EESS talk on "Persistent Wintertime Cold-Air Pools and Particulate Air Pollution in Topographic Basins of Northern Utah"


Event details

Date 02.10.2018
Hour 12:1513:15
Speaker Dr Sebastian Hoch, Research Assistant Professor in Atmospheric Sciences, University of Utah, USA - visiting professor Dr Sebastian Hoch is a Research Assistant Professor at the University of Utah. He received his PhD at ETH Zurich in 2006. His research focuses on boundary layer processes in complex terrain. His interests start with differences in the radiation and surface energy balance and their resulting effects on boundary layer evolution, and range to the flows driven by these contrasts, and their complex interactions with terrain. His observational studies have covered topographic basins such as Arizona's Meteor Crater (METCRAX 2006, METCRAX-II), Utah's Bingham Canyon Mine Experiment, and the Salt Lake Valley (PCAPS, UWFPS), mountainous terrain in the Swiss Alps (DISCHMEX) and Utah's West Desert (MATERHORN), and addressed processes ranging from downslope windstorm type flows (METCRAX-II) to fog formation (MATERHORN-FOG, CFOG). Sebastian Hoch has special interest in wind lidar observations, clear-air radiative cooling, and the complex interaction between wintertime cold pool meteorology and air chemistry.
Category Conferences - Seminars
Persistent wintertime temperature inversions in mountainous areas around the world are a key factor leading to cold-season air pollution episodes, periods of freezing rain and drizzle, fog and haze, extreme temperature minima, and transportation and other weather-related societal problems. For example, under high pressure conditions during winter, strong persistent cold-air pools (PCAPs) frequently develop in the Salt Lake, Cache, and Utah Valleys in northern Utah, trapping and accumulating pollutants such as PM2.5 that have well-documented adverse health effects.
Several meteorological and air chemistry studies have been conducted in the past years and have highlighted the complex interaction between meteorological and chemical processes. This presentations will summarize the results of these past observations and the unique processes taking place in the Salt Lake Valley. Observational data include chemical measurements of particulate matter and chemical precursor gases, highlighting possible reactive pathways from stationary and mobile platforms. Besides surface based weather stations, meteorological data sets include the twice-daily radiosondes from the Salt Lake airport, pseudo-vertical temperature soundings based on inexpensive temperature data loggers placed along the basin sidewalls, aerosol backscatter from ceilometers, sodar, and wind lidar observations.
The typical life cycle of a PCAP will be discussed, including the role of synoptic-scale warm and cold air advection, thermally driven flows within and along the edges of the PCAP, diurnal variation of the vertical PCAP structure, the formation of a cloud layer at the cold pool top, and the role of strong pre-frontal winds in the removal of the cold pool. Besides the meteorological processes, their effects on the chemical evolution of a PCAP and on the spatial and temporal variation of PM2.5 concentrations will be addressed.

Practical information

  • General public
  • Free
  • This event is internal


  • EESS - IIE


  • Prof. Michael Lehning and Dr Hendrik Huwald, CRYOS


Mountain Meteorology Cold Air Pools Air Pollution Atmospheric Boundary Layer Meteorological Instrumentation Surface Energy Balance