No abstract

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 Colorado in the summer of 1999. The measurements were carried out using a portable relaxed eddy accumulation system that collected samples on adsorbent cartridges. Midday fluxes of acetone were highest at ∼2.5 mg of C m -2 h -1 . Methanol and MBO fluxes were ∼1.0 mg of C m -2 h -1 each. These fluxes occurred with average daytime high temperatures of only 18°C. Diurnal fluxes of MBO were strongly correlated with light and temperature. Acetone and methanol did not have simple diurnal patterns. These results indicate that oxygenated volatile organic compounds may make a significant contribution to the flux of reactive carbon to the atmosphere in western U.S. pine forests.

Abstract. Isoprene emissions from oak trees in the eastern USA play an important role in tropospheric ozone pollution. Oak trees (Quercus) emit an order of magnitude more isoprene than most other emitting tree species, and are by far the largest source of biogenic isoprene in the eastern US. We used Landsat TM data to measure oak tree abundance near Oak Ridge, Tennessee, to estimate uxes of isoprene. The Landsat classi cation was performed using multi-date data, supervised classi cation techniques, and an iterative approach. Training sites were selected based on transect data, and ten vegetation classes were mapped. A supervised classi cation algorithm called the Spectral Angle Mapper was used to classify the data. Empirical vegetation emission data were used to estimate the isoprene ux from each of the vegetation classes. The resultant isoprene ux maps were compared with concentrations measured in the eld, and a good correspondence was observed. We also compare the Landsat classi cation with three other landcover schemes including the USGS's Global Landcover Classi cation, which is based on AVHRR data. Results from these landcover classi cations are used as input for models that predict tropospheric ozone production and are used to investigate ozone control strategies.