Abstract
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).
Highlights
Ozone (O3) is a natural atmospheric component that is found in both the stratosphere and the troposphere and plays a major role in the atmospheric environment through radiative and chemical processes
The results are shown in Table 2; it can be concluded that the slopes of the linear correction curve were 0.99936 and 1.02520, and the intercepts were 0.53861 and 0.85220l, which fulfilled the requirements of HJ 590-2010 and USEPA
Gridded meteorological data for backward trajectories in the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model were obtained from the Global Data Assimilation System (GDAS1) operated by National Oceanic and Atmospheric Administration (NOAA) with 1◦ ×1◦ horizontal resolution and 23 vertical levels, from 1000 to 20 hPa
Summary
Ozone (O3) is a natural atmospheric component that is found in both the stratosphere and the troposphere and plays a major role in the atmospheric environment through radiative and chemical processes. Many studies have observed summer episodes of “O3 enhancement events” (OEEs) in the Antarctic interior (e.g., Crawford et al, 2001; Legrand et al, 2009; Cristofanelli et al, 2018), and they have attributed this phenomenon to the NOx emissions from the snowpack and subsequent photochemical O3 production (for example, Jones et al, 2000). This may provide an input source for the entire Antarctic region (for example, Legrand et al, 2016; Bauguitte et al, 2011). This study broadens the understanding of the spatial and temporal variations in the near-surface O3 concentration and transport processes that impact tropospheric O3 over high plateaus
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