Holyhead site history
History summary
| Station name | Holyhead |
|---|---|
| Country | UK |
| Latitude of measuring points |
1978 onwards: 53° 18' 50.2" N
Prior to 1978: 53° 18' 28" N |
| Longitude of measuring points |
1978 onwards: 04° 37' 13.6" W
Prior to 1978: 04° 37' 52" W |
| OS grid ref. of measuring points |
1978 onwards: SH 2553 8287
Prior to 1978: SH 2479 8221 |
| Datum reference |
All data refer to Admiralty Chart Datum (ACD)
ACD = ODN -3.05m |
| Time reference | GMT (hours 00-23) |
| Contributor |
Environment Agency Anglian Regional Office,
Kingfisher House, Goldhay Way, Orton Goldhay, Peterborough, Cambridgeshire, PE2 5ZR |
| Instrument type |
1958 to 1977 - Lea gauge.
1978 to 1984 - Gauge relocated. Two stilling wells with Munro and Ott recorder. 1984 - DATARING system installed. The primary gauge is a bubbler gauge and the backup gauge is a Munro float gauge. |
| Site of measuring points | The tide gauge building and measuring points are attached to the jetty face directly below Tide Gauge building. |
| Position of tide gauge building | SH 2553 8287 - Brick Tide Gauge building S side Salt Island Jetty, adjacent to Lighthouse |
| Observational period | 1964 - 1969, 1981,1983,1985,1988,1990 - 1991, 1995 - 2026 |
Benchmark descriptions
| Benchmark | OS grid ref. | Description | Height above ODN (m) |
|---|---|---|---|
| TGBM | SH 2553 8287 | Bolt on concrete foundation, N side of tide gauge building. | 4.386 |
| Aux1 | SH 2556 8289 | Cut mark on harbour lighthouse S face | 5.515 |
| Aux2 | N/A | DESTROYED | N/A |
| Aux3 | SH 2510 8296 | Bolt on N face Salt Island Bridge | 4.564 |
| BM | SH 2520 8296 | Cut mark SW corner Customs House | 5.286 |
ODN = Ordnance Datum Newlyn
Parameters
Please Note: All parameters listed below are sea level measured in metres. Different parameter codes represent different gauges. For an explanation of the codes, please see the BODC parameter dictionary.
| Period | Parameters | Completeness index (%) | Sample interval |
|---|---|---|---|
| 1964 | ASLVZZ01 | 95 | 60 minutes |
| 1965 | ASLVZZ01 | 99 | 60 minutes |
| 1966 | ASLVZZ01 | 100 | 60 minutes |
| 1967 | ASLVZZ01 | 100 | 60 minutes |
| 1968 | ASLVZZ01 | 96 | 60 minutes |
| 1969 | ASLVZZ01 | 99 | 60 minutes |
| 1970 | ASLVZZ01 | 99 | 60 minutes |
| 1971 | ASLVZZ01 | 94 | 60 minutes |
| 1972 | ASLVZZ01 | 7 | 60 minutes |
| 1973 | ASLVZZ01 | 35 | 60 minutes |
| 1977 | ASLVZZ01 | 4 | 60 minutes |
| 1978 | ASLVZZ01 | 34 | 60 minutes |
| 1979 | ASLVZZ01 | 61 | 60 minutes |
| 1980 | ASLVZZ01 | 95 | 60 minutes |
| 1981 | ASLVZZ01 | 100 | 60 minutes |
| 1982 | ASLVZZ01 | 100 | 60 minutes |
| 1983 | ASLVZZ01 | 98 | 60 minutes |
| 1984 |
ASLVZZ01 ASLVBG02 |
48 (January to August) 50 (August to December) |
60 minutes |
| 1985 | ASLVBG02 | 100 | 60 minutes |
| 1987 | ASLVBG02 | 93 | 60 minutes |
| 1988 | ASLVBG02 | 100 | 60 minutes |
| 1989 | ASLVBG02 | 93 | 60 minutes |
| 1990 | ASLVBG02 | 99 | 60 minutes |
| 1991 | ASLVBG02 | 77 | 60 minutes |
| 1995 | ASLVBG02 | 88 | 15 minutes |
| 1996 | ASLVBG02 | 100 | 15 minutes |
| 1997 | ASLVBG02 | 99 | 15 minutes |
| 1998 | ASLVBG01 | 100 | 15 minutes |
| 1999 | ASLVBG02 | 99 | 15 minutes |
| 2000 | ASLVBG02 | 98 | 15 minutes |
| 2001 | ASLVBG02 | 100 | 15 minutes |
| 2002 | ASLVBG02 | 96 | 15 minutes |
| 2003 | ASLVBG02 | 98 | 15 minutes |
