Rothera Phase 1 Site History

History Summary

Station Name Rothera Phase 1
Latitude 67° 34.3' S
Country U.K.
Longitude 068° 07.7' W
WOCE No 9100
Time Reference GMT(00-23 hours)
Contributor Proudman Oceanographic Laboratory,
Joseph Proudman Building,
6 Brownlow Street,
Liverpool,
L3 5DA. U.K.
Observation Period Nov 1992 - Oct 1999
Instrument Type 1992 - 1994 Aanderra WLR PTR475 1994 - 1999 Aanderra SRL/WLR
Site of Gauge Sea water well

Parameters recorded

Period Parameters Sample Interval
11 1992 - 03 1993 ST,SSP,PR 60 mins
12 1993 - 12 1994 ST,LT,AP,SSP,HTP 15 mins
01 1995 - 12 1995 ST,LT,AP,SSP,HTP 15 mins
01 1996 - 11 1996 ST,LT,AP,SSP,HTP 15 mins
01 1997 - 12 1997 ST,LT,WT,AP,SSP,HTP 15 mins
12 1997 - 11 1998 ST,LT,WT,AP,SSP,HTP 15 mins
12 1998 - 10 1999 ST,LT,WT,AP,SSP,HTP 15 mins

where

Completeness Index

Year CI (%) Year CI (%)
1992 11.2 1993 76.2
1994 91.0 1995 53.7
1996 99.4 1997 100
1998 98.8 1999 75.1

Note: In 1998 91% of the data were corrupted (Quality Index 7.4%)

Datum Information

Not yet available.

Quality Assessment

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


December 1992 to December 1994

Period Parameters Comments
11 1992 - 03 1993 SSP No gaps (>6 hrs)
  All No spikes or gaps.
Data time shifted by -2.00 hrs, for harmonic constants to agree with those from later records.
12 1993 - 12 1994 SSP Gaps: 87-97(1994),334-335(1994),337-339(1994)
  All Detailed in the following table
Spikes and Gaps December 1993 to December 1994
Start End  
Scan Flag Year Day Hour Scan Flag Year Day Hour Reason for Flag/Solution
1 1 93 342 1.875 42 1 93 342 12.125 Datum correction in HTP record. Corrected by adding 147 mb to first 41 values, then correcting spike at scan 42.
150 1 93 343 15.125 210 1 93 344 6.125 Spikes + floor problems in HTP record 'corrected' by relating to SSP record
241 1 93 344 13.875 242 1 93 344 14.125 Spikes in ST record, solved by interpolation.
243 1 93 344 14.375 249 1 93 344 15.875 Dropout on all channels, filled using interpolated values.
250 1 93 344 16.125 263 1 93 344 19.375 ST record problems. Corrected by interpolation
483 1 93 347 2.375 510 1 93 347 9.125 HTP gauge. Problem with peak + cut off. Filled by relating to SSP record
570 1 93 348 0.125 613 1 93 348 10.875 HTP tide gauge. Problem with peak + cut off. Filled by relating to SSP record
662 1 93 348 23.125 726 1 93 349 15.125 HTP gauge. Problem with peak + cut off. Filled by relating to SSP record
1050 1 93 353 0.125 1051 1 93 353 0.375 Spike in HTP signal. Replaced by interpolating.
1240 1 93 354 23.625 1268 1 93 355 6.626 HTP gauge. Problem with peak + cut off. Filled by relating to SSP record
10629 1 94 87 18.879 11587 1 94 97 18.380 Dropout on all channels (break in record). Values not filled.
26159 1 94 2 49 13.385 26160 1 94 249 13.635 Spike in HTP record. Replaced by interpolated value
29352 1 94 282 19.637 29365 1 94 282 22.887 Spikes in SSP record. Replaced using interpolated values
34347 1 94 334 20.389 34373 1 94 335 2.889 Dropout in record. SSP and AP filled by interpolation. Other channels left blank.
34526 1 94 336 17.139 34549 1 94 336 22.889 Dropout on all channels. SSP, AP and HTP channels filled by interpolation
34598 1 94 337 11.139 34789 1 94 3 39 11.000 Dropout on all channels. Gap too large to fill.

Harmonic analysis of the file gives excellent agreement with later files, suggesting that overall, the timings are good.

Datum of HTP gauge drifts 30 mb over first 5000 scans, before settling. Appear to have some sort of 'overshoot' in HTP record between scans 17000 and 23000. Over the whole record, there's a steady drift in HTP datum of 4 mbar. Comparing the SSP and HTP sensors suggests that 3 mbar of this drift is due to the HTP sensor.


January to December 1995

Period Parameters Comment
01 1995 - 12 1995 All Gap : 62-227(1995)

Agreement between HTP and SSP, over the high water period, is quite poor, prior to the gap in the data. There is a variability of approximately 1.5 mbar, and an offset of of 3 mbar between the two signals.

Comparing HTP and AP, the HTP cut off is very well defined prior to the gap in the data. There are some spikes, however only on one occasion, is this greater than 1 mbar. Following the data gap, the HTP record is very 'noisy' until day 280, where there is an apparent datum shift. The recorded pressure difference at LW, varies between 224-226 mbar.

The residuals appear very good. There is a spike at day 299, and a drop out between day 335(14.875) - day 336(19.625) which has not be infilled. Day 339 (16.125 - 16.375) has been corrected, with data based on the harmonic analysis predictions.

Harmonic constants agree well with the other files.


January to November 1996

Period Parameters Comment
01 1996 - 11 1996 All Gaps : None
  SSP Spikes : 205-275
  HTP Spikes : 175,205-243

HTP definition is very poor, until day 135. As comparisons between AP and LW HTP are generally good, it appears that there may be a problem with the SSP.

Residuals appear excellent, harmonic constants are in good agreement with the other data.


January 1997 to December 1997

Period Parameters Comment
01 1997 - 12 1997 All Gaps : None
Spikes : None
Timing : 335 onwards - see note below.

Comparing HTP and AP gives a 12.7 mbar offset at LW. HTP cut-offs are generally well defined, although there are some overshoots.

SSP and HTP show differences between the observed full tide at times.

Residuals look excellent until day 335, when it looks like there is a timing error. Harmonic constants are in excellent agreement with other files.


December 1997 to November 1998

Period Parameters Comment
12 1997 - 11 1998   SSP data very poor, due to sensor flooding. HTP data appears reasonable.

It is recommended these data not be used. However, it maybe possible to reconstruct the signal from the HTP sensors using predictions to infill the low tide.


December 1998 to October 1999

Period Parameters Comment
12 1998 - 10 1999 SSP Gaps : 361 (1998) Infilled by interpolation
Sensor failed : 261 (1999)
All Gap : 361
Sensors failed: HTP 275(1999), AP 274 (1999) ST 265 (1999)

Comparison between HTP and AP, also SSP and HTP indicate a 2 mbar drift on the HTP sensor over the period of the data.

Residuals show intermittent timing errors. Harmonic contstants are in excellent agreement with previous data files.