CAREER: USTAR-ST--Universalizing Similarity Theories coupling the AtmospheRe and Sloping Terrain

University Of California-Davis, Davis CA

Investigators

Abstract

Land-atmosphere interactions are fundamental physical processes that govern how surface conditions, such as roughness, temperature and moisture, influence the state of the atmosphere and vice versa. Hence, the ability to represent the physical process is important to atmospheric, climate and hydrologic numerical models. Current representations of land-atmosphere interactions were developed based on horizontal and homogeneous terrain with various simplified modification; therefore, they cannot represent the fundamental physical processes that arise from the atmosphere's interactions with the heterogeneous and sloping terrain, characteristic of mountains. The research is to advance fundamental knowledge and representation regarding the atmosphere's interactions with mountain terrain by analyzing field data collected from two past experiments and a new field experiment specially designed for mountain terrain. Through this project, the professor who leads the research will pique student interest in mountain meteorology by developing an experiential education module and an interactive web-based slope flow simulator. To addresses fundamental knowledge-gaps that limit prediction capabilities over mountain slopes, the research project will analyze field datasets to investigate how slope angle fundamentally modulates near-surface turbulent fluxes of momentum and heat over mountainous terrain. This new understanding will be used to develop new, data-driven, land-atmosphere exchange parameterizations that explicitly account for the effects of slope angle. A slope-flow layer model, coupling the one-dimensional momentum and heat balances, will be created to quantitatively evaluate the new parameterizations in comparison to the traditional, horizontal-terrain relations and to serve as the foundation for a web-based slope-flow simulator tool. In addition, since many mountain slopes are forested, the research will employ novel measurement techniques to investigate the fundamental thermo-mechanical impacts imposed by a heterogeneous forest canopy on the slope-flow-layer surface exchange fluxes and determine how they can be incorporated into the new, slope-angle-dependent turbulent flux parameterizations. The ability to parameterize surface fluxes over mountain slopes will significantly improve numerical weather forecasting, hydrologic and air quality models and remote sensing products, which are used to study environmental stressors that occur at surface-vegetation-atmosphere interfaces, threaten mountain ecosystems and have significant socio-economic implications, such as flood-drought cycles, glacier recession, vegetation stress, and wildfire hazards. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.