Open AccessMeasurements of OH, H 2 SO 4 , and MSA during Tropospheric Ozone Production About the Spring Equinox (TOPSE)
Author(s) -
Mauldin R. L.,
Cantrell C. A.,
Zondlo M. A.,
Kosciuch E.,
Ridley B. A.,
Weber R.,
Eisele F. E.
Publication year - 2003
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002jd002295
Subject(s) - equinox , atmospheric sciences , context (archaeology) , ozone , zenith , troposphere , latitude , solar zenith angle , environmental science , meteorology , chemistry , physics , geology , paleontology , astronomy , optics
Data from OH, H 2 SO 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° 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°N) of the study. At higher latitudes (>57°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°. The results of the present study are discussed in the context of previous studies. Possible model discrepancies are discussed. Measurements of H 2 SO 4 showed the highest concentrations at the lowest altitudes (<2000 m) and the lowest latitudes of the study. Larger H 2 SO 4 concentrations observed at higher latitudes were accompanied at times by particle nucleation as indicated by the presence of UCN (ultra‐fine condensation nuclei) with diameters of 3–4 nm. Concentrations of MSA were generally low with typical values of <2 × 10 5 molecule cm −3 . High concentrations (>10 7 molecule cm −3 ) were found in layers and were accompanied by other compounds such as NO x and NO y indicating MSA may also have an industrial source.