The Effect of Ozonopause Placement on Tropospheric Ozone Budgets: An Analysis of Ozonesonde Profiles From Selected IONS-06 Sites

Open Access
Dougherty, Kerry Meaghan
Graduate Program:
Master of Science
Document Type:
Master Thesis
Date of Defense:
April 10, 2008
Committee Members:
  • Anne Mee Thompson, Thesis Advisor
  • ozonopause
  • tropospheric ozone
  • ozonesonde
Identifying the tropopause is a significant challenge because it can be defined thermally, dynamically, or chemically. This study calculates ozonopauses using five methods that are each based on an ozone concentration cutoff, a best fit line, or an ozone gradient. The data set includes spring and summer ozonesonde launches from the IONS-06 campaigns in Narragansett, Rhode Island; Kelowna, British Columbia; and Houston, Texas. Variations in the ozonopause placements are dependent on season and site. On average, the five methods match most closely for the spring launches over Kelowna; the five methods differ the most for summer launches over Houston. The five ozonopauses for each day yield five estimates of the total tropospheric ozone column (TTOC). Tropospheric ozone budgets are calculated by dividing each TTOC into four categories: boundary layer ozone, regional convection and lightning generated ozone, stratospherically injected ozone, and aged or recently advected ozone. The five budgets from each day are compared to assess the effect of ozonopause placement on tropospheric ozone budgets. Seasonal averages of the ozone budgets for each site indicate that the relative contributions of each term change by less than 5% of the TTOC. Daily comparisons can lead to higher differences on days for which there are large variations in ozonopause placements.