Analysis of near-surface ozone variations in Terra Nova Bay, Antarctica

Ozone concentration measurements were made during December from 2001-2005 to quantify the contributions of different processes to near-surface ozone concentrations (03) in Terra Nova Bay, Antarctica. The average 03 concentration was 20.3 ppbv. On days characterized by high solar radiation fluxes (HSR), significantly higher concentrations Of 03 (21.3 ppbv) were recorded compared to days with low solar radiation fluxes (LSR days, 16.8 ppbv). High 03 Concentrations could be related to strong winds from SW-NW. Three-dimensional back-trajectories show that air from the interior of the continent could affect 03 at Terra Nova Bay. Moreover, during HSR days, high 03 concentrations were also recorded in connection with weak circulation, suggesting that emissions from the Italian base (located 2 km north) could also represent a significant source Of O(3). To clarify the role of local pollution in Terra Nova Bay, 03 values were also calculated using the photochemical steady state (PSS) approximation under clear sky and cloudy conditions.