrained by plants’ biophysical processes—that make cities distinct from vegetated canopies.
This research will produce widely adaptable computational models that account for the unique attributes of different cities. Understanding the dynamics that govern the movement and exchange of heat and mass between cities and the ABL is crucial for the development of accurate, high-resolution weather and climate models. The physically realistic, generalizable estimates of urban surface–atmosphere exchanges produced by this research could contribute to fine-scale climate and predictive weather models that are needed to formulate city- and neighborhood-specific measures to mitigate and adapt to climate change.