Other relevant info can be found at:
http://www.nbs.ac.uk/public/icd/metlog/
INTRODUCTION AND BACKGROUND
The British Antarctic Survey (BAS) maintains a meteorological observing
program at several stations in the British Antarctic Territory and in the
South Atlantic with archiving of the data undertaken at Cambridge and the
Meteorological Office. Surface and upper-air measurements carried out by the
Survey in the region commenced at or around the time of the International
Geophysical Year in 1956 although records dating back several decades in the
Antarctic Peninsula are available (see, for example, Jones and Limbert
(1989)). Much of the collected data has been included in an ORACLE computer
database at Cambridge over the last few years allowing quick data retrieval.
This short report describes the current database holdings with details of the
stations, observing practises, period of record, a detailed description of the
main parameters in the SYNOP database for less experienced users and examples
of how to extract the data using SQL (Structured Query Language), together
with information on various other related data on the database, e.g. monthly
mean temperature and pressure data for the Antarctic Peninsula and other parts
of the continent and the monthly location of the sea ice-open water margin in
the Southern Ocean.
Surface SYNOP data is available for 8 stations, namely Deception Island,
Grytviken, Adelaide Island, Signy Island, Port Stanley, Rothera Point, Halley
(formerly Halley Bay) and Faraday (formerly Argentine Islands). All but the
first 3 stations are operational. Those in operation have been located at the
same or a nearby site up to the present and, apart from Rothera Point, Signy
and Adelaide Island, have consistently carried out observations at 3 hourly
intervals. Data for Signy is intermittent and irregular until recently and
should be treated with caution from 1984 onward owing to the absence of a
trained meteorological observer at the site at most times (see below).
Meteorological observations are still undertaken by the Meteorological Office
in the Falklands at Mount Pleasant airport but data are only available on the
database for Port Stanley. Upper-air observations are currently only
undertaken by BAS at Halley but data for Faraday and Port Stanley are also on
the database.
The most important change in observing practise has been the changeover from
manual to automatic observing systems to do many of the routine synoptic
observations. This change occurred in the mid-1980's at Halley and Faraday,
and more recently also at Signy Island and Rothera Point, and involved the
deployment of SCAWS (Synoptic and Climatological Automatic Weather Station)
which was replaced in 1992 with MAWS (Modular Automatic Weather Station).
Apart from standard checks to the data, e.g. for extreme values, including
those due to equipment malfunction, and incorrect codes, the experience of
trained meteorological observers as well as further scrutiny of some of the
data suggests that the performance of automatic weather stations and
instruments after initial installation has been satisfactory. Instruments are
regularly and frequently calibrated. Regular on-site monitoring of the
performance of SCAWS and MAWS by observers, including comparisons with
measurements from standard meteorological equipment, also appears to have
prevented systematic errors in measurement (details of error checking that has
been systematically carried out on synoptic observations (but not on upper-air
data yet) are noted in Appendix A1). Apart from failure to launch radiosonde
balloons due to bad weather, a problem most common at Halley due to high
winds, serious problems in upper-air data collection have been confined to
Halley. Here, inaccurate wind directions and speeds between 1984 and 1991 have
periodically resulted from radio interference to the OMEGA windfinding system
under certain weather conditions. Following introduction of radiotheodolite
windfinding in 1992 this problem no longer occurs. At present upper-air data
should be treated with caution as they have yet to be fully checked.
SYNOP DATABASE
Description of the tables
Each ORACLE table contains SYNOP data for a number of parameters in column
format for each of the standard reporting hours (rows) and at hourly intervals
for automatic weather stations. The duration of the records for stations on
the database varies. In some cases the stations are no longer operational but
for others data may be available for nearby sites not maintained by BAS as
noted below. The frequency of observations varies between stations and also
at individual stations and, in some cases, not all parameters are recorded
(stored as null values in the tables). Prior to the mid-1980's all
observations were carried out manually. As noted below automatic weather
stations (see below) were introduced after this period at Faraday and Halley,
in 1988 at Signy Island and in 1990 at Rothera Point. These automatically log
all parameters apart from those that describe weather, cloud, visibility and
full date (as specified in section 2.2). 'SYNOP' as well as other ORACLE data
bases are all indexed (see below) permitting rapid data retrieval.
Description of each column
In the following, except for OBTIME, information is given on a) what the
parameter is (see section 7 and the Meteorological Office "Observer's
Handbook" for a detailed description of these), b) the data type of the
variable of the form integer (I), real (R) or character (C), c) whether the
variable is in measurement or WMO code form, d) how it is measured, e) valid
range in case of non-coded data. In d) the information in brackets refers to
automatic weather instrumentation. Missing values for all data columns are
left as null.
'OBTIME'
Date variable giving the calendar date and time of the observation in the form
YYYY-MON-DD:HH24:MI:SS where YYYY is the year, e.g. 1987, MON is month, e.g.
JAN, DD is day, e.g. 21, HH24 is the hour in the 24 hour clock, MI is minutes
pas the hour and SS is seconds past the minute (also see indexing below). The
default output format of OBTIME is DD-MON-YY.
