Modeling Thermal Flows and Cold-air Pools in a Small Basin

University Of Utah, Salt Lake City UT

Investigators

Abstract

The goal of this project is to advance the scientific understanding of (1) thermally driven cross-basin flows and how they are modified by heterogeneous vegetation and snow coverage and by larger-scale flows and of (2) nocturnal inflows and outflows through gaps and saddles in the surrounding topography of basins and how they interact with existing cold-air pools. This work has strong potential to improve air quality forecast and transportation safety. This research project will study selected aspects of thermally driven flows and cold-air pools in the Gruenloch, a small Alpine basin. Numerical model simulations are designed to answer questions that are yet poorly understood. The project will be performed in collaboration with scientists at the University of Vienna, Austria, who have been collecting data in the Gruenloch basin for the past 12 years and who plan another, more extensive field program. The topography of the Gruenloch basin and its surroundings is ideally suited for this study. The Gruenloch is known for the development of strong cold-air pools and extreme minimum temperatures, holding the record for the lowest measured temperature in central Europe. The complex topography of the surrounding Alps, including several saddles in the ridgeline of the Gruenloch, allow the formation of larger-scale daytime and nighttime flows that interact with the basin atmosphere. Intellectual Merit : The results from this study will advance the understanding of several aspects of thermally driven flows and cold-air pools, which occur frequently in mountainous terrain. The defined questions about the influence of surface conditions and flows induced by the complex surrounding topography on cross-basin flows and the influence of basin outflows and inflows on cold-air pools are yet poorly understood. Observational data will be used to evaluate and improve high-resolution modeling performance in this highly complex terrain. Broader Impacts : The scientific findings from this study will advance knowledge on thermally driven flows and cold-air pools that can contribute to improved forecasting of these phenomena, which strongly affect air pollution transport and dispersion, noise propagation, fire propagation, and fog formation in mountainous terrain. Results will be made public through journal publications, conference and invited seminar presentations, and websites. Findings will be incorporated into classroom lectures.