First quasi-Lagrangian in situ measurements of Antarctic Polar springtime ozone: observed ozone loss rates from the Concordiasi long-duration balloon campaign

R Schofield,A Hertzog,M Rex,L M Avallone,L E Kalnajs,I Wohltmann

doi:10.5194/acp-15-2463-2015

Abstract

Abstract. We present ozone measurements made using state-of-the-art ultraviolet photometers onboard three long-duration stratospheric balloons launched as part of the Concordiasi campaign in austral spring 2010. Ozone loss rates calculated by matching air parcels sampled at different times and places during the polar spring are in agreement with rates previously derived from ozonesonde measurements, for the vortex average, ranging between 2 and 7 ppbv per sunlit hour or between 25 and 110 ppbv per day. However, the geographical coverage of these long-duration stratospheric balloon platforms provides new insights into the temporal and spatial patterns of ozone loss over Antarctica. Very large ozone loss rates of up to 230 ppbv per day (16 ppbv per sunlit hour) are observed for air masses that are downwind of the Antarctic Peninsula and/or over the East Antarctic region. The ozone loss rate maximum downstream of the Antarctic Peninsula region is consistent with high PSC occurrence from CALIPSO and large ClO abundances from MLS satellite observations for 12–22 September 2010, and with a chemical box model simulation using JPL 2011 kinetics with full chlorine activation.

Highlights

Twenty-six years after the signing of the Montreal protocol, widely considered the most successful international environmental policy of our time, there is evidence that stratospheric chlorine – the primary anthropogenic contributor to stratospheric ozone loss – is returning to pre-human-influence levels
This paper presents for the first time ozone loss rates measured in situ onboard quasi-Lagrangian balloons and is organised as follows
Klekociuk et al (2011) found that there was very little dynamical disturbance of the polar vortex after September; the rates observed by Concordiasi were not influenced by a premature break-up

Summary

Introduction

Twenty-six years after the signing of the Montreal protocol, widely considered the most successful international environmental policy of our time, there is evidence that stratospheric chlorine – the primary anthropogenic contributor to stratospheric ozone loss – is returning to pre-human-influence levels. The modelling section details the match analysis and ozone loss rates derived for the balloon flights. Ozone loss has been observed in situ over long periods of time by specially designed ultraviolet photometers (Kalnajs and Avallone, 2010) flown on long-duration balloons launched as part of the Concordiasi campaign (Rabier et al, 2013) out of McMurdo Station, Antarctica, in austral spring of 2010. JPL 2011 (Sander et al, 2011) chemistry was used to drive a chemical box model (Wohltmann and Rex, 2008) along one representative match trajectory for each 10 day period for each balloon This provided an indication of the expected ozone loss rates assuming full chlorine activation (ClOx = Cly).

Results and discussion

12–22 Sep: 2010

Conclusions