'TOTAL_CLOUD_AMOUNT'
a) Total cloud amount, b) I, c) oktas (eighths cover), d) visual, e) from 0
to 9 where 0 is clear sky, 8=total cover and 9 is sky obscured.
'WIND_DIRECTION'
a) Direction from which wind blows, b) I, c) in tens of degrees from North via
East measured to the nearest 10 degrees averaged over 10 minutes (5 minutes
for MAWS), d) Munro direction vane (Vector Instruments), e) 0 to 360 where
zero denotes calm and values from 1 to 360 give the wind direction where 360
denotes direction from due north. A 999 value indicates direction is variable.
'WIND_SPEED'
a) Wind speed, b) R, c) in knots (measured to nearest 1 knot averaged over 10
minutes (5 minutes for MAWS), d) Munro cup generator (Vector Instruments) but
occasionally subjectively estimated by observer or determined by using hand
held equipment, e) 0 to 90 knots.
'VISIBILITY'
a) Visibility - "the greatest distance at which an object can be seen"
(Meteorological Office Observers Handbook, 1982) from the point of
observation, b) C, c) code (90 (less than 50 m) to 99 (greater than 50 km)
code format is used), d) manual.
'PRESENT_WEATHER'
a) Present weather conditions, b) C, c) code, d) manual.
'PAST_WEATHER'
a) Past weather conditions, b) C, c) code (code changed from one to two
characters in 1982), d) manual.
'MSL_PRESSURE'
a) Mean sea level pressure, b) R, c) measurement to nearest 0.1 mb, d) Kew
type or aneroid barometer (aneroid, KDG Setra barometer), e) 930 to 1030 mb.
'DRYBULB_TEMPERATURE'
a) Screen dry bulb temperature (Assman psychrometer at Halley for occasions
of wind speed <16 knots up to end of 1986), b) R, c) measurement to nearest
0.1øC, d) thermometer (platinum resistance thermometer (PRT), e) 26.3øC (at
Grytviken) to -55.3øC (at Halley).
'WETBULB_TEMPERATURE'
a) Screen wet bulb temperature, b) R, c) measurement to nearest 0.1øC, d)
thermometer (determined from PRT and humidity sensor readings (see below), e)
range varies between stations.
'VAPOUR_PRESSURE'
a) Saturation vapour pressure, b) R, c) measurement in mb and tenths of a mb,
(e.g. 49=4.9 mb) d) derived using wet and dry bulb temperature (PRT and
humidity sensor readings), e) 0 to 10 mb.
'RELATIVE_HUMIDITY'
a) Relative humidity, b) I, c) measurement to nearest 1%, d) derived from
DRYBULB and WETBULB measurement (PRT and humidity sensor readings), e) 0 to
102%
'LOW_CLOUD_AMOUNT'
a) Low cloud amount, b) I, c) as total_cloud_amount, d) manual
'LOW_CLOUD_TYPE'
a) Type of low cloud, b) C, c) code, d) manual
'MEDIUM_CLOUD_TYPE'
a) Type of medium cloud, b) C, c) code, d) manual
'HIGH_CLOUD_TYPE'
a) Type of high cloud, b) C, c) code, d) manual
'DEWPOINT'
a) Dewpoint temperature, b) R, c) measurement to nearest 0.1øC (rounded to
nearest whole degree prior to 1st January, 1986), d) derived from dry and wet
bulb measurements (PRT and humidity sensor readings), e) varies between
stations.
'FIRST_CLOUD_AMOUNT'
a) Amount of lowest layer of cloud, b) I, c) as total_cloud_amount, d) manual
'FIRST_CLOUD_TYPE'
a) Type of lowest layer of cloud, b) C, c) code, d) manual
'FIRST_CLOUD_HEIGHT'
a) Height of lowest layer of cloud, b) C, c) code, d) manual
'SECOND_CLOUD_AMOUNT'
a) Amount of second lowest layer of cloud, b) I, c) as total_cloud_amount, d)
manual
'SECOND_CLOUD_TYPE'
a) Type of second lowest layer of cloud, b) C, c) code, d) manual
'SECOND_CLOUD_HEIGHT'
a) Height of second lowest layer of cloud, b) C, c) code, d) manual
'THIRD_CLOUD_AMOUNT'
a) Amount of third lowest layer of cloud, b) I, c) code, d) manual
'THIRD_CLOUD_TYPE'
a) Type of third lowest layer of cloud, b) C, c) code, d) manual
'THIRD_CLOUD_HEIGHT'
a) Height of third lowest layer of cloud, b) C, c) code, d) manual
'SOURCE'
Source of synoptic observation in character form - one of either "BASYN SYNOP"
(manual observation on synoptic reporting hour), "SCAWS SYNOP" (automatic
observation on synoptic reporting hour),"SCAWS GMTOB" (automatic observation
at other hours available only from AWS). For observations from MAWS substitute
MAWS for SCAWS, e.g."MAWS SYNOP". Hourly observations for Halley in 1986 are
under review (see section 2.4.2) and are indicated as "SCAWS TEST".
Data availability
Note that cloud observations prior to 1960 (apart from total cloud amount) are
under review for all tables.
Faraday 89063 (formerly Argentine Islands, 88952)
a) Location: 65ø15'S, 64ø16'W; Alt: 11 m
b) Observations: continuous observations from January 1956 to present at 3
hour intervals (8 observations/day).
c) Equipment history: Manual observation for all parameters prior to
installation of SCAWS in April 1985. SCAWS in test phase until end of 1985
and replacing manual observations from January 1986. SCAWS replaced by MAWS
in March 1992. MAWS PRT is aspirated.
Halley 89022 (previously known as Halley Bay)
a) Location (as of January 1992): 75ø53'S, 26ø04'W; Alt: 37 m
The station is situated on a moving ice shelf and has been periodically
relocated over the recording period. Sites have all been located within about
10 km of the present position.
b) Observations: continuous observations from January 1957 to present at 3
hour intervals (8 observations/day). For the period of testing of SCAWS in
1986 manual 3 hourly observations ("BASYN SYNOP") are available on the
database (see section 2.2). Data included for other hours in this year is from
the automatic equipment.
c) Equipment history: Manual observation for all parameters up to December
1986. Installation of SCAWS in January 1986 and in test phase until end of
1986. SCAWS replaced by MAWS in February 1992. The hourly SCAWS data for 1986
should be treated with caution as it is suspected instruments may have been
improperly calibrated. MAWS PRT is aspirated.
Rothera Point 89062
a) Location: 67ø34'S, 68ø08'W; Alt: 16 m
b) Observations: continuous observations from March 1976 to present at 6 hour
intervals (4 observations/day). Only 2 observations/day (0000 and 1200Z) in
1976. Data gaps in 1976.
c) Equipment history: Manual observation for all parameters prior to
installation of MAWS in December 1990. MAWS in test phase until end of 1991
with manual observations of all parameters on the database up to this time.
Adelaide Island 88958
a) Location: 67ø46'S, 68ø55'W; Alt: 30 m
b) Observations: continuous observations from May 1962 to December 1975 at 3
hour intervals (8 observations/day).(station relocated to Rothera in 1976).
c) Equipment history: Manual observation for all parameters.
Signy Island 89042
a) Location: 60ø45'S, 45ø36'W; Alt: 7 m
b) Observations: continuous observations from January 1956 to December 1969
and January 1982 to present. Observations every 3 hours (8 observations/day)
in first period and from January 1989, and every 4 hours (4 observations/day)
at other times. Data complete up to 1969. Only wind speed, (no wind
direction), pressure and temperature from 1982 to 1987. Infrequent cloud and
visibility observations from 1988 to present, and gaps in other parameters due
to lack of trained observer.
c) Equipment history: Manual observation for all parameters until SCAWS
installed in 1988 and replaced by MAWS in 1992.
Deception Island 88938
a) Location: 62ø59'S, 60ø,34'W; Alt: 6 m
b) Observations: continuous observations from January 1959 to December 1967
when station closed. Observations every 3 hours (8 observations/day).
c) Equipment history: Manual observation for all parameters.
Grytviken 88903
a) Location: 54ø16'S, 36ø30'W; Alt: 2 m
b) Observations: continuous observations from January 1959 to December 1981
(with station closed in March 1982). Observations every 3 hours (8
observations/day) from 1959 to 1966 and from 1971 onward; otherwise every 6
hours (4 observations/day). Gaps in visibility and cloud observations from
1967 to 1970.
c) Equipment history: Manual observation for all parameters.
Port Stanley 88890
a) Location: 51ø42'S, 57ø52'W; Alt: 51 m
b) Observations: start in January 1958 and end in December 1967 on the
database (although this station remained open until April 1982 and
subsequently relocated to Mount Pleasant airport in 1984 under the
Meteorological Office). Observations made every 3 hours(8/day).
c) Equipment history: Manual observation for all parameters.
UPPER-AIR DATABASE
Description of the tables
Upper-air data for each station is stored in five tables containing
geopotential height, temperature, relative humidity and wind direction and
speed at standard pressure levels between 1000 and 10 mb. The standard time
of ascents is 1200Z but can be up to 2 hours earlier than this at times. The
table names are in the form: _temp_ where parameter is
'height' (geopotential height), 'humidity' (relative humidity), 'temperature'
(temperature), 'wind_direction' (wind direction) and 'wind_speed' (wind
speed). Missing values are indicated as null.
Description of each column
In the following I = integer and R = real.
In general there are 25 columns in each table. The 'OBTIME' is given in the
first column and is of identical form to that used in the SYNOP database (see
section 2.2). 24 columns in each of the five tables are to allow for
measurements of the different variables at the surface with variable name
'SURFACE', and the following standard pressure levels: 1000, 900, 850, 800,
700, 600, 500, 400, 300, 250, 200, 150, 100, 80, 70, 60, 50, 40, 30, 25, 20,
15, 10 mb. Measurements taken at the tropopause are included in the final
column with the variable name 'TROP'. The variable name of each of the
standard levels is a 'P' followed by the standard pressure level, e.g. P300.
For Halley an additional column is included for measurements at 925 mb made
from 1990 onward. Prior to 1984 the surface elevation is given in the SURFACE
parameter but the pressure at launch is supplied from 1984 onward.
Prior to 1961 the standard levels above 100 mb were at 80, 60, 50, 40, 30, 25
and 20 mb but then changed to 70, 50, 30, 25, 20, 15 and 10 mb. The
geopotential height (I) is to nearest metre, temperature (R) to nearest 0.1øC,
humidity (I) to nearest 1%, wind direction (I) to nearest whole degree and
wind speed (R) to nearest 0.5 knot.
Data availability
Faraday
a) Observations: The database contains observations from January 1956 to
December 1982 when ascents ceased (following a fire at the station). The
Faraday database is under review but is mostly complete up to 1975. Data
need to be checked for superadiabatic layers and hydrostatic balance before
use.
b) Flight frequency: once daily (occasional additional flights made at other
times for special studies).
c) Equipment history.
Radiosondes used:
Jan. 1956-Feb. 1971 : UK Met. Office MkIIb
Mar. 1971-Feb. 1975 : Graw M60
Mar. 1975-Jan. 1983 : VIZ (Beukers)
Windfinding:
Jul. 1954-Jan. 1963 : Pilot balloon theodolite
Apr. 1962-Jan. 1983 : Radar
Halley
a) Observations: The database is under review but contains mostly complete
observations from the start of observations in April 1957 up to 1974 as well
as from 1984 onward. The geopotential height of the 1000 mb standard pressure
level is estimated from the measured geopotential height for adjacent standard
levels using the hydrostatic equation. Null values appear in the tables for
a number of reasons including occasional failure to launch balloons - due to
adverse weather conditions (most common in winter) - and to track balloons,
as well as early bursting of balloons. Data for 900, 800 and 600 mb have not
been computed for 1984 to 1989. Incorrect wind measurements occur during the
period using OMEGA windfinding equipment (see section (c)). Quality control
of these data is not yet complete and other errors are known to exist. Data
should be checked for superadiabatic layers and hydrostatic balance before
use.
b) Flight frequency: once daily (with occasional additional flights made for
special studies at non-standard times).
c) Equipment history
Radiosondes used:
Apr. 1957-Feb. 1971 : UK Met. Office MkIIb
Mar. 1971-Feb. 1975 : Graw M60
Mar. 1975-Dec. 1983 : VIZ (Beukers)
Feb. 1984-Dec. 1991 : Vaisala RS80
Jan. 1992-present : AIR Intellisonde
Windfinding:
Apr. 1957-Aug. 1981 : Radar
Aug. 1981-Feb. 1984 : Pilot balloon theodolite
Feb. 1984-Dec. 1991 : OMEGA navaid
Jan. 1992-present : Radiotheodolite
Port Stanley
a) Observations: start in January 1956 and available on the database until
February 1968 (observations recommenced in 1984 at Mount Pleasant airfield -
see section 2.4.8). Quality control of these data is not yet complete and some
errors are known to exist. Data should be checked for superadiabatic layers
and hydrostatic balance before use.
b) Flight frequency: daily at 1200Z but only every 2 or 3 days in the latter
part of the database.
c) Equipment history
Radiosondes used: UK Met. Office MkIIb; Windfinding: Radar
AUTOMATIC WEATHER STATION database
Content
The tables contain the 3 hourly measurements of temperature, pressure, wind
speed and wind direction for the automatic weather stations, that are deployed
by the US, in the Antarctic. The table names are specified as NAME_AWS and the
locations and periods for which we have data are shown below.
AWS NAME FROM TO LAT LONG HT(m)
AGO_SITE 01-JAN-91 31-DEC-92 77 31'S 23 44'W 1545
ALLISON 28-JAN-86 31-JUL-87 89 53'S 60 00'W 2835
ASGARD 05-FEB-80 31-DEC-82 77 36'S 160 06'E 1750
BONAPART_POINT 01-JAN-92 31-DEC-92 64 47'S 63 04'W 8
BOWERS 11-JAN-86 25-AUG-86 85 12'S 163 24'E 2090
BUCKLE_ISLAND 01-JAN-87 31-JUL-88 66 54'S 163 12'E 520
BUTLER_ISLAND 01-MAR-86 31-DEC-92 72 13'S 60 20'W 91
BYRD 05-FEB-80 07-OCT-92 80 00'S 120 00'W 1530
BYRD_GLACIER 01-JAN-84 31-AUG-84 80 00'S 165 02'E 75
CAPE_ADAMS 29-JAN-89 22-SEP-92 75 01'S 62 32'W 25
CAPE_DENISON 01-JAN-90 31-DEC-91 67 01'S 142 41'E 31
CLEAN_AIR 01-JAN-86 31-JAN-91 89 57'S 00 01'W 2835
DOLLEMAN_ISLAND 01-JAN-87 31-DEC-88 70 36'S 61 00'W 396
DOME_C 05-FEB-80 31-DEC-92 74 30'S 123 00'E 3280
D_10 08-JAN-80 31-DEC-92 66 42'S 139 43'E 240
D_17 11-JAN-80 19-JUN-80 66 42'S 139 42'E 438
D_47 01-JAN-83 31-DEC-92 67 23'S 138 43'E 1560
D_57 01-JAN-81 31-DEC-87 68 11'S 137 31'E 2105
D_80 14-JAN-83 30-SEP-90 70 01'S 134 43'E 2500
ELAINE 28-JAN-86 17-SEP-88 83 09'S 174 28'E 60
FERRELL 10-DEC-80 27-AUG-92 78 01'S 170 48'E 45
FOGLE 25-JAN-84 05-JAN-85 77 49'S 166 45'E 202
GILL 01-JAN-85 31-DEC-92 80 02'S 178 38'W 55
JIMMY 02-DEC-81 30-APR-90 77 52'S 166 49'E 200
LARSEN_ICE 01-JAN-86 31-DEC-92 66 58'S 60 33'W 17
LAURIE 12-DEC-81 31-DEC-85 77 33'S 170 05'E 23
LETTAU 29-JAN-86 31-DEC-92 82 35'S 174 16'W 55
LINDA 01-JAN-91 30-APR-92 78 30'S 168 21'E 50
LYNN 01-JAN-88 31-DEC-92 74 14'S 160 17'E 1772
MANNING 01-DEC-80 31-DEC-85 78 46'S 166 51'E 66
MANUELA 01-JAN-84 31-DEC-92 74 53'S 163 36'E 80
MARBLE_POINT 05-FEB-80 31-DEC-92 77 26'S 163 45'E 120
MARILYN 01-JAN-87 31-DEC-92 79 57'S 164 58'E 75
MARTHA1 01-JAN-84 31-DEC-86 78 18'S 72 30'E 20
MARTHA2 21-JAN-87 13-FEB-92 78 23'S 173 22'W 18
MEELEY 01-JAN-81 31-DEC-85 78 15'S 170 11'E 49
MINNA_BLUFF 01-JAN-91 31-DEC-92 78 33'S 166 41'E 917
MT_EREBUS 01-DEC-89 16-OCT-90 77 32'S 167 09'E 3700
MT_HOWE 01-JAN-92 31-OCT-92 87 19'S 149 33'W 2400
NANCY 17-JAN-83 25-NOV-83 77 55'S 168 10'E 25
PATRICK 28-JAN-86 26-JUN-87 89 54'S 45 00'E 2835
PAT 01-JAN-89 31-DEC-90 74 53'S 163 06'E 30
PEGASUS 19-JAN-89 10-NOV-89 78 00'S 166 38'E 50
PEGASUS_NORTH 01-JAN-90 31-DEC-92 77 57'S 166 31'E 10
PEGASUS_SOUTH 01-JAN-91 31-JAN-91 78 02'S 166 36'E 10
PENGUIN_POINT 01-DEC-92 31-DEC-92 67 37'S 146 00'E 30
PORT_MARTIN 01-JAN-90 31-DEC-91 67 12'S 141 26'E 15
RACER_ROCK 01-OCT-89 31-DEC-92 64 16'S 61 54'W 17
SANDRA 01-JAN-89 31-DEC-92 74 29'S 160 29'E 1525
SCHWERDTFEGER 01-JAN-85 30-SEP-92 79 56'S 169 50'E 60
SCOTT_ISLAND 01-JAN-88 31-JAN-91 67 22'S 179 58'E 30
SHRISTI 01-JAN-88 30-SEP-92 74 42'S 161 34'E 1200
SIPLE 01-JAN-82 21-APR-92 75 54'S 84 00'W 1054
SUSHILA 01-JAN-88 30-SEP-91 74 25'S 161 19'E 1430
TIFFANY 24-JAN-84 31-DEC-85 78 00'S 168 12'E 25
URANUS_GLACIER 01-MAR-86 30-NOV-92 71 26'S 68 56'W 780
WHITLOCK 01-JAN-82 31-JAN-92 76 14'S 168 42'E 275
WILLIS_FIELD 25-JAN-92 30-NOV-92 77 07'S 167 00'E 20
WINDLESS_BIGHT 01-JAN-83 31-DEC-85 77 45'S 167 40'E 40
YOUNG_ISLAND 01-JAN-91 31-DEC-92 66 17'S 162 20'E 30
Data source
The data is collected and quality controlled by the University of
Wisconsin. No further error checking has been carried out . The potential
inaccuracies of data from unmanned weather stations must be borne in mind and
users should carry out their own data checks.
Table organisation
The tables contain 5 columns obtime, temperature, pressure, wind_speed
and wind_direction. The wind speed is in m/s.
DATA COLLECTED FROM THE GTS
Contents
There are two tables GTS_SYNOP and GTS_TEMP containing synoptic and
upper-air reports from most of the bases in the Antarctic. The bases and
periods covered are shown below.
GTS_TEMP
Station Station Name From To
85934 Punta 01-DEC-93 30-SEP-94
88889 MPA 01-DEC-93 30-SEP-94
89001 S.A.N.A.E 16-NOV-87 27-NOV-92
89002 G von Neumayer 21-DEC-87 30-SEP-94
89009 Amundsen-Scott 16-NOV-87 30-SEP-94
89022 Halley 16-NOV-87 30-SEP-94
89050 Bellingshausen 17-NOV-87 30-SEP-94
89055 Marambio 23-NOV-87 30-SEP-94
89512 Novolazarevskaya 16-NOV-87 29-FEB-92
89532 Syowa 16-NOV-87 30-SEP-94
89542 Molodeznaja 16-NOV-87 22-APR-94
89564 Mawson 16-NOV-87 30-SEP-94
89571 Davis 16-NOV-87 29-SEP-94
89592 Mirnij 16-NOV-87 30-SEP-94
89606 Vostok 16-NOV-87 07-JAN-92
89611 Casey 16-NOV-87 30-SEP-94
89642 Dumont D'urville 16-NOV-87 29-SEP-94
89657 Leningradskaja 16-NOV-87 31-DEC-90
89664 McMurdo 17-NOV-87 30-SEP-94
GTS_SYNOP
Station Station Name From To
85934 Punta 01-JAN-88 30-SEP-94
87925 Rio Gallegos 01-JAN-88 30-SEP-94
87938 Ushaia 01-JAN-88 30-SEP-94
88889 MPA 01-JAN-88 30-SEP-94
88903 Grytviken 01-JAN-88 30-SEP-94
88963 Esperenza 01-JAN-88 30-SEP-94
88968 Orcadas 01-JAN-88 30-SEP-94
89001 S.A.N.A.E 01-JAN-88 17-NOV-92
89002 G von Neumayer 01-JAN-88 30-SEP-94
89009 Amundsen-Scott 01-JAN-88 30-SEP-94
89022 Halley 01-JAN-88 30-SEP-94
89024 AGO1 (AWS) 24-SEP-91 19-JUL-93
89034 Belgrano 12-DEC-93 30-SEP-94
89042 Signy 02-JAN-88 30-SEP-94
89050 Bellingshausen 01-JAN-88 30-SEP-94
89053 Jubany 12-DEC-93 30-SEP-94
89054 Dinamet 12-DEC-93 30-SEP-94
89055 Marambio 01-JAN-88 30-SEP-94
89056 Frei 01-JAN-88 30-SEP-94
89057 Aruro Prat 12-DEC-93 30-SEP-94
89058 Great Wall 12-DEC-93 30-SEP-94
89059 Bernado O'Higgins 12-DEC-93 30-SEP-94
89061 Palmer 12-DEC-93 30-SEP-94
89062 Rothera 01-JAN-88 30-SEP-94
89063 Faraday 01-JAN-88 30-SEP-94
89065 Fossil Bluff 01-JAN-88 21-FEB-94
89066 San Martin 01-JAN-88 30-SEP-94
89251 King Sejong 12-DEC-93 30-SEP-94
89261 Racer Rock (AWS) 26-JUL-89 30-SEP-94
89262 Larsen (AWS) 16-JAN-89 30-SEP-94
89264 Uranus Gl.(AWS) 16-JAN-89 02-FEB-94
89266 Butler Is. (AWS) 16-JAN-89 30-SEP-94
89268 Cape Adams (AWS) 26-JUL-90 22-SEP-92
89284 Siple (AWS) 25-JUL-90 19-JUL-93
89324 Byrd (AWS) 16-JAN-89 30-SEP-94
89512 Novolazarevskaya 01-JAN-88 30-SEP-94
89532 Syowa 01-JAN-88 30-SEP-94
89542 Molodeznaja 01-JAN-88 30-SEP-94
89564 Mawson 01-JAN-88 30-SEP-94
89571 Davis 01-JAN-88 30-SEP-94
89573 Zhongshan 12-DEC-93 30-SEP-94
89592 Mirnij 01-JAN-88 30-SEP-94
89606 Vostok 01-JAN-88 09-FEB-94
89611 Casey 01-JAN-88 30-SEP-94
89642 Dumont D'urville 01-JAN-88 30-SEP-94
89657 Leningradskaja 01-JAN-88 27-MAR-91
89664 McMurdo 01-JAN-88 30-SEP-94
89705 AGO1 (AWS) 01-SEP-93 30-SEP-94
89828 Dome C (AWS) 16-JAN-89 30-SEP-94
89832 D-10 (AWS) 31-JUL-89 30-SEP-94
89834 D-47 (AWS) 09-OCT-91 30-SEP-94
89836 D-80 (AWS) 25-JUL-90 30-SEP-94
Sources
All the data was received over the Global Telecommunications System
(GTS). The data is incomplete for all stations and has been collected
primarily for intensive study of short periods; great care should be taken if
working out long term mean values.
Reports are recieved at 3 or 6 hourly intervals depending on the
station. Range error checking has been carried out on the data.
MEAN MONTHLY CLIMATE STATISTICS
Content
The table "jones_and_limbert" contains the mean monthly values of temperature
and mean sea level pressure or station pressure compiled for 30 stations
throughout Antarctica by Jones and Limbert (1989). The length of record varies
between stations but mostly dates from the 1950's and 60's and, apart from the
British Antarctic Survey sites in the Peninsula and at Halley, are to as
recently as 1988. Means for those Antarctic Survey stations still in operation
have been updated to June 1993.
Data sources
The data sources used by Jones and Limbert (1989) mainly consisted of the
World Weather Records covering the period 1951 to 1979 and Monthly Climate
Data for the World for the period from 1961 to 1988. Records from adjacent
stations for different periods were composited into single "station" records
such as for Rothera Point (see sections 2.4.3 and 2.4.4). Station reports have
been used to update the monthly means to June 1993 for the BAS stations that
continued to operate after 1988. More information on data sources and stations
included as well as details of station compositing can be found in Jones and
Limbert (1989).
Table organization
The table contains 5 columns: STATION (character), OBTIME(date),
DAY_NUMBER(integer), PRESSURE(real to nearest 0.1 mb) and TEMPERATURE(real to
nearest 0.1øC). DAY_NUMBER is the day number where day 0 is the 1st January,
1960 (day number is therefore an increasing negative number going back from
this date), and where the day number for a particular monthly mean is for the
first day of that month. OBTIME form is DD-MON-YY.
MONTHLY AND WEEKLY ICE EDGE POSITION IN SOUTHERN OCEAN
Content
The table "ice_edge" gives the monthly northern limit of the icepack in the
Southern Ocean from 1973 to 1991 at 10 degree intervals starting at 0øE and
finishing at 350øW derived by Jacka (1990). The position of the icepack limit
is for the middle of the month. The table "SIGRID" gives the corrosponding
weekly northern limit of the icepack in the Southern Ocean from 1973 to 1988
at 1 degree intervals.
Data sources
Data in both these tables is based on the Weekly ice charts produced by the
Navy/NOAA Joint Ice Center derived primarily from satellite passive microwave
measurements and visible and infra-red imagery, but also incorporating ship
and any other available observations. The limit of the ice is taken as where
the ice concentration is less than 10%.
Table organization
The table contains 4 columns: OBTIME(date), SASDAY(integer),
LONGITUDE(integer) and LATITUDE(real to nearest 0.1øC). OBTIME form is DD-MON-
YY. SASDAY is in the same form as DAY_NUMBER in the "jones_and_limbert" table.
SURFACE RADIATION AND SUNSHINE MEASUREMENTS
Contents
Hourly radiation and sunshine duration measurements are available for the BAS
sites at Halley and Faraday, both from 1986 onward, and for Signy Island from
1988 to date. Locations of the sites are noted in section 2. The table names
are in the form: _radiation, e.g. halley_radiation.
Data sources
BAS automatic weather station and observational data.
Table organization
Tables contain 5 columns: OBTIME(date) in DD-MON-YY (note hour is not
included), GMT - Greenwich mean time in HH form, e.g. 1300 is 1 PM, LAT giving
the Local Apparent Time also in HH form, SUN - the duration (minutes) of
sunshine in the hour proceeding the observation, e.g. from 1200 to 1300 GMT,
TOTAL_SUN - the total duration of sunshine in the current day up to the hour
of observation, RADIATION - solar radiation(wm-2) based on an average for the
60 minutes prior to the observation, UV (wm-2) - U.V radiation averaged for
the 60 minutes prior to the hour of the observation and TEMPERATURE -
temperature averaged over the 60 minutes before the observation.
Apart from temperature readings, all the parameters (except OBTIME that is in
date form) are in integer format. Temperature is a real measurement to the
nearest 0.1øC. Radiation and sunshine instruments are as follows:
Solar radiation : Solarimeter
Ultra-violet radiation : Eppley ultra-violet radiometer
Sunshine : Haenni sunshine detector
NOTES ON SYNOP OBSERVATIONS AND CODES
The following notes are intended to provide the inexperienced user with more
information on those parameters in the SYNOP database that are most likely to
be used. They should be used in conjunction with the description of the
different meteorological parameters and coding given in section 2. Please
contact the database manager if you need any more information.
Temperature measurement:
Air temperature measurements are made by conventional thermometers and
platinum resistance thermometers (PRT) housed in a Stevenson screen. The wet
bulb temperature (or ice bulb temperature for temperatures below freezing) is
used to calculate relative humidity, a measure of the water content of the air
as a fraction of the total water content if the air was saturated. Wet and dry
bulb readings are also used to determine the dew point temperature and
saturation vapour pressure. Following introduction of automatic observing
systems the various temperature measurements are now obtained using the
humidity probe and PRT readings.
Screen temperatures can occasionally exceed ambient air temperatures. This
problem, associated with a screen situated above a permanent snow/ice covered
surface, arises from a lack of ventilation of the screen in calm conditions
with solar radiation (direct and reflected from the surface) warming the
screen compared to its surrounds. This situation occurs at Halley and the MAWS
equipment here is now aspirated. Prior to introduction of SCAWS, Assman
psychrometers were used at Halley to estimate temperatures at wind speeds
below 16 knots. No aspiration was done during the SCAWS era and analysis of
the dry bulb temperature data at low wind speeds indicates a higher frequency
of temperatures above freezing from SCAWS compared to previous years and
apparent record high maxima in the summer months.
Cloud type:
The total_cloud_amount, low_cloud_amount, etc indicate the amount of sky
covered by cloud or a particular type of cloud, e.g. cumulus, cirrus. The
amount is given in eighths (oktas) i.e. 1= one eighth. For many purposes a
value of "9" in the amount column may be treated as an "8", i.e. overcast,
since there is no sun reaching the surface. A "9" indicates the sky is
obscured, e.g. due to fog.
