Tristan da Cunha Phase 1 Site History

History Summary

Station Name Tristan da Cunha
Latitude 37° 03.0' S
Longitude 012° 18.0' W
Country U.K.
Gloss No 266
Time Reference GMT(00-23 hours)
Contributor Proudman Oceanographic Laboratory,
Joseph Proudman Building,
6 Brownlow Street,
Liverpool,
L3 5DA. U.K.
Observation Period October 1984 - December 1998
(Site has not been visited to download data since Jan 1999)
Instrument Type Oct 1984 - Oct 1986: Aanderaa bubbler
Oct 1986 - Dec 1992: Digiquartz pressure sensor with telexed data transmission.
(NB Note in Quality Assessment section below)
Jan 1993 - Dec 1997: B-type Gauge (Woodworth et al. 1996)
Site of Gauge Tristan da Cunha Harbour.

Parameters Recorded

Period Parameters Sample Interval
10 1984 - 11 1985 AP,SP 60 mins
11 1985 - 05 1986 SP 30 mins
06 1986 - 10 1986 AP,TP 30 mins
10 1986 - 10 1987 ST,AP,TP,SSP 15 mins
10 1987 - 10 1988 ST,AP,TP,SSP 15 mins
10 1988 - 02 1989 ST,AP,TP,SSP 60 mins
02 1989 - 02 1990 ST,AP,TP,SSP 15 mins
02 1990 - 10 1990 ST,AP,TP,SSP 15 mins
10 1990 - 01 1992 ST,AP,TP,SSP 60 mins
01 1992 - 12 1992 ST,AP,TP,SSP 15 mins
01 1993 - 02 1994 ST,SSP,HTP,SSP 7.5 mins
02 1994 - 02 1995 ST,AP,SP,SSP,SSP 15 mins
02 1995 - 01 1996 ST,AP,LT,SSP,HTP 15 mins
01 1996 - 12 1997 ST,AP,LT,SP,SSP,HTP 15 mins
01 1998 - 12 1998 ST,AP,LT,SSP,HTP 15 mins

where:

Data Return

Year Completeness
Index(%)
Year Completeness
Index(%)
1984 16.7 1985 98.6
1986 87.0 1987 99.5
1988 80.1 1989 88.5
1990 99.5 1991 98.9
1992 93.7 1993 92.1
1994 98.6 1995 99.9
1996 100 1997 99.5
1998 97.8    

Datum Information

Not available

Quality Assessment

All data have been tidally analysed and constants and residuals checked. Records have been visually inspected for spikes and timing shifts. Timing and residuals appear satisfactory. However due to instrumentation drift, datum problems etc the contributor recommends, that these data should only be used for surges and short term variability and not for long term sea level studies.

Please Note for data Oct 1986 to Dec 1992 . Datums for telexed transmitted data and logger recorded data, for the same period, differ. Telex transmitted data is 0.15 db higher than logger recorded data, the latter is assumed to be correct. Where files consist of a combination of both, telexed and logger recorded data, datum shifts are observed.

Period Parameters Comments
10 1984 - 11 1985 AP Gap: (1984)305 - (1985)001,(1985)215 - 323
  SP Datum Shift: 02 May 1985 0700 hrs -0.2 dbars
Datum Shift: 04 May 1985 0900 hrs +0.2 dbars
Questionable Fluctuations: None
11 1985 - 05 1986 SP Gap: None Marked: (1986) 044,065,108,115
Questionable Fluctuations: None
06 1986 - 10 1986 AP Gap: (1986)180 - 273
  SP Gap: (1986)283 - 284
Questionable Fluctuations: None
10 1986 - 10 1987 AP Gap: (1987)270 - 278
  TP Datum Shift: (1987) 270 see note above
Datum Shift: (1987) 278 see note above
Questionable Fluctuations: None
10 1987 - 10 1988 AP Gap: (1988) 104 - 293
  TP Datum Shift: (1987) 104 see note above
Questionable Fluctuations: None
10 1988 - 02 1989 AP Gap: (1988) 293, 314 - (1989) 039
  ST Gap: (1988) 293, 314 - (1989) 0309
  TP Datum shift: (1988) 314 see note above
Questionable Fluctuations: None
02 1989 - 02 1990 AP Gap: (1990) 038
Questionable Fluctuations: None
02 1990 - 10 1990 All Gaps: None
Questionable Fluctuations: None
10 1990 - 01 1992 AP Gap: (1991) 115-120,266-274,274-275
  ST Gap: (1991) 115-120,266-274,274-275
  TP Gap: (1991) 115-120,266-274,274-275
Questionable Fluctuations: None
01 1992 - 12 1992   All Datum shift: (1992) 012 see note above
  ST Marked: (1992) 94-95,160,161-162,170, 174,175-176,177,289,332
Questionable Fluctuations: None
01 1993 - 02 1994 SSP PRSTPS02 - Gap: (1993)099 - (1994)034
  HTP Gap: (1993)099 - (1994)034
  ST Gap: (1993)099 - (1994)034
  SSP PRSTPS01 - None
All Marked: None
Questionable Fluctuations: None
02 1994 - 02 1995 All Gaps: None
Marked: None
Questionable Fluctuations: None
02 1995 - 01 1996 SSP Gap: (1995)054 - (1995)055
  HTP Gap: (1995)054 - (1995)055
  ST Gap: (1995)054 - (1995)055
01 1996 - 12 1997 All Gaps: None
Marked: None
Questionable Fluctuations: None
01 1998 - 12 1998 SSP Marked: (1998) 010,154-362
Questionable Fluctuations: 138-139
HTP Marked: (1998) 119-362
Half tide sensor does not always record the top of the tide.
  ST Marked: (1998) 119,128-362
  AP,LT Gaps: None
Marked: None
Questionable Fluctuations: None

Reference

Woodworth, P.L., Vassie, J.M., Spencer, R. and Smith, D.E. 1996.
Precise datum control for pressure tide gauges. Marine Geodesy, 19(1), 1-20.