The investigation of possible stratospheric origin of ozone presence at the surface at night, using HYSPLIT trajectory analysis

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Kosin, Moses Ejiroghene
Reynolds, Nathaniel

IMPORTANCE: On August 2, 2012, high tropospheric ozone levels, above the EPA limit of 75 parts per billion by mass, were forecast for Wichita, Kansas. Trajectories for ozone transport were examined using two software packages: McIDAS and HYSPLIT. The source of the rise of ozone concentration was examined, namely whether it came from the stratosphere or was a buildup from the ground level. Evidence of stratosphere ozone was lacking. OBJECTIVE: The reason for this research is to investigate the source of high concentrations of ozone in the troposphere. One possibility is the entrance of stratospheric ozone via tropopause folding. Another possible source of high ozone concentration comes from photochemistry in the troposphere, possibly around Wichita or upstream of Wichita. However, the photochemistry details are not part of this study. Instead, the study concerns itself with transportation of ozone pollution to Wichita of either tropospheric ozone produced elsewhere or ozone precursors. METHODS: We use the McIDAS software to analyze the data we collected from the NCAR datasets and use the information to analyze the presence of stratospheric ozone and the ozone concentration in Wichita due to the impact of tropopause folding. Also, we applied the HYSPLIT model to investigate where the polluted air was. The map area is attempting to describe the source and movement of ozone, impacting human health. Therefore, the HYSPLIT trajectory analyzes the ozone movement from August 2, 2012, and August 4, 2012, to determine the wind direction. RESULT: During the period, the NCAR (National Center for Atmospheric Research) dataset was collected, and the ozone mixing ratio at 500 hPa and 850 hPa was run. The 500 hPa map and 850 hPa* map in figure 3 and figure 4, respectively, show the ozone values that are relatively high across the same region. The NCAR data result at 850 hPa* and 500 hPa agreed with the forecast of August 2, 2012, that the tropospheric ozone concentration was high. However, the stratosphere ozone cannot be established during this day because the HYSPLIT trajectory model suggested no wind migrating from the Rocky Mountains to Wichita, Kansas. The investigation reviewed that the data from the Cfsrr in the Cfsr (Climate Forecast System Reanalysis) was the framework for this study. It indicates the increased ozone concentration in the troposphere and shows that ozone expels from the stratosphere to the troposphere cannot be established. The 3-D grid model is used to analyze the data, and the color indicates the increase of ozone. Furthermore, the tongue-like structure suggests the presence of tropopause presence in the Rocky Mountains. CONCLUSIONS: There was no stratospheric ozone because the wind direction was not coming from the Rocky Mountains; instead, we saw the trajectory coming from Texas and local wind-generated within Kansas, Oklahoma, Arkansas, and Missouri. However, that part of the ozone transported from Texas, Arkansas, Missouri, and Oklahoma might have escalated the ozone concentration above 75ppb (part per billion).

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Thesis (M.S.)-- Wichita State University, College of Liberal Arts and Sciences, Dept of Geology, Earth, Environmental and Physical Sciences Program