Observations of Antarctic Tropospheric Ozone Depletion Events from an Autonomous Ozone Sensor Network

We have developed and deployed a network of low power autonomous ozone photometers at existing Automatic Weather Stations (AWS) in the Ross Island region of Antarctica (see map of station locations). These ozone augmented weather stations have been in operation since February 2012. The remote locations of the AWS sites and the use of renewable non-polluting energy sources, is providing ozone observations that are free of anthropogenic influence and hence more representative of the broader distribution in the region. This data set is invaluable for studying the natural background processes that control tropospheric ozone, without the influence of transported pollution and local pollution sources that have muddied the interpretation of other polar ozone measurements. Furthermore, this network approach to ozone monitoring has important advantages over a single station both for establishing a record of surface level ozone distributions and for the study of specific phenomena such as ozone depletion events. The combination of the AWS and ozone sensor networks provides significantly more information than obtainable from any single measurement. Through the application of trajectory modeling based on the AWS meteorological data fields, the source and evolution of ozone-depleted air masses can be inferred. The field sites for this network were specifically chosen to maximize our ability to diagnose the source of ozone depleted air masses, to observe the rate of ozone depletion as air masses pass multiple stations and to diagnose the relationship between boundary layer dynamics and the severity of ozone depletion. We will present the preliminary observations from the first full season of ozone measurements from the network, and compare these with single point measurements of ozone depletion events and related chemistry from previous Austral Springs. These previous measurement campaigns have demonstrated a clear meteorological signature that accompanies the majority of ozone depletion events. Further more, there is a robust correlation between these previously observed ozone depletion events, and changes in the size distribution and composition of sub micron aerosols. These meteorological signature and chemical correlations will be further examined using the data collected from the Ozone Sensor Network during the Austral spring of 2012.