Valparaiso-B (Chile) Site History

History Summary

Station Valparaiso-B
Country Chile
Latitude 33° 02.0' S
Longitude 071° 38.0' W
GLOSS No 175
Time Reference GMT (hours 00-23)
Contributor Servicio Hidrografico y Oceanografico de la Armada (SHOA)
Instrument Type
  • Bristol bubbler (8/1982 - 12/1985)
  • Metercraft bubbler (12/1985 - 1998). Primary gauge 12/1985-19/08/1997
  • Metercraft bubbler attached to Handar 540. Primary gauge 01/10/1998-08/11/1998. After 08/11/98, attached to Handar 555.
  • Handar Encoder (12/1985 - 1996). Backup gauge.
  • Aquatrak acoustic gauge (AAG) with Sutron recording platform (1993-08/11/1998) then with Handar 555 platform (08/11/1998 - present). Primary gauge 20/08/1997 - 30/09/1998 and 09/11/1998 - present.
Site of Gauge  
Observational periods 1982 - present

Reference Level

The originators have related the data to tide staff zero which is linked to a fixed set of benchmarks. Specifically, BM #2 (established 1941) is used as a historical datum. However, the data have several segments with questionable levelling that can not be corrected with levelling information from SHOA or from the original rolls, which have been misplaced:

Period (day/month/year) Comment
01/01/1983 - 07/02/1983 Low relative to Caldera
01/07/1983 - 09/09/1983 High relative to Caldera
01/01/1985 Suspicious rise of 10 cm
03/03/1985 - 15/07/1985 Linear trend increase of about 16 cm following the earthquake of 03/03/1985

Several segments with obvious shifts have warranted adjustment based on comparisons with Caldera and analysis of residuals (observed data minus predicted tides). These adjustements contain uncertainty of a few cm.

Period ((hour)day/month/year) Value added to original(mm)
(04)03/11/82 - (02)01/12/82 +100
(14)11/08/85 - (16)14/08/85 - 65
(17)14/08/85 - (23)31/12/87 -335
(13)18/10/95 - (14)27/11/95 50

Data from 1988-1990 were received with the reference level tied to the BM #2 (1941) while data for other time periods were received without linking the data to BM #2. Thus, the following level adjustments have been applied to the original data based on SHOA geodetic level records:

Period (day/month/year) Value added to original(mm)
01/01/1982 - 31/12/1987 -400
01/01/1991 - 31/12/1996 -728

This series is independent of Valparaiso-A because of a large unresolved reference level jump.

Tide Gauge Benchmark (TGBM) Description

BM Control This is a 6 cm bronze disk stamped 'Cota Control' set in cement at the north side in the base of the tide house.
BM No. 7 This is a 6 cm bronze disk stamped CF 7, is set in cement at the west side of the building, located 60 m east of the tide house.
BM No. 2 CF 3 1941

Benchmark Relationships

BM Control - 1985-1990.

BM No. 7 - 1950-1990.

Quality Assessment by the UH Sea Level Centre

Comment

The daily means agree reasonably with Caldera before the earthquake of 3/3/85 with the exception of the questionable segments as noted above. After 15/07/85, the linearly increasing trend ends and the daily means then agree well with Caldera. The linear trend of 3/3/85-15/07/85 is associated with the subsidence of the adjacent land and the pier which supports the installation. * below indicates gaps filled with Encoder data, # for Bubbler data (received via satellite), and $ for AAG. In comparison with the NOAA gauge, this series is suspiciously high by 5 cm from 8 July to 23 August 1996.

The extreme peak on 17 August 1997 is due to a storm.

Year CI(%) Missing Data Replaced Gaps or Bad Data Questionable Fluctuations
1982 41 303-307 (02)256-(08)256 287-291,309-310,364-365
1983 100 none (19)014-(06)015 (04)021-(03)022 (06)220-(12)220 (22)293-(15)294 4-5,55-56,101-102,105-107,110-122,125-126,128-130,133,138-139,189-195,244-255,277
1984 96 12-25 (16)146-(03)147 (06)179-(13)179 (23)192-(08)193 (23)196-(16)197 (16)208-(05)209 (00)232-(08)232 (23)232-(09)233 227-229,269-274
1985 100 none (19)041-(13)042 (23)062-(05)063 (20)140-(19)141 (07)182-(13)182 (15)274-(01)275 3-17
1986 100 none (15)130-(14)131 *(12)147-(13)148 (01)155-(07)155 (01)164-(12)164 (05)254-(20)254 (11)299-(23)299 (02)309-(12)309 85-86
1987 99 33-34 (18)139-(14)140 none
1988 100 none (14)245-(13)246 none
1989 96 90-99,202-204,206-209 (23)077-(13)078 (07)120-(14)120 (16)134-(14)135 (07)149-(14)149 (06)162-(13)162 (02)169-(14)169 (02)170-(15)170 (04)174-(16)174 (02)183-(13)183 (03)184-(14)184 (02)185-(15)185 (03)200-(12)200 (03)216-(19)216 (05)228-(13)228 (02)233-(13)233 (02)234-(09)234 (04)235-(11)235 (06)237-(13)237 (04)249-(15)249 (07)250-(14)250 (03)251-(13)251 (04)252-(15)252 (05)253-(14)253 (02)254-(14)254 (19)254-(02)255 (07)255-(14)255 (08)256-(17)256 (05)348-(13)348 none
1990 100 none *(11)143-(21)144 (03)164-(13)164 #(07)179-(24)180 #(04)357-(15)358 171-172,174-175
1991 100 none (18)001-(12)002 none
1992 100 none (15)245-(13)246 (21)338-(13)339 (18)339-(13)340 none
1993 100 none *(02)061-(11)063 (15)103-(01)104 (15)154-(13)155 (22)213-(06)214 none
1994 99 225-228 (17)092-(03)093 (22)129-(13)130 (19)152-(03)153 (22)160-(14)161 (19)245-(12)246 $(12)316-(06)319 none
1995 100 none $(03)001-(14)002 (17)175-(13)176 none
1996 100 none (21)102-(14)103 (07)117-(14)117 $(12)141-(21)142 $(12)331-(23)366 none
1997 100 none $(00)001-(23)026 (15)038-(13)039 (04)122-(13)122 $(00)150-(11)157 (18)234-(04)235 (17)261-(03)262 (05)262-(14)262 none
1998 100 none (18)119-(10)120 (16)131-(02)132 (00)312-(16)312 (00)314-(14)314 274-305