| 2004 | ASLVBG02 | 99 | 15 minutes |
| 2005 | ASLVBG02 | 88 | 15 minutes |
| 2006 | ASLVBG02 | 98 | 15 minutes |
| 2007 | ASLVBG02 | 92 | 15 minutes |
| 2008 | ASLVBG02 | 94 | 15 minutes |
| 2009 | ASLVBG02 | 99 | 15 minutes |
| 2010 | ASLVBG02 | 96 | 15 minutes |
| 2011 | ASLVBG02 | 99 | 15 minutes |
| 2012 | ASLVBG02 | 99 | 15 minutes |
| 2013 | ASLVBG02 | 100 | 15 minutes |
| 2014 | ASLVBG02 | 100 | 15 minutes |
| 2015 | ASLVBG02 | 100 | 15 minutes |
| 2016 | ASLVBG02 | 100 | 15 minutes |
| 2017 | ASLVBG02 | 100 | 15 minutes |
| 2018 | ASLVBG02 | 100 | 15 minutes |
| 2019 | ASLVBG02 | 100 | 15 minutes |
| 2020 | ASLVBG02 | 100 | 15 minutes |
| 2021 | ASLVBG02 | 100 | 15 minutes |
| 2022 | ASLVBG02 | 99 | 15 minutes |
| 2023 | ASLVBG02 | 93 | 15 minutes |
| 2024 | ASLVBG02 | January - December | 15 minutes |
| 2025 |
ASLVBG02
ASLVBG01 |
January - August
September - December |
15 minutes |
| 2026 | ASLVBG01 | January - May | 15 minutes |
Quality assessment
All data have been compared with the current Harmonic Constants library, and residuals checked. Records have been visually inspected for spikes, datum shifts and timing errors.
Where there are problems with the primary channel, data may be available from the backup channel. Please contact enquiries@bodc.ac.uk for more information.
In August 1984 the DATARING system was installed. The bubbler gauge (ASLVBG02) replaced the Munro gauge (ASLVZZ01). There is a gap in the file where the gauge was changed.
In 1998, the primary channel (ASLVBG02) was out of order for the entire year, so the backup channel (ASLVBG01) has been outputted instead.
February 2003 - File output has been altered so that all values fall on the quarter hour and gaps are filled in with null values, marked with an 'N' flag.
March 2003 - Residuals (observed minus predicted sea level values, measured in metres) now included in the file output.
On 31/10/2011 a new data logger was installed. Tests were carried out to ensure the logger was functioning correctly, resulting in some data being lost.
November 2012 - The file output has been altered to reflect the Contributor name change from Proudman Oceanographic Laboratory to National Oceanography Centre, Liverpool. Also, the Parameter
code has been improved and now uses a controlled vocabulary.
Missing and suspect data have been reported on the following day numbers:-
| Period | Parameter | Missing data | Suspect data |
|---|---|---|---|
| 1964 | ASLVZZ01 | 003,096-100,227-231,291-292,360-364 | 045-051,100-106,128-135,265-269,295-299 |
| 1965 | ASLVZZ01 | 221-222 | 063-071,218-222,327-338 |
| 1966 | ASLVZZ01 | None | 027-028,055-060,283-291,315-320 |
| 1967 | ASLVZZ01 | None | 084-088,111-114,223-230 |
| 1968 | ASLVZZ01 | 010-011,197-198,226-227,263-264,273-276,333 | 174-180,298-302,359-364 |
| 1969 | ASLVZZ01 | 043-044 | 096-099,360-365 |
| 1970 | ASLVZZ01 | 050-051 | 001,067-073,126-131,139-146,199-203,242-250,312-318 |
| 1971 | ASLVZZ01 | 092-095,190,218-221,254-256,287,335-336,357-364 | 011-017,036-043,056-061,111-116,130-135,177-190,204-218,232-239,283-286 |
| 1972 | ASLVZZ01 | 025-366 | None |
| 1973 | ASLVZZ01 | 001-152,180-187,208-215,229-236,270-271,283-284,291-298,312-365 | 177-180,203-208,223-229,236-246,254-267,271-275,284-286,308-312 |
| 1977 | ASLVZZ01 | 001-311,325-365 | None |
| 1978 | ASLVZZ01 | 001-208,277-282,338-365 | 313 |
