ANYL Sem Abstracts

This page contains the abstracts for upcoming and past Analytical & Environmental Chemistry Seminars at CU. Please post newer seminars at the top, but do not erase the abstracts from old seminars.

THURSDAY, September 10, 2009

4:00 p.m. CIRES Auditorium (note change of location) University of Colorado, Boulder

What controls the diurnal variability of carbon dioxide and reactive species?

Jordi Vilà-Guerau de Arellano Meteorology and Air Quality Section Wageningen University (The Netherlands) e-mail: jordi.vila@wur.nl http://www.met.wau.nl/medewerkers/vila/index.html

Abstract

We examine the main physical and chemical processes that determine the diurnal variability of atmospheric compounds in the boundary layer. In addition to surface processes, turbulent mixing and reactivity, we put special emphasis on investigating the role of the exchange of heat, water and chemical species between the free troposphere and the atmospheric boundary layer, namely the entrainment process. This process enhances the dilution of compounds and introduces free tropospheric air masses with different characteristics into the atmospheric boundary layer.

In the seminar, I will discuss several cases where entrainment plays a major role in the evolution of atmospheric compounds. By analyzing observational evidence or performing numerical experiments by the large eddy simulation technique and a conceptual (mixed-layer theory) model, we are able to find the contribution of entrainment to the diurnal variability of carbon dioxide or isoprene. Particular emphasis is placed on the need to maintain a balance in dynamic processes and the specific characteristic of each atmospheric compound.