Lerwick (Shetland Isles) Site History
History Summary
| Station name | Lerwick (Shetland Isles) |
|---|---|
| Country | U.K. |
| Latitude of measuring point | 60° 09' 14.5" N |
| Longitude of measuring point | 01° 08' 25.1" W |
| OS grid ref. of measuring point | HU 4783 4137 |
| Datum reference | All data refer to Admiralty Chart Datum (ACD) |
| Time reference | GMT (hours 00-23) |
| Contributor | Tide Gauge Inspectorate (TGI), Proudman Oceanographic Laboratory, Joseph Proudman Building, 6 Brownlow Street, Liverpool, L3 5DA, U.K. |
| Instrument type | 1956: Temporary Munro gauge installed by National Institute of Oceanography. 1963: Lea vertical gauge installed. 1965: Temporary Munro gauge removed. 1988: DATARING system installed. 1995: Lea gauge replaced by an Ott pneumatic gauge. 1995: Mid tide bubbler installed (30/11/95). |
| Site of measuring point | The measuring points are fastened to the harbour wall below the T.G. Building |
| Position of tide gauge building | HU 4783 4137 - GRP building at entrance to small boat harbour |
| Observational period | 1959-2006 |
Benchmark descriptions
| Benchmark | OS grid ref. | Description | Height above ODL (m) |
|---|---|---|---|
| TGBM | HU 4783 4129 | OSBM bolt breakwater wall | 3.350 |
| Aux1 | HU 4784 4125 | Queens Hotel, 7.5m SW face S angle | 4.008 |
| Aux2 | HU 4777 4110 | Lerwick Parish Church, N face NW angle | 22.275 |
| Aux3 | N/A | No details at present | N/A |
ODL = Ordnance Datum Local
Datum Information
Also see document 83204
All data now refer to Admiralty Chart Datum (ACD). The following years have been altered (see table below).
| Period | Correction Applied (m) |
|---|---|
| 1959-1964 | +0.305 |
| 1965 | +0.306 |
| 1966-1973 | +0.305 |
| 1974-1979 | +0.306 |
| 1986-1988 | -3 |
1988-2002 Tide Gauge Zero (TGZ) = Admiralty Chart Datum (ACD)
TGZ = 2.71m below Ordnance Datum Newlyn
Quality Assessment
Hourly heights reduced from Lea gauge loaned by the Harbour Master. All datum values refer to local Ordnance Datum.
The tide gauge was destroyed by fire in February 2002. Refurbishment was completed in August 2003.
Gaps in the Data Record
The following gaps occur in the data set.
| Start | End | Reason |
|---|---|---|
| 1900h 10 Mar 1974 | 2300h 15 Mar 1974 | |
| 2000h 19 Mar 1974 | 0800h 25 Mar 1974 | |
| 1100h 13 Apr 1974 | 1000h 14 Apr 1974 | |
| 0500h 16 Apr 1974 | 0800h 17 Apr 1974 | |
| 1100h 23 Apr 1974 | 0800h 24 Apr 1974 | |
| 0900h 30 Apr 1974 | 0800h 01 May 1974 | |
| 0900h 21 May 1974 | 0900h 27 May 1974 | |
| 1100h 20 Nov 1974 | 1300h 21 Nov 1974 | |
| 0600h 24 Jan 1975 | 0900h 25 Jan 1975 | Clock stopped |
| 1000h 17 Jan 1976 | 1300h 19 Jan 1976 | Ink ran out |
| 1000h 15 Mar 1976 | 0800h 16 Mar 1976 | Pen off chart |
| 1700h 17 Apr 1977 | 0800h 18 Apr 1977 | |
| 0900h 25 Apr 1977 | 0800h 26 Apr 1977 | |
| 0000h 04 Jun 1977 | 0800h 06 Jun 1977 | |
| 0900h 08 Aug 1977 | 0800h 29 Aug 1977 | |
| 1400h 10 Sep 1977 | 1600h 11 Sep 1977 | |
| 1800h 13 Nov 1977 | 0900h 14 Nov 1977 | |
| 1500h 09 Dec 1977 | 0900h 10 Dec 1977 | |
| 1000h 18 Dec 1977 | 0900h 19 Dec 1977 | |
| 0000h 05 May 1980 | 0800h 05 May 1980 | |
| 0000h 15 May 1980 | 0800h 15 May 1980 | |
| 0000h 18 May 1980 | 0800h 18 May 1980 | |
| 2300h 30 Jul 1980 | 0600h 31 Jul 1980 | |
| 0000h 17 Apr 1980 | 0900h 17 Apr 1980 | Interpolated by hand |
| 0000h 19 Apr 1980 | 0900h 19 Apr 1980 | Interpolated by hand |
| 0000h 22 Apr 1980 | 0800h 19 Apr 1980 | Pen not working |
| 0100h 14 Feb 1982 | 0900h 15 Feb 1982 | Ink ran out |
| 1200h 18 Nov 1986 | 2300h 18 Nov 1986 | |
| 1000h 08 Dec 1986 | 0900h 15 Dec 1986 | |
| 0400h 27 Aug 1990 | 1400h 31 Aug 1990 |
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:
- ASLVZZ01 = Float gauge, Sea level (metres)
- ASLVBG01 = Bubbler, Sea Level (metres)
- ASLVBG02 = Bubbler, Sea Level (metres)
- ASLVBH01 = Bubbler, Half tide (metres)
Please note : Completeness index has been calculated for the primary channel only. Where multiple channels are available, ASLVBG02 is the primary channel.
