Author: Samantha Danielle Caputi

Publisher:

Published: 2020

Total Pages: 0

ISBN-13:

The San Joaquin Valley has a notorious ozone violation problem that has persisted despite other areas in California trending toward cleaner air at a faster rate in recent decades. Here we synthesize the various synoptic, mesoscale, and microscale meteorological factors that contribute to this problem. In particular, data from the California Baseline Ozone Transport Study (CABOTS) field campaign in the summer of 2016 are analyzed, which include 170 hours of aircraft data, and these aircraft deployments are looked at in the context of background synoptic-scale meteorological conditions. We lastly highlight the importance of measuring synoptic-scale subsidence in mountain-valley systems such as the San Joaquin Valley where air pollution is an issue, assess our current ability to accomplish this, and propose new methods for future research in this domain. Some key findings from these analyses include: 1) Nighttime mesoscale features in the Southern San Joaquin Valley, mainly the low level jet and Fresno Eddy, can either recirculate or deplete ozone from the previous day, and which of these two processes dominate on any given night is determined by the low level jet strength; 2) It is extremely important to track the chemical fate of the Nitrate radical at night as this can have a large effect on the ozone budget; 3) A 3-layer model of the atmosphere is proposed, where a buffer layer exists between the daytime boundary layer and free troposphere above, and the entrainment processes at the top of the boundary layer are important to track as pollutants from the previous day can be injected into the buffer layer by the mountain-valley circulation; 4) A low-cost method of estimating turbulence (specifically the convective velocity scale, turbulent kinetic energy, and eddy dissipation) from aircraft data without a gust probe is developed; 5) The newly developed Micro-Doppler lidar that was used during CABOTS shows promising first results in its ability to measure fair-weather vertical velocities in the lower atmosphere.