A Model Analysis of Anthropogenic Influences on Ozone and Related Species: The Interaction of Transport and Chemistry

226 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2002.Significant seasonal variations in the concentrations of several trace gases were observed in the southern tropical Pacific during the PEM-TROPICS-A (PT-A) and PEM-TROPICS-B (PT-B) campaigns. In the second part of this thesis, a 3D CTM, MOZART, is used to investigate the ozone budget and identify its controlling factors over this region. The model reproduced the main features of the observed seasonal variation in ozone and CO. The ozone burden during the PT-A was larger due to the transport of ozone into the central Pacific middle-troposphere from the west, whereas a net outflow of ozone from this region to the east resulted in a reduction of ozone burden during the PT-B period. Transport of ozone from the Northern Hemisphere into this region was found to be much larger during the PT-B period compared to the PT-A period. Results from MOZART were also used to generate correlations in the ratios of non-methane hydrocarbons and the variability in their mixing ratio distributions as a function of their local lifetimes. Comparisons between this correlation with experimental observations enabled us to identify a source-receptor relationship over the southern tropical Pacific region.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD