Davis ozonesonde measurements

Brief description

The Australian Antarctic Division (AAD) in collaboration with the Chinese Academy of Meteorological Science (CAMS) and the Australian Bureau of Meteorology (BoM) operates a program of regular ozonesonde measurements at Davis, Antarctica. An ozonesonde is a balloon-borne instrument which uses a chemical cell as a transducer to measure ozone concentration a function of height. The measurement technique provides a convenient, accurate and cost-effective means profiling atmospheric ozone. At Davis, the measurements are ongoing since early 2003, and are made using Science Pump Corporation type ECC-6A ozonesondes that are flown on 1200 gram meteorological balloons. The desired measurement frequency is weekly throughout the year, although limitations in materials has at times meant that only one flight per month has been possible. During each flight, ozone concentration and standard parameters from a Vaisala RS-92 radiosonde (including pressure, temperature and humidity as a function of location) are obtained. The cathode solution (3.0cc) consists of 1% potassium iodide (KI) w/vol with potassium bromide (KBr) and buffers. The anode solution (1.5cc) is saturated KI solution. The solutions are made using 10g of KI, 25g of KBr, and added buffers, per litre of water. Data holdings in the AADC consist of ASCII text files produced by BoM the World Ozone and Ultraviolet Radiation Data Centre (WOUDC). The WOUDC can also be accessed externally at http://woudc.org/data/explore.php by selecting 'OzoneSonde' under 'Dataset' and 'Davis (450)' under 'Station'. The data are obtained with approximately 10 metre vertical resolution (approximately 2 second sampling). The data held at the AADC (including the WOUDC data) are provided in approximately 50 metre vertical resolution (10 second sampling). The 2 second data can be provided on request, although in practice, the time constant of the electrochemical cell (1/e time constant of approximately 20 seconds) means that the higher resolution does not necessarily provide more information. The WOUDC files contain the most detailed information, including information on applied calibrations and corrections, and integrated ozone amounts. The main data fields presented are: air pressure (hPa), ozone partial pressure (mPa), temperature (K), wind speed (m/s), wind direction (degrees), elapsed time (sec), geopotential height (m), relative humidity (%), and electrochemical cell temperature (K). The BoM data contains a subset of this information, as well as accumulated ozone to each height (DU), and ozone remaining above this height to the top of the profile (DU). The estimated total ozone column (from the ground to the top of the atmosphere) is also provided based on methods by the World Meteorological Organisation (see code 2 on page 27 of http://woudc.org/archive/Documentation/GuideBooks/O3_guide.pdf), and McPeters and Labow, 2011 (McPeters, R. D. and Labow, G. J.: Climatology 2011: An MLS and sonde derived ozone climatology for satellite retrieval algorithms, J. Geophys. Res.-Atmos., 117, D10303, doi:10.1029/2011JD017006, 2012).