Compilation of ozonesonde profiles from the Antarctic Georg-Forster-Station from 1985 to 1992

Compilation of ozonesonde profiles from the Antarctic Georg-Forster-Station from 1985 to 1992 G. König-Langlo and H. Gernandt Alfred Wegener Institute for Polar and Marine Research, Bussestraße 24, 27570 Bremerhaven, Germany Received: 29 July 2008 – Accepted: 5 September 2008 – Published: 22 September 2008 Correspondence to: G. König-Langlo (gert.koenig-langlo@awi.de) Published by Copernicus Publications.

Long-term studies of magnetospheric-ionospheric processes, geophysical investigations, biological studies and sea ice observations using satellite imaging were performed.
The station became known to the international scientific community when the vertical extent of the "ozone hole" in the southern polar stratosphere was firstly recorded by regular balloon-borne ozone observations in 1985 (Gernandt, 1987a, b).
The ozone sounding programme was a major contribution of the Meteorological Service to the Antarctic research of the German Democratic Republic (GDR).The station was established as a long-term ozone-sonde observatory in cooperation with the Russian Arctic and Antarctic Research Institute (AARI) and the Aerological Observatory Lindenberg (AOL) in order to study the climatology of the ozone layer in Published by Copernicus Publications.
G. König-Langlo and H. Gernandt: Antarctic ozonesonde profiles the southern polar stratosphere.The scientific and technical preparations were performed at AOL, where the training of personnel working at the station also took place.
The measurements began the year the ozone hole was discovered.They significantly contribute to other measurements made prior to and following 1985 at other stations.In 1985 these ozone soundings were the only record showing the change of vertical ozone distribution in the southern polar stratosphere in September and October.These results supplemented the strong negative trends in total ozone which had been observed at the British station Halley (Farman et al., 1985) for several years.Further studies focussed on understand the dynamical control of the chemical ozone loss in spring (Gernandt et al., 1989).For spring 1987 these investigations were extended by including balloon-borne observations from Halley, and the American Amundsen-Scott South Pole Station (Gernandt et al., 1995).The ozone data of Georg-Forster-Station were also compared with Arctic observations in order to qualitatively understand possible chemical ozone losses in the Arctic stratosphere (Müller et al., 1997).
The regular ozone soundings from 1985 until 1992 are a valuable reference data set after chemical ozone loss became a significant feature in the southern polar stratosphere.

Instrumentation
Since the end of 1974 balloon-borne electrochemical ozone sondes have been regularly launched, i.e. once or three times per week, at the Aerological Observatory Lindenberg (52.22 • N, 14.12 • E) of the Meteorological Service of GDR.The ozone sensor was developed by Rönnebeck and Sonntag (1976) on the basis of the Brewer-Mast principle (Brewer, Milford, 1960).The sondes of the type OSE-2, OSM-2, OSR (since April 1981), OSE-3 (since September 1986) and OSE-4 (since August 1989) were manufactured in cooperation with the Scientific Instrument Laboratory of the Academy of Sciences in Berlin.Prototypes of the sonde took part in the International Ozone Sonde Intercomparisons at Hohenpeissenberg in 1970 (Attmannsbacher, Dütsch, 1970) and in 1978 (Attmannspacher, Dütsch, 1981).
The ozone sensors were adapted to the Russian balloonborne radiosonde system Meteorit/RKS-5 for data transmission, receiving and processing of ozone partial pressure.The standard data, temperature and humidity, were obtained from the radiosonde RKS-5.Pressure, wind direction and wind speed were derived from radar measurements of the ground station Meteorit tracking the balloon flight.
The ozone partial pressure measurements were achieved by a small electrically driven gas sampling pump which forces ambient air through a sensing solution of an electrochemical cell (Brewer-Mast principle) which generates an electrical current proportional to the mass flow rate of ozone.
For balloon-borne ozone profile measurements a pump correction has to be applied in order to compensate for the decreasing pump efficiency with increasing height and changing air temperature.An inadequate pump correction and an erroneous estimate of residual ozone above the height of balloon burst may both contribute to the overall measurement error of the ozone profile.Usually an independent column ozone observation X D by spectrometer measurement is compared with the integrated column ozone X S between the ground level and the height of balloon burst plus an estimated residual ozone above that level to adjust the recorded profile values.The correction factor listed in Table 1 is Systematic differences and random errors of the electrochemical ozone sonde, type OSR, has been estimated by analysing 20 tandem ozone soundings at the Aerological Observatory Lindenberg in 1982 (Feister, Grasnick and Peters, 1985).Random errors are at their maximum of about 10 to 13% in the troposphere and above 32 km, and reach a minimum of 2 to 5% between 20 and 28 km.The mean random error is 11.5% in the troposphere, 7% in the stratosphere beneath the ozone maximum height (ca.22 km in Europe), and 5.6% above that height.Due to the lower temperature and different height distribution of the ozone the errors in Antarctica may differ from these findings.

