Canopy level fluxes of 2-methyl-3-buten-2-ol, acetone, and methanol by a portable relaxed eddy accumulation system

Canopy level flux measurements of 2-methyl-3-buten-2-ol (MBO), acetone, and methanol were made over a subalpine forest in the Rocky Mountains in Color ado in the summer of 1999. The measurements were carried out using a portab le relaxed eddy accumulation system that collected samples on adsorbent car tridges. Midday fluxes of acetone were highest at similar to2.5 mg of C m(- 2) h(-1). Methanol and MBO fluxes were similar to1.0 mg of C m(-2) h(-1) ea ch. These fluxes occurred with average daytime high temperatures of only 18 degreesC. Diurnal fluxes of MBO were strongly correlated with light and te mperature. Acetone and methanol did not have simple diurnal patterns. These results indicate that oxygenated volatile organic compounds may make a sig nificant contribution to the flux of reactive carbon to the atmosphere in w estern U.S. pine forests.