Abstract. Dome A, the summit of the East Antarctic Ice Sheet, is an area
challenging to access and is one of the harshest environments on Earth. Up
until recently, long-term automated observations from Dome A (DA) were only
possible with very low power instruments such as a basic meteorological
station. To evaluate the characteristics of near-surface O3, continuous
observations were carried out in 2016. Together with observations at the
Amundsen–Scott Station (South Pole – SP) and Zhongshan Station (ZS, on the
southeast coast of Prydz Bay), the seasonal and diurnal O3
variabilities were investigated. The results showed different patterns
between coastal and inland Antarctic areas that were characterized by high
concentrations in cold seasons and at night. The annual mean values at the
three stations (DA, SP and ZS) were 29.2±7.5, 29.9±5.0 and 24.1±5.8 ppb, respectively. We investigated the effect of
specific atmospheric processes on near-surface summer O3 variability,
when O3 enhancement events (OEEs) are systematically observed at DA
(average monthly frequency peaking at up to 64.5 % in December). As deduced
by a statistical selection methodology, these O3 enhancement events
(OEEs) are affected by significant interannual variability, both in their
average O3 values and in their frequency. To explain part of this
variability, we analyzed the OEEs as a function of specific atmospheric
processes: (i) the role of synoptic-scale air mass transport over the
Antarctic Plateau was explored using the Lagrangian back-trajectory analysis Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) method,
and (ii) the occurrence of “deep” stratospheric intrusion events was
investigated using the Lagrangian tool STEFLUX. The specific atmospheric
processes, including synoptic-scale air mass transport, were analyzed by the
HYSPLIT back-trajectory analysis and the potential source contribution
function (PSCF) model. Short-range transport accounted for the O3
enhancement events (OEEs) during summer at DA, rather than efficient local
production, which is consistent with previous studies of inland Antarctica.
Moreover, the identification of recent (i.e., 4 d old) stratospheric-intrusion events by STEFLUX suggested that deep events only had a minor
influence (up to 1.1 % of the period, in August) on deep events
during the variability in near-surface summer O3 at DA. The deep
events during the polar night were significantly higher than those during
the polar day. This work provides unique data on ozone variation at DA and
expands our knowledge of such events in Antarctica. Data are available at
https://doi.org/10.5281/zenodo.3923517 (Ding and Tian, 2020).
Patterns and source analysis for atmospheric mercury at Auchencorth Moss, Scotland
