Observations of urban NO_x plume dispersion using mobile and satellite DOAS measurements around the megacity of St.Petersburg (Russia)

ABSTRACT

Mobile DOAS (Differential Optical Absorption Spectroscopy) circular measurements of tropospheric nitrogen dioxide (NO₂) were performed on a number of days in 2012 and 2014–2016 around St.Petersburg. These observations figured out an evolution of urban pollution plume, released from the megacity. The HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectories) model was configured to simulate the observed NO₂ dispersion, taking into account the municipal inventory database of urban nitrogen oxides (NO_x = NO+ NO₂) emission. The simulation results were found consistent with the data of mobile measurements, allowing to fit an estimate of integral NO_x emission rate from St.Petersburg (about 60 kt year⁻¹ on the average). Coincident satellite measurements the Aura Ozone Monitoring Instrument (OMI) of tropospheric NO₂ mostly agree with the data of simulation on the days of mobile observations. In general, presented results demonstrate the capabilities of joint interpretation of disparate tropospheric NO₂ data in the vicinity of a megacity.

Acknowledgments

The instrument used for DOAS mobile measurements belongs to the Centre for Geo-Environmental Research and Modelling (GEOMODEL), St.Petersburg State University. The data analysis of this study was partly supported by the Russian Foundation for Basic Research under Grant number 14-05-00897. The numerical model simulation was supported by the Russian Science Foundation under Grant number 14-17-00096. We would like to thank the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) for supplying the OMI tropospheric NO₂ vertical column density data.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Russian Foundation for Basic Research [14-05-00897];Russian Science Foundation [14-17-00096].