The influence of local circulations on vertical profiles of NO2 and O3 at semi-rural sites during DISCOVER-AQ campaigns in California, Texas, and Colorado

Monday, 15 December 2014: 3:10 PM
Deborah Claire Stein Zweers1, Kenneth E Pickering2, Richard D Clark3, Andrew John Weinheimer4, Clare Flynn5, Gina Mazzuca5 and Elena Spinei1, (1)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (2)NASA Goddard Space Flight Cent, Greenbelt, MD, United States, (3)Millersville University of Pennsylvania, Millersville, PA, United States, (4)NCAR, Boulder, CO, United States, (5)University of Maryland, College Park, MD, United States
Through use of the Millersville University tethersonde balloon an NO2-sonde, developed at the Royal Netherlands Meteorological Institute (KNMI), profiled the lower boundary layer as part of the larger NASA Earth Venture program funded mission. This campaign known as DISCOVER-AQ stands for ‘Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality’. Recent results from the California, Texas, and Colorado deployments of DISCOVER-AQ highlight the importance of semi-continuous, daytime measurement of the vertical distribution of ozone and NO2 in the lower boundary layer. The balloon profiles, typically from the surface to 500m above ground level, fill an important gap between surface measurements and the lowest extent of aircraft measurements. This near-surface region of the atmosphere is highly variable and local circulation features including land-sea breezes and mountain-valley breezes were observed. These circulations altered local transport patterns and led to changes in the chemical regime at each site. These processes were especially apparent at Smith Point, Texas during an extreme pollution event on 25 September 2013. The extent to which these local circulations influenced diurnal variation and vertical distribution of NO2 and ozone is evaluated and compared for each semi-rural site using wind direction and other meteorological data. NO2-sonde profile data is compared to ground station trace gas analyzers and where available, column and profile measurements from PANDORA spectrometer instruments. These data measured in the segment of the near-surface atmosphere most critical for human health are unique and crucial for validation of satellite columns and atmospheric chemical models.