Measurements and Modeling of Isoprene Fluxes in the Program for Research on Oxidants: Photochemistry, Emissions, and Transport (PROPHET) 2000-01

Washington State University, Pullman WA

Investigators

Abstract

In most rural areas, plant emissions of isoprene are the dominant source of reactive hydrocarbons. During the past three summers, we have made flux measurements of isoprene over a mixed northern hardwood forest in northern Michigan as part of the Program for Research on Oxidants: Photochemistry, Emissions, and Transport (PROPHET), located at the University of Michigan Biological Station (UMBS). We have discovered a very strong correlation between sensible heat flux and isoprene flux on a daily basis. If the basis for this correlation can be understood, using heat flux as a model parameter for isoprene emissions would represent a significant advance in our ability to model isoprene fluxes. Heat flux is an inherent surface layer parameter predicted in all mesoscale meteorological models and global circulation models. Thus, it is readily available for modeling isoprene on regional and global scales. In this project we will continue our isoprene flux measurements at the PROPHET/Ameriflux site during the next two growing seasons. We will employ a fast isoprene analyzer along with fast CO2, water vapor, and temperature sensors to obtain continuous flux measurements throughout the growing season.