St. Helena Phase 2 Site History

History Summary

Station Name St. Helena Phase 2
Latitude 15° 55.0' S
Longitude 005° 43.0' W
Country U.K.
Gloss No 264
Time Reference GMT(00-23 hours)
Contributor Proudman Oceanographic Laboratory,
Joseph Proudman Building,
6 Brownlow Street,
Liverpool,
L3 5DA. U.K.
Observation Period June 1993 - October 2001
Instrument Type B Gauge (Woodworth et al. 1996)
Site of Gauge Jamestown Harbour, by the landing steps.

Parameters recorded

Period CI(%) Parameters Sample Interval
06 1993 - 09 1993 100 ST,BT,AP,SL,SSP,HTP 15 mins
11 1993 - 02 1995 100 ST,BT,AP,SL,SSP,HTP 15 mins
02 1995 - 10 1995 100 ST,BT,AP,SL,SSP,HTP 15 mins
10 1995 - 10 1996 96 ST,BT,AP,SL,SSP,HTP 15 mins
04 1997 - 12 1997 100 ST,BT,AP,SL,SSP,HTP 15 mins
01 1998 - 07 1998 100 ST,BT,AP,SL,SSP,HTP 15 mins
07 1998 - 06 2000 99 ST,BT,AP,SL,SSP,HTP 15 mins
06 2000 - 10 2001 100 ST,BT,AP,SL,SSP,HTP 15 mins

where:

Reference Level

Sea level was recorded with respect to 'ST.HELENA B-DATUM JUNE 1993' until 1996, then with respect to 'ST.HELENA B-DATUM APRIL 1997'. The new datum is known relative to the old one through levelling, and is 18.0cm ABOVE it.

Quality Assessment

All data have been tidally analysed and constants and residuals checked. Records have been visually inspected for spikes, timing and datum shifts.

Possible datum shift (SSP and HTP) 04 Feb 1995 +20cm
Possible datum shift (SSP and HTP) 23 Oct 1995 -20cm
Possible datum shift (SSP, HTP and SL) 07 Apr 1997 -18cm (see comment on B-DATUM above)

Period Parameters Comments
06 1993 - 09 1993 All None
11 1993 - 02 1995 All None
02 1995 - 10 1995 All None
10 1995 - 10 1996

SSP

HTP

SL

Gap: (1996) 190-192,221-222

Gap: (1996) 190-192,221-222

Gap: (1996) 190-192,221-222

04 1997 - 12 1997 All None
01 1998 - 07 1998 All None
07 1998 - 06 2000

SL

SSP,HTP

BT

AP

ST

Null values on (1999)007,059,114,322,362

Marked: (1999)007,059,114,322,362

Marked: (1998)241,364 (1999)007,059,114,322,362

Marked: (1998)317 (1999)007,059,114,322,362

Many spikes marked. Use with caution.

06 2000 - 10 2001

SL

ST

Marked: (2000)183 (2001)155

Many spikes marked.

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.