Tracking Potential Sources of Peak Ozone Concentrations in the Arabian Gulf Region



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In August 2013, the Qatar Environment and Energy Research Institute (QEERI), part of Qatar Foundation, was the first to launch weather balloons with ozonesondes in the Middle East region. The data from the initial 20 launches consistently show changes in meteorological parameters at about 5 kilometers above the surface, including temperature inversions, corresponding change in potential temperatures, a dramatic drop in relative humidity, and significant wind shear. These changes are typically associated with a large scale subtropical subsidence layer in accordance with previous aircraft studies in this region. Below the inversion layer, the ozone follows typical patterns for lower tropospheric measurements, starting higher near the surface at about 60ppbv and gradually decreasing to 40ppbv with increasing altitude. However, above the subsidence inversion, ozone concentrations begin to increase from 40ppbv to a peak of 100ppbv at 7 or 8 kilometers, then decreasing again to 40ppbv just before reaching the stratosphere. The focus of this research is to identify the sources of higher ozone concentrations in the 6-12 km altitude range above the subsidence inversion in the month of August. The spatial coordinates of the ozonesondes at 6, 9, and 12km were obtained through the use of Global Positioning System (GPS) data acquired by the attached radiosonde, and HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) back trajectories using these coordinates as a starting point were run to trace the origins of the air mass up to 3 days prior. World Wide Lightning Location Network (WWLLN) lightning data for the northern hemisphere in August and National Oceanic and Atmospheric Administration (NOAA) weather analysis charts of the region at the surface, 500 and 200hPa levels were also evaluated for meteorological conditions such as high or low pressure systems, monsoon, or jet streaks that may have impacted the long-range transport of ozone.



Ozone, Middle East, Qatar, Air quality, Troposphere