Transport of substantial stratospheric ozone to the surface by a dying typhoon and shallow convection
Open Access
- 24 June 2022
- journal article
- research article
- Published by Copernicus GmbH in Atmospheric Chemistry and Physics
- Vol. 22 (12), 8221-8240
- https://doi.org/10.5194/acp-22-8221-2022
Abstract
Stratospheric ozone transported to the troposphere is estimated to account for 5 %–15 % of the tropospheric ozone sources. However, the chances of intruded stratospheric ozone reaching the surface are low. Here, we report an event of a strong surface ozone surge of stratospheric origin in the North China Plain (NCP, 34–40∘ N, 114–121∘ E) during the night of 31 July 2021. The hourly measurements reveal surface ozone concentrations of up to 80–90 ppbv at several cities over the NCP from 23:00 LST (Local Standard time, = UTC +8 h) on 31 July to 06:00 LST on 1 August 2021. The ozone enhancement was 40–50 ppbv higher than the corresponding monthly mean. A high-frequency surface measurement indicates that this ozone surge occurred abruptly, with an increase reaching 40–50 ppbv within 10 min. A concurrent decline in surface carbon monoxide (CO) concentrations suggests that this surface ozone surge might have resulted from the downward transport of a stratospheric ozone-rich and CO-poor air mass. This is further confirmed by the vertical evolutions of humidity and ozone profiles based on radiosonde and satellite data respectively. Such an event of stratospheric impact on surface ozone is rarely documented in view of its magnitude, coverage, and duration. We find that this surface ozone surge was induced by a combined effect of dying Typhoon In-fa and shallow local mesoscale convective systems (MCSs) that facilitated transport of stratospheric ozone to the surface. This finding is based on analysis of meteorological reanalysis and radiosonde data, combined with high-resolution Weather Research and Forecasting (WRF) simulation and backward trajectory analysis using the FLEXible PARTicle (FLEXPART) particle dispersion model. Although Typhoon In-fa on the synoptic scale was at its dissipation stage when it passed through the NCP, it could still bring down a stratospheric dry and ozone-rich air mass. As a result, the stratospheric air mass descended to the middle-to-low troposphere over the NCP before the MCSs formed. With the pre-existing stratospheric air mass, the convective downdrafts of the MCSs facilitated the final descent of stratospheric air mass to the surface. Significant surface ozone enhancement occurred in the convective downdraft regions during the development and propagation of the MCSs. This study underscores the substantial roles of weak convection in transporting stratospheric ozone to the lower troposphere and even to the surface, which has important implications for air quality and climate change.Keywords
Funding Information
- National Natural Science Foundation of China (42105079)
This publication has 73 references indexed in Scilit:
- Changes in surface ozone levels due to convective downdrafts over the Bay of BengalGeophysical Research Letters, 2006
- Determining the tropopause height from gridded dataGeophysical Research Letters, 2003
- Carbon monoxide, regional‐scale transport, and biomass burning in tropical continental Southeast Asia: Observations in rural ThailandJournal of Geophysical Research: Atmospheres, 2003
- Stratosphere‐troposphere exchange: A review, and what we have learned from STACCATOJournal of Geophysical Research: Atmospheres, 2003
- Characteristics of biomass burning emission sources, transport, and chemical speciation in enhanced springtime tropospheric ozone profile over Hong KongJournal of Geophysical Research: Atmospheres, 2003
- Transport of ozone to the surface by convective downdrafts at nightJournal of Geophysical Research: Atmospheres, 2002
- Tropical cyclone Marlene and stratosphere‐troposphere exchangePublished by American Geophysical Union (AGU) ,1999
- Stratosphere‐troposphere exchange in a midlatitude mesoscale convective complex: 2. Numerical simulationsPublished by American Geophysical Union (AGU) ,1996
- Stratosphere‐troposphere exchange in a midlatitude mesoscale convective complex: 1. ObservationsJournal of Geophysical Research: Atmospheres, 1996
- Stratosphere‐troposphere exchangeReviews of Geophysics, 1995