Vertical Profiles of Ozone Concentrations in the Lower Troposphere Downwind of New York City During LISTOS 2018–2019
While surface concentrations of ozone are routinely monitored, ozone aloft is infrequently measured, but critical for a full understanding of ozone production and transport. In this study, twenty‐six balloon‐borne ozonesondes were launched near the north shore of central Long Island in the summers o...
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| Published in: | Journal of geophysical research. Atmospheres Vol. 126; no. 23 |
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| Main Authors: | , , , , , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Washington
Blackwell Publishing Ltd
16-12-2021
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | While surface concentrations of ozone are routinely monitored, ozone aloft is infrequently measured, but critical for a full understanding of ozone production and transport. In this study, twenty‐six balloon‐borne ozonesondes were launched near the north shore of central Long Island in the summers of 2018 and 2019 as part of the Long Island Sound Tropospheric Ozone Study (LISTOS). The observed vertical ozone profiles are presented and analyzed with additional data sources and modeling tools, including lidar wind profiles from the New York State Mesonet, back trajectories based on 3 km resolution high‐resolution rapid refresh model data, and surface data, aircraft observations, sonde, and ozone lidar measurements from other LISTOS participants. Special attention is given to the region of interest for ozone pollution in the lower troposphere, from the surface to 2 km altitude. Cases analyzed in detail illustrate events with high ozone levels observed in the lower troposphere, often with pronounced vertical structure in the profile. Specifically, easily discernible layers are identified with ozone excursions of up to 40 ppb over short vertical distances. Analysis indicates that synoptic and local meteorological processes can combine to generate the observed vertical profiles. Hot, sunny days with high‐pressure systems are accompanied by high precursor emissions due to increased power demands, plentiful radiation for photochemistry, and stagnation of synoptic winds. Under these conditions, meso‐ and smaller‐scale flows like low‐level jets and sea/bay/land breeze circulations may dominate synoptic flow to produce shearing and the complex vertical layered structure observed.
Plain Language Summary
Ground‐level ozone pollution is a persistent threat to public health. Ozone is not directly emitted, but forms when emitted pollutants are exposed to sunlight. Winds that would normally dissipate ozone may be disrupted by local weather features produced in coastal regions where land and water meet. Understanding the meteorology behind high ozone events is important to forecasting unhealthy air quality days accurately. Twenty‐six ozone sensors were launched via balloon from Long Island (LI) in 2018 and 2019 as part of the Long Island Sound Tropospheric Ozone Study. These sensors provide detailed vertical measurements of ozone and weather useful for understanding how ozone is formed and transported. Through five case studies, we described the impacts of small‐scale, local circulations on ground‐level ozone. Ozone buildup comes from large‐scale transport, low‐level jets, stagnation events when the winds were very light for a sustained period of time, and sea breeze circulations. These situations occur on both the Sound and Atlantic sides of LI, bringing in pollutants from the water onto land. This article illustrates the complex meteorology behind high ozone days in coastal areas near cities.
Key Points
Vertical ozone profiles below 2 km can exhibit layering with little connection to surface concentrations
Sea breeze circulation during stagnation near the land‐water interface often induces layering
Vertical shearing as a result of low‐level jets or sea breeze circulation provides mechanisms for the formation of layers |
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| ISSN: | 2169-897X 2169-8996 |
| DOI: | 10.1029/2021JD035108 |