Measurements of OH, H sub(2)SO sub(4), and MSA during Tropospheric Ozone Production About the Spring Equinox (TOPSE)

Data from OH, H sub(2)SO sub(4), and MSA measurements performed during Tropospheric Ozone Production About the Spring Equinox (TOPSE) are presented. Model simulations of OH results made at solar zenith angles of 60 degree or less showed a tendency of the model to overestimate OH concentrations. This overestimation was a factor of 1.7 at the lower latitudes (57 degree N) the model tended toward agreement and ultimately an underestimation of OH concentrations by a factor of 0.7. Comparisons of measurements and model showed the model underestimates OH concentrations at solar zenith angles greater than 70 degree . The results of the present study are discussed in the context of previous studies. Possible model discrepancies are discussed. Measurements of H sub(2)SO sub(4) showed the highest concentrations at the lowest altitudes (