Two case studies on the interaction of large-scale transport, mesoscale photochemistry, and boundary-layer processes on the lower tropospheric ozone dynamics in early spring | Health & Environmental Research Online (HERO)

HERO ID

1603788

Reference Type

Journal Article

Title

Two case studies on the interaction of large-scale transport, mesoscale photochemistry, and boundary-layer processes on the lower tropospheric ozone dynamics in early spring

Author(s)

Bronnimann, S; Siegrist, FC; Eugster, W; Cattin, R; Sidle, C; Hirschberg, MM; Schneiter, D; Perego, S; Wanner, H

Year

2001

Is Peer Reviewed?

Yes

Journal

Annales Geophysicae
ISSN: 0992-7689
EISSN: 1432-0576

Volume

19

Issue

4

Page Numbers

469-486

Web of Science Id

WOS:000169900900006

Abstract

The vertical distribution of ozone in the lower troposphere
over the Swiss Plateau is investigated in detail for two episodes in early spring (February 1998
and March 1999). Profile measurements of boundary-layer ozone performed during two field
campaigns with a tethered balloon sounding system and a kite are investigated using regular
aerological and ozone soundings from a nearby site, measurements from monitoring stations at
various altitudes, backward trajectories, and synoptic analyses of meteorological fields.
Additionally, the effect of in situ photochemistry was estimated for one of the episodes
employing the Metphomod Eulerian photochemical model. Although the meteorological situations were
completely different, both cases had elevated layers with high ozone concentrations, which is not
untypical for late winter and early spring. In the February episode, the highest ozone
concentrations of 55 to 60 ppb, which were found at around 1100 m asl, were partly advected from
Southern France, but a considerable contribution of in situ photochemistry is also predicted by
the model. Below that elevation, the local chemical sinks and surface deposition probably
overcompensated chemical production, and the vertical ozone distribution was governed by
boundary-layer dynamics. In the March episode, the results suggest that ozone-rich air parcels,
probably of stratospheric or upper tropospheric origin, were advected aloft the boundary layer on
the Swiss Plateau.

Keywords

atmospheric composition and structure (pollution urban and regional troposphere; composition and chemistry); meteorology and atmospheric dynamics (mesoscale meteorology)