The codes for the type of cloud in the "cloud_type" categories are:
0 - Cirrus
1 - Cirrocumulus
2 - Cirrostratus
3 - Altocumulus
4 - Altostratus
5 - Nimbostratus
6 - Stratocumulus
7 - Stratus
8 - Cumulus
9 - Cumulonimbus
/ - Cloud not visible owing to darkness, storm, fog etc
Height of cloud:
The height of cloud is the height of the cloud estimated from the ground
surface to cloud base. The coding used for the "first_cloud_height",
"second_cloud_height" and "third_cloud_height", of which the "first" is the
lowest, is
00 <100 ft
01 100 ft
02 200 ft
.
.
50 5000 ft
Codes 51 to 55 are not used.
For codes from 56 to 80 subtract 50 from the code and multiply by 1000, so
56 6000 ft
57 7000 ft
.
.
80 30000 ft
and
81 35000 ft
82 40000 ft
83 45000 ft
84 50000 ft
85 55000 ft
86 60000 ft
87 65000 ft
88 70000 ft
89 >70000 ft
Visibility:
Codes for the different distances are:
90 : < 50 m
91 : 50 m
92 : 200 m
93 : 500 m
94 : 1 km
95 : 2 km
96 : 4 km
97 : 10 km
98 : 20 km
99 : =>50 km
Pressure:
This is the pressure reduced to sea level in mb, not the station pressure.
Wind:
In meteorology wind direction always refers to the direction from which the
wind is blowing. Wind speed in the BAS database is always given in KNOTS.
Sunshine:
Sunshine is the total duration of sunshine at the surface in a given time
period.
Radiation:
The measured total incoming solar and U.V radiation at the surface averaged
over a specified period of time.
QUALITY CONTROL OF SYNOPTIC OBSERVATIONS
The following gives a short summary of the main error checking applied to
synoptic observations. These errors include those that arise from mistyping
with resulting mistakes in computation of some other related parameters.
Values were corrected by entering those recorded in the original
meteorological registers and by recomputation.
Wind Speed:
Wind speed > 50 knots compared with visibility and present weather.
In cases where the visibility, for example, is higher than expected the
apparent high speeds are checked in the register.
Wind Direction:
Wind direction <0 or >360 degrees. Missing values (999) appear when the
direction is highly variable such that a representative 10 minute average
cannot be obtained.
Visibility:
Values checked to be in range 90-99; cross-checking with visibility and
present weather.
Pressure:
5 consecutive pressures selected and if the difference between readings 2 and
3 and the difference between 3 and 4 exceeds the difference between 1 and 2
or between 4 and 5, readings 2,3 and 4 (the intermediate ones) are checked.
Temperature:
Dry bulb temperature checked against the extreme recorded maximum and minimum
for each station (errors mainly occur in the sign due to mistyping).
Wet(ice) bulb and dew-point temperature < dry bulb temperature. Checking for
valid cases of super saturation achieved by adding 1øC to the dry bulb values
to make them higher than wet(ice) bulb reading; remaining cases in which the
wet(ice) bulb temperature is warmer than the dry bulb are then taken to be
erroneous, the wet bulb temperature is set to equal the dry bulb temperature
and relative humidity is set to 100%. Corrections made for incorrect signs,
i.e. positive temperatures that should be negative, for cases of wrongly
calculated dew-point temperature using wet and dry bulb readings and for
incorrect wet-bulb temperature using dry and dew-point readings.
Vapour pressure and relative humidity:
RH < 103%
New RH values inserted in cases with corrected temperature readings.
Saturation vapour pressure obtained using the Goff-Gratch equations.
Cloud observations:
Total amount of low cloud > total cloud amount. Repeated in order for second
and third cloud amounts. Checking of cloud height and cross-checking of cloud
observations with weather conditions now in progress.
List of ORACLE Meteorological Tables
u_met.adelaide_synop
u_met.deception_synop
u_met.faraday_radiation
u_met.faraday_synop
u_met.faraday_temp_height
u_met.faraday_temp_humidity
u_met.faraday_temp_temperature
u_met.faraday_temp_wind_direction
u_met.faraday_temp_wind_speed
u_met.grytviken_synop
u_met.halley_radiation
u_met.halley_synop
u_met.halley_temp_height
u_met.halley_temp_humidity
u_met.halley_temp_temperature
u_met.halley_temp_wind_direction
u_met.halley_temp_wind_speed
u_met.iceberg
u_met.ice_edge
u_met.ice_edge_norms
u_met.jones_and_limbert
u_met.rothera_synop
u_met.signy_radiation
u_met.signy_synop
u_met.stanley_synop
u_met.stanley_temp_height
u_met.stanley_temp_humidity
u_met.stanley_temp_temperature
u_met.stanley_temp_wind_direction
u_met.stanley_temp_wind_speed
u_met.stations
u_met.svp
u_met.trig
Various other items are contained in the following tables for which more
details may be obtained from the database manager:
'stations' - list of meteorological stations in Antarctica
including station coordinates, elevation and
station number details.
'iceberg' - recorded positions of icebergs in the Southern Ocean
'ice_edge_norms' - climatological mean monthly positions of
the sea ice edge in the Southern Ocean
derived from the table 'ice_edge'.