UC Irvine

Dimethyl sulfide (DMS) and sulfur dioxide (SO2) mixing ratios were measured in the boundary layer on Oahu, Hawaii in April and May 2000. Average DMS and SO2 levels were 22 ± 7 (n = 488) pmol/mol and 23 ± 7 (n = 471) pmol/mol respectively. Anti-correlated DMS and SO2 diurnal cycles, consistent with DMS + OH oxidation were observed on most days. Photochemical box model simulations suggest that the yield of SO2 and total SO2 sink are ∼85% and ∼2 × 104 molec cm-3 s-1 respectively. On several days the rate of decrease in DMS and increase in SO2 levels in the early morning were larger that predicted by the model. Dynamical and chemical causes for the anomalous early morning data are explored. © Springer Science+Business Media, Inc. 2005.