Tropospheric ozone seasonal and long-term variability as seen by lidar and surface measurements at the JPL-Table Mountain Facility, California

Abstract

Abstract. A combined surface and tropospheric ozone climatology and interannual variability study was performed for the first time using co-located ozone photometer measurements (2013)(2014)(2015) and tropospheric ozone differential absorption lidar measurements (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) at the Jet Propulsion Laboratory Table Mountain Facility (TMF; elev. 2285 m), in California.The surface time series were investigated both in terms of seasonal and diurnal variability. The observed surface ozone is typical of high-elevation remote sites, with small amplitude of the seasonal and diurnal cycles, and high ozone values, compared to neighboring lower altitude stations representative of urban boundary layer conditions. The ozone mixing ratio ranges from 45 ppbv in the winter morning hours to 65 ppbv in the spring and summer afternoon hours. At the time of the lidar measurements (early night), the seasonal cycle observed at the surface is similar to that observed by lidar between 3.5 and 9 km.Above 9 km, the local tropopause height variation with time and season impacts significantly the ozone lidar observations. The frequent tropopause folds found in the vicinity of TMF (27 % of the time, mostly in winter and spring) produce a dual-peak vertical structure in ozone within the fold layer, characterized by higher-than-average values in the bottom half of the fold (12-14 km), and lower-than-averaged values in the top half of the fold (14-18 km). This structure is consistent with the expected origin of the air parcels within the fold, i.e., mid-latitude stratospheric air folding down below the upper tropospheric sub-tropical air. The influence of the tropopause folds extends down to 5 km, increasing the ozone content in the troposphere. A classification of the air parcels sampled by lidar was made at 1 km intervals between 5 and 14 km altitude, using 12-day backward trajectories (HYSPLIT, Hybrid Single Particle Lagrangian Integrated Trajectory Model). Our classification revealed the influence of the Pacific Ocean, with air parcels of low ozone content (43-60 ppbv below 9 km), and significant influence of the stratosphere leading to ozone values of 57-83 ppbv down to 8-9 km. In summer, enhanced ozone values (76 ppbv at 9 km) were found in air parcels originating from Central America, probably due to the enhanced thunderstorm activity during the North American Monsoon. Influence from Asia was observed throughout the year, with more frequent episodes during spring, associated with ozone values from 53 to 63 ppbv at 9 km.

An Assessment of Ground Level and Free Tropospheric Ozone Over California and Nevada

“…The boundary layer (<3 km) O 3 seasonal cycle is bimodal with peaks in May-June and August-September in AJAX and lidar data sets (Figure 6, bottom), indicative of the competing influences on boundary layer O 3 in the western U.S. The summertime O 3 maximum is generally associated with the peak in photochemical O 3 production, whereas the springtime maximum is attributed to the combination of enhanced stratosphereto-troposphere transport, long-range transport of pollution, and photochemical production (Cooper et al, 2016JD026266 2011Granados-Muñoz & Leblanc, 2016;Lin et al, 2012;Parrish et al, 2013). Variations in O 3 < 3 km observed by AJAX, THD ozonesonde, and lidar can be expected when considering differences in site location, timing of measurements, and variability of data density.…”

A fully autonomous ozone, aerosol and nighttime water vapor lidar: a synergistic approach to profiling the atmosphere in the Canadian oil sands region

“…Water vapor plays a pivotal role in climate change and atmospheric stability by directly influencing many atmospheric processes such as cloud formation (Pruppacher and Klett, 1997) and photochemical atmospheric reactions (Yamamoto et al, 1966;Grant, 1991). Furthermore, tropospheric water vapor is a catalyst to many atmospheric chemical reactions by functioning as a solvent for chemical products of natural and anthropogenic activities (Grant, 1991).…”

Validation of the TOLNet Lidars: The Southern California Ozone Observation Project (SCOOP)

“…Tropospheric ozone is also a short-lived greenhouse gas impacting climate, contributing to the Earth's global warming (IPCC, 2013). Despite significant regulatory efforts and pollution-control programs developed over the past 20 years in the most densely-populated regions of the globe (e.g., Europe, North America and more recently Asia), recent reports of continuing free tropospheric ozone 10 increases, for example in the Western United States (Cooper et al, 2012;Granados-Muñoz and Leblanc, 2016), have triggered the need to enhance our tropospheric ozone observation capabilities. In this context, the North American-based Tropospheric Ozone Lidar Network (TOLNet, https://www-air.larc.nasa.gov/missions/TOLNet/) was recently established to provide high spatio-temporal observations of tropospheric ozone to 1) better understand physical processes driving the ozone budget in various meteorological and environmental conditions, and 2) validate the tropospheric ozone measurements of 15 upcoming space-borne missions such as TEMPO (Tropospheric Emissions: Monitoring of POllution, http://tempo.si.edu) (Zoogman et al, 2014;Johnson et al, 2018) or TROPOMI (TROPOspheric Monitoring Instrument, http://www.tropomi.eu/).…”