Metadata about the BAS ozone data
General
A paper describing the instrument meta data and observations is in preparation.
ThedatashouldbecreditedtoJDShanklin, BritishAntarctic Survey, Madingley Road, Cambridge, England. CB3 0ET
Station names:
Faraday
. 65°15'S, 64°16'W. Originally known as Argentine Islands (which is actually a
group of islands off the coast of the Antarctic Peninsula) the station became
known as Faraday in the mid 1970s. In 1996 it was handed over to the
Ukraine and its name changed to Vernadsky. In publications, the name
Faraday should be used when referring to data prior to 1996 and Faraday/Vernadsky
thereafter.
Halley
. 75°35'S, 26°36'W. Please note that the station name is Halley and this
should be used in all publications. The
geographical feature known as Halley Bay (which the station was called when
first set up in 1956) no longer exists. The station is on a floating
ice-shelf and moves over time. The position given is the current one, but
the actual location is likely to be within 15km of this.
King Edward Point.
54°16'S, 36°30'W. The station at King
Edward Point is near Grytviken, in Cumberland Bay, South Georgia.
Observations ceased due to military action in 1982 April.
Rothera.
67°34'S, 68°08'W. The name Rothera should be used in publications.
The SAOZ instrument can make observations throughout the year.
Observing season
Mu
King Edward Point
Faraday
Halley
2.0
Sep 07 - Apr 05
Oct
06 - Mar 08
Nov
04 - Feb 07
2.6
Aug 17 - Apr 26
Sep
15 - Mar 27
Oct
13 - Mar 01
3.2
Aug 01 - May 11
Sep
04 - Apr 08
Oct
01 - Mar 12
3.8
Jul 17 - May 26
Aug
27 - Apr 16
Sep
23 - Mar 20
4.4
Jun 25 - Jun 17
Aug
20 - Apr 23
Sep
18 - Mar 26
5.0
All year
Aug
15 - Apr 28
Sep
13 - Mar 30
5.6
All Year
Aug
10 - May 02
Sep
09 - Apr 03
6.2
All year
Aug
06 - May 06
Sep
06 - Dec 07
Jan 04 - Apr 06
6.8
All year
Aug
03 - May 10
Sep
04 - Nov 30
Jan 12 - Apr 08
7.4
All year
Jul
30 - May 13
Sep 02 - Nov 25
Jan
17 - Apr 10
8.0
All year
Jul
28 - May 16
Aug
30 - Nov 22
Jan 20 - Apr 12
8.6
All year
Jul
24 - May 19
Aug
29 - Nov 19
Jan
23 - Apr 14
9.2
All year
Jul
21 - May 22
Aug
27 - Nov 16
Jan 26 - Apr 16
Instruments
Datasets - ozone
All observations at Halley and Vernadsky are made with the Dobson ozone spectrophotometer.
Observations with Dobson 103 (with valve electronics and mechanical commutator) ceased at Halley on 2005 December 26 and observations with Dobson 73 (with modern electronics) commenced on 2005 December 24. The short overlap period allowed the instrument constants for both instruments to be slightly adjusted. Observations with Dobson 31 (with valve electronics and mechanical commutator) ceased at Vernadsky on 2005 March 29 and observations with Dobson 123 (with modern electronics) commenced on 2005 March 27. The short overlap period allowed the instrument constants for both instruments to be slightly adjusted. During the overlap periods a mean of both instruments is given. Ozone values from both the refurbished Dobsons are likely to undergo frequent revision until the instrument constants are well determined. Ozone values from the old instruments are also likely to undergo revisions following both the on-site intercomparisons, and intercomparisons at Hoenpeissenberg.
Daily
The daily data sets are divided into seasonal blocks starting on
August 1st each year and ending on 30th April. They contain the provisional ozone data for 1972 - 2005
obtained using the
Dobson ozone spectrophotometer. The definitive instrument and
zenith calibration values have not yet been determined. A daily
mean value is given, using all the observations for that day,
assigning equal weight to each. The final daily values may differ
from those given here, but should not differ from them by more
than 5%. A few moon
observations which have been carried out outside this period are
not included in this data set, but are available on request. A
value of 0 indicates that no measurement was made on that day.
Some experimental zenith observations at low solar elevations are
included from April 1993 onwards, these have lower accuracies
than normal observations. The Halley data for 1987/88 includes
the results from ozonesonde flights.
Monthly
The monthly data sets run from August to April. Data for 1957 - 1972
was published in BAS Scientific Report No 90 in 1975 and used
ozone absorption coefficients determined by Powell, which are the same as those
of Vigroux for AD, but are otherwise different. These ozone
values have been approximately corrected to the Bass-Pauer coefficients using
the WMO recommended factor of 0.9743. Note that this correction factor is
for the US Standard Atmosphere, however the Antarctic atmosphere is some way
from this and the correction could be improved. Data after this period is
reduced using the standard Bass-Pauer coefficients as published in Komhyr et al.
Rothera
The SAOZ instrument at Rothera measured total column
nitrogen dioxide and ozone from 1997 to 2007. The values given here are
preliminary and only show general trends in ozone amounts. In particular,
the calibration of the instrument is such that it reads about 10% lower than a
Dobson at values around 100 DU. A new SAOZ type instrument was installed during
the 2006/7 season and it became the operational instrument from 2008 January 1.
The instrument constants for the new SAOZ were revised in mid July 2008, and
previously published values were increased by about 2%. Following a
station power cut in mid June 2011, some data was lost and when data recording
resumed an incorrect time was recorded. This has been corrected, however
the data between 2011 June 16 and 2011 June 29 may contain residual errors.
There is also a Bentham spectro-radiometer at Rothera, which can be used to compute ozone levels. The original instrument was destroyed in a fire on 2001 September 28, however a replacement was commissioned and became operational on 2003 March 3. For further information on this data set and permission to use it please contact Paul Geissler at BAS. All values have been updated to the TOMS 8 algorithm. The uv data is available from the WOUVDC.
Datasets - temperature
The 70 hPa pressure level is close to the height of the maximum ozone concentration, however this was not always reached by balloons. The 100 hPa level is therefore used as a reference. Over the last 30 years the mean 100 hPa temperature has declined in most months. The most notable change is in November at Halley.
Halley
Radiosondes are released daily at Halley. The sonde
type changed from Vaisala RS80 to Vaisala RS92 in 2006 January.
Antarctic Peninsula
The record is a composite from several
stations and the balance has changed with time. Currently, there are flights from Marambio
as part of a spring-time ozone sonde campaign, however these do not always get
onto the GTS. The Polarstern was stationed in the western Weddell Sea from early December 2004
to early January 2005 and launched one or two sondes each day; when in the area
her routine flights are included. There have been a few ozone sonde flights from Ferraz, but these
have not been included in the record as they were not distributed on the GTS. No sondes are currently launched
at Bellingshausen or Vernadsky. Vaisala RS92 radiosondes are
currently released four times a week at Rothera and these form the primary
contribution to the record. There has been a radiosonde
programme of several flights per week at Rothera since 2003 March, increasing to
daily flights for the QUOBI project from mid June to mid October 2003. Strong
winds on 2004 October 2 & 3 damaged the hangar at Rothera and this
significantly restricted the conditions under which sondes could be launched.
Sonde type changed from RS80 to RS92 in 2007. A new launch facility become
operational in 2007, and the processing system was upgraded from an MW15 to an
MW31 in 2008 January, though this failed during the winter and flight control
has reverted to the MW15.