Daily Evolution of Boundary Layer Properties based on NASA DISCOVER-AQ Airborne Profiles over the California San Joaquin Valley

The DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) mission conducted its second field deployment in the California San Joaquin Valley region during January and February 2013. The overarching goal is to better understand how remotely-sensed column measurements can be used to diagnose near-surface air quality. To achieve this objective, the DISCOVER-AQ sampling strategy requires extensive probing of the vertical structure of the lower troposphere as it relates to both trace gases and aerosols. This strategy was implemented by using the NASA P-3B aircraft to spiral from 0.3 to ~3 km over 6 air quality monitoring ground sites at three different times of the day (mid-morning, midday, and mid-afternoon local time). In addition, missed approach maneuvers were performed at 7 airports along the flight path, which provided profile data from ~25 m up through the 0.3 km bottom limit of the spirals. A total of 170 spirals and 157 missed approaches were flown, which generated detailed vertical distributions for a large variety of trace gases, aerosol properties, and meteorological variables. Using this dataset, a detailed assessment of the daily evolution of boundary layer properties, including boundary layer height and degree of vertical gradient of atmospheric properties and composition, will be presented. Additionally, the local contributions to horizontal inhomogeneities will be evaluated.