| Popis: |
Baton Rouge, Louisiana, is one of the metropolitan areas in the United States that currently does not meet the national ambient air quality standard for tropospheric ozone. In addition to petrochemical and other industrial activities, the climatological characteristics of the area meaningfully impact the development of tropospheric ozone. This research study attempts to assess factors contributing to elevated concentrations of tropospheric ozone. Hourly observations of surface ozone concentrations were analyzed for eleven ambient air quality stations in the Baton Rouge metropolitan nonattainment zone (BRNAZ). Data covering a 15-year period, January 1993 Dec 2007, was characterized according to varying temporal scales: annually, seasonally, monthly, and daily. Utilizing an environment-to-circulation approach, surface ozone concentrations were related to broad-scale steering circulation patterns. The combination of principal components analysis and k-means cluster analysis enabled the 700 hPa geopotential height fields for 792 days which experienced elevated ozone (70 ppb) to be categorized into nine clusters, representing the major modes of synoptic variability related to surface ozone concentrations in the BRNAZ. Overall ozone forcing patterns were broadly determined to be synoptic subsidence, Gulf High, and non-meteorological related. The third major component of this study involved a series of ozonesonde launches in the spring of 2006. The primary purpose of the launches was to investigate the diurnal variation in the vertical distribution of tropospheric ozone within the BRNAZ. The data collected indicated subsidence, radiational cooling, frontal passage, advection, and turbulent mixing influenced the development of tropospheric ozone. |