| 1979 | ASLVZZ01 | 001-136,326-327,361-365 | None |
| 1980 | ASLVZZ01 | 001-009,116-127 | None |
| 1981 | ASLVZZ01 | None | None |
| 1982 | ASLVZZ01 | None | None |
| 1983 | ASLVZZ01 | 294-301 | 058-062,321-327 |
| 1984 |
ASLVZZ01 ASLVBG02 |
054-055,108-111,132-135,185-235 None |
None None |
| 1985 | ASLVBG02 | None | None |
| 1987 | ASLVBG02 | 143-168 | None |
| 1988 | ASLVBG02 | None | None |
| 1989 | ASLVBG02 | 090-114,327-328,340-341,344-345 | None |
| 1990 | ASLVBG02 | 067-068 | None |
| 1991 | ASLVBG02 | 280-365 | None |
| 1995 | ASLVBG02 | 001-033,137-145 | None |
| 1996 | ASLVBG02 | None | None |
| 1997 | ASLVBG02 | 107-108,140-141 | 336-346,351-365 |
| 1998 | ASLVBG01 | None | None |
| 1999 | ASLVBG02 | 089,145-146,236 | 001-042 |
| 2000 | ASLVBG02 | 060,109,137-138,348 | 200 |
| 2001 | ASLVBG02 | None | None |
| 2002 | ASLVBG02 | 295-311 | None |
| 2003 | ASLVBG02 | 106,224-225,239,357-358 | None |
| 2004 | ASLVBG02 | 041,083 | None |
| 2005 | ASLVBG02 | 089-101,103-109,194-209,334,337-347 | 068-089,101-103,250 |
| 2006 | ASLVBG02 | 060,069-075,081-082,144 | None |
| 2007 | ASLVBG02 | 199-212,213-230 | None |
| 2008 | ASLVBG02 | 058-059,070-071,225-226,232,240-249,261-263,357 | 226-232 |
| 2009 | ASLVBG02 | 147-148 | 159-218 |
| 2010 | ASLVBG02 | 055,144-145,160-161,238-239,239-244 | 015,044-045,106-160,161-194,239,243,300-365 |
| 2011 | ASLVBG02 | 012-013,290 | 009-010,044,078,094,137-138,194,208,222,236,243,250-290,290-365 |
| 2012 | ASLVBG02 | 031,091 | 001-031,031-081,081-174,304,334 |
| 2013 | ASLVBG02 | None | 162 |
| 2014 | ASLVBG02 | None | 003,225-230,274-285 |
| 2015 | ASLVBG02 | None | 043-067,069-112,120-136,159,177-183,268,270-271,273,284-300,311-319,340-358 |
| 2016 | ASLVBG02 | None | 019,048,050-053,062-064,069,074-075,087-088,097-102,105-109,117-125,167,170-179,182,322-323,326 |
| 2017 | ASLVBG02 | None | 006,009-010,033-034,037,054-057,059,076-080,135-136,172-179,184-190,194-204,210-221,223-231,233-266,274-282,301-310,313-317,331-365 |
| 2018 | ASLVBG02 | None | 001-003,005-012,026-033,035-038,045-048,050,056-063,068-069,073-075,077-082,085-088,090-096,099-101,104-108,110,112-117,121,123,125,127-131,139,146 |
| 2019 | ASLVBG02 | None | 075,117,134-139,155 |
| 2020 | ASLVBG02 | None | 060,121-127,151-157,162,171-177,182-200,226-253,255,257-268,271-283,288-312,315-327,329-340,342-366 |
| 2021 | ASLVBG02 | None | 007,009-035,039-051,054-055,058-063,068-075,084-091,116-124,129-130,144-150,160-168,171,172-182,187,193-196,204-211,217-226,232-235,237-239,249-255,261-268,277-283,290-295,304-305,308-311,337-338,340-342 |
| 2022 | ASLVBG02 | 060,322 | 002-003,005-008,034-035,049-052,173-259,268-275,278-289,296-307,309-315,319,322 |
| 2023 | ASLVBG02 | 200-206,230,243,254,255,301-320 | 021-024,043-045,067-069,077-096,101-112,163-199,241-243,255,320 |
| 2024 | ASLVBG02 | 070,333 | 013,096,146-150,158,167-175,184-198,236,256-259,274-333,333-366 |
| 2025 |
ASLVBG02
ASLVBG01 |
004,066,094-097,202,225,228
280,294,358 |
001-004,004-035,037-044,046-048,050,053-054,067-068,070-071,108-109,130,137-138,147,188
257,260,264-266,269,290,305,307-308,311,313-317,319-321,323-324,326-331,334,359 |
| 2026 | ASLVBG01 | 007,018,063,090,091,096,099-100,108,135 | 002,007,009-010,013-018,018-022,024,027-053,055-056,061-063,063-073,075-082,084-090,098-135,135-151 |