Dataset
The dataset compiles 426 individual subsets of data, one for each sounding.Figure 1 presents an overview of the ozone measurements from the whole dataset.
The data were taken while the balloons were ascending.The soundings were terminated at the burst level of the balloons.The ascent velocity was about 5 m/s.During summertime -when the stratosphere was relatively warm -the balloons frequently reached levels above 30 000 m.During wintertime the low temperatures in the stratosphere (below −80 • C) lead to lower burst heights.Regular launches were performed once per week and during spring (September, October) up to three soundings per week.Occasionally strong Earth Syst.Sci.Data , 1, 1-5, 2009 www.earth-syst-sci-data.net/1/1/2009/

Dataset
The dataset compiles 426 individual subsets of data, one for each sounding.Fig. 1 presents an overview of the ozone measurements from the whole dataset.winds or technical problems (1989) made the measurements impossible.

Related datasets
Related datasets which were used with the data from Georg-Forster-Station.The locations of the corresponding Antarctic stations are shown in Fig. 2: Syowa, Antarctica, (69 • 00 S, 39 • 35 E): Ozone soundings since 1966, these data are used as a very important reference for the pre-ozone hole period in the Dronning Maud Land region (Chubachi, 1984, Solomon et al. 2005, Gernandt et al., 1996).
Faraday, Antarctica, (65 • 15 S, 64 • 16 W): A series of ozone flights was performed from March 1982 till April 1983.Individual flights do show indications of ozone depletion although it was not recognized at that time (Shanklin, 1985).
Neumayer-Station, Antarctica, (70  Ozone soundings performed since October 1991 data are used for comparisons (Gernandt et al., 1998, Rex et al., 2000) Neumayer-Station, Antarctica, (70°39'S, 8°15'W): After January 1992 the ozone soundings at Georg-Forster-Station were con Neumayer-Station 750 km further west (König-Langlo et al., 2006).At N ECC 5A/6A ozone sondes (VAISALA) were used.As the result of an intercom with TOMS data no correction factor was applied.The results of both sta presented as one time series, see Fig. 3.It is the longest nearly con measured time series of balloon-borne ozone observations since the chemic The combined time series of both stations show the development of the stratospheric ozone layers from 1985 until now.In terms of balloon observations it is the longest and thus unique record since the "ozone hole" has been discovered.Height-dependent trend and forcing studies were performed for the combined time series of balloon-borne ozone soundings (Gernandt et al., 1998).

Data access
The whole data set is published at http://dx.doi.org/10.1594/PANGAEA.547983.It contains the 426 doi-references of each single sounding.The whole dataset can be downloaded as one zipped file of tab-delimited textfiles.Each textfile includes all necessary metadata and a table containing all parameters of one sounding.No special software is needed to access the data.Special software is offered to convert or visualize the data, see http://pangaea.de/software/.Figure 1 can be taken as an example produced using ODV (Ocean Data View).
Acknowledgements.The ozone sounding programme at Georg-Forster-Station was funded by the Meteorological Service of the GDR as a contribution to the East-German Antarctic research programme.The scientific supervision and technical preparations of the Antarctic observations were performed at the Aerological Observatory Lindenberg (since 1990 Meteorological Observatory of the German Weather Service (DWD)).
The ozone sounding programme was developed and performed in cooperation with the Russian Arctic and Antarctic Research Institute (AARI), which provided the balloon launching facilities and radiosonde ground station Meteorit at Novolazarevskaya.
Support was given by the Japanese National Institute of Polar Research, which delivered special balloons to perform the ozone soundings during the winter period 1988.
Peter Plessing from the Meteorological Main Observatory of the Meteorological Service started the regular ozone soundings on 22 May 1985 and stayed for the first winter at the Georg-Forster-Station.Special thanks are given to him and to all following wintering over personal at Georg-Forster-Station and their Russian colleagues at Novolazarevskaya who performed and supported the ozone soundings from 1985 until 1992.
Edited by: D. Carlson operated German research base -later named Georg-Forster-Station -was established in 1976 in the Schirmacher Oasis at 70 • 46 S, 11 • 41 E. The station was permanently used and operated as an annex to the Russian station Novolazarevskaya until 1987, and then as a German Antarctic station named after the German natural scientists, author and revolutionary Georg Forster (1754-1794) until 1993.

Figure 1 :Figure 1 .
Figure 1: Time-height sections the annual ozone variation over Georg-Forster-Station

Figure 2 :
Figure 2: Location of Georg-Forster-Station and all other Antarctic station related datasets

Figure 2 .
Figure 2. Location of Georg-Forster-Station and all other Antarctic stations with related datasets.

Table 1 .
Correction factor C and standard deviation SD as obtained by spectrometer measurements of column ozone and column ozone obtained by profile integration at Georg-Forster-Station for October 1987 to 1991.