| Period | Parameter | Missing data | Suspect data | Completeness index (%) | Sample interval |
|---|---|---|---|---|---|
| 1959 | ASLVZZ01 | None | 051,138-144 | 100 | 60 minutes |
| 1960 | ASLVZZ01 | None | None | 100 | 60 minutes |
| 1961 | ASLVZZ01 | None | None | 100 | 60 minutes |
| 1962 | ASLVZZ01 | None | None | 100 | 60 minutes |
| 1963 | ASLVZZ01 | None | 059-063 | 100 | 60 minutes |
| 1964 | ASLVZZ01 | None | 251-254 | 100 | 60 minutes |
| 1965 | ASLVZZ01 | None | 239-242,262-263 | 100 | 60 minutes |
| 1966 | ASLVZZ01 | None | 074-075,080-084,091-101,133,311,321 | 100 | 60 minutes |
| 1967 | ASLVZZ01 | None | 222-240,269-270,305-310 | 100 | 60 minutes |
| 1968 | ASLVZZ01 | 017-018,289-290,364 | None | 99 | 60 minutes |
| 1969 | ASLVZZ01 | 001-013,068-069,182-202,334-336 | 015-021,120-126,264-267,271-272 | 90 | 60 minutes |
| 1970 | ASLVZZ01 | None | 021-022,150-173 | 100 | 60 minutes |
| 1971 | ASLVZZ01 | None | None | 100 | 60 minutes |
| 1972 | ASLVZZ01 | 211-212 | 018,064-065,071,101-108,134-135,292-297 | 99 | 60 minutes |
| 1973 | ASLVZZ01 | 338-340,363 | 106-108,153-157,165-170,184,194-201,237-245,282-290,296-300,312-314 | 99 | 60 minutes |
| 1974 | ASLVZZ01 | 069-074,078-084,103-104,106-107,113-114,120-121,141-147,324-325 | 059,093-099,117-120,150-154,172-174 | 92 | 60 minutes |
| 1975 | ASLVZZ01 | 024-025,346-347 | 089,117-118,156-157,178,242,346 | 99 | 60 minutes |
| 1976 | ASLVZZ01 | 001-005,017-019,075-076 | 010,055,061,158,353-362 | 97 | 60 minutes |
| 1977 | ASLVZZ01 | 107-108,115-116,155-157,220-241,253-254,317-318,343-344,352-353 | 036-038,042-050,122-126,153-154,157-159,164-165,168-172,181-185,260-268,309,314,326-331,353-365 | 90 | 60 minutes |
| 1978 | ASLVZZ01 | 021-023,079-094,243-249,346-348 | 001-002,054-055,060-062,065-068,114-115,170-172,259-260,325-332 | 93 | 60 minutes |
| 1979 | ASLVZZ01 | 144-145,196-197,299-301 | 056-060,086-093,145-147,219-220 | 98 | 60 minutes |
| 1980 | ASLVZZ01 | None | 110-112,245-247 | 100 | 60 minutes |
| 1981 | ASLVZZ01 | None | 013,027,029,071,073,102,105,117,131-132,175,273 | 100 | 60 minutes |
| 1982 | ASLVZZ01 | 045-046 | 015,019,076,094-095,104-105,108-109,156,195-197,356 | 99 | 60 minutes |
| 1983 | ASLVZZ01 | None | 070,151-152,210,212,287-288,305 | 100 | 60 minutes |
| 1984 | ASLVZZ01 | None | 036,148,151,231,274 | 100 | 60 minutes |
| 1985 | ASLVZZ01 | None | 031,087,116-118,147-148,205,220-222,225,249,251-253,350,354 | 100 | 60 minutes |
| 1986 | ASLVZZ01 | 322-323,342-349 | 005-006,015-016,018-021,025,079-080,120 | 98 | 60 minutes |
| 1987 | ASLVZZ01 | None | 037-039,094-095,097-098,155,173,245,247,284,289-290 | 100 | 60 minutes |
| 1988 | ASLVZZ01 | None | 007,044-045,071,085-086,090,113,149,186,203,278,336 | 100 | 60 minutes |
| 1989 | ASLVZZ01,ASLVBG02 | 001-137 | None | 63 | 60 minutes |
| 1990 | ASLVBG02 | 239-243 | None | 99 | 60 minutes |
| 1991 | ASLVBG02 | None | None | 100 | 60 minutes |
| 1992 | ASLVBG02 | None | None | 100 | 60 minutes |
| 1993 | ASLVBG01 | 121-151 | None | ||
| ASLVBG02 | None | None | 100 | 15 minutes | |
| 1994 | ASLVBG01,ASLVBG02 | None | None | 100 | 15 minutes |
| 1995 | ASLVBG01 | 333-334 | 079-080 | ||
| ASLVBG02 | 333-334 | None | 99 | 15 minutes | |
| ASLVBH01 | 001-334 | None | |||
| 1996 | ASLVBG01,ASLVBG02,ASLVBH01 | 065-076 | None | 97 | 15 minutes |
| 1997 | ASLVBG01,ASLVBH01 | None | None | ||
| ASLVBG02 | None | 332 | 100 | 15 minutes | |
| 1998 | ASLVBG01,ASLVBH01 | None | None | ||
| ASLVBG02 | None | 225-307 | 100 | 15 minutes | |
| 1999 | ASLVBG01,ASLVBH01 | None | None | ||
| ASLVBG02 | None | 116-156,236-242,244-249 250,251,324-327 | 100 | 15 minutes | |
| 2000 | ASLVBG01,ASLVBH01 | 060 | None | ||
| ASLVBG02 | 060 | 056-058,060-067,128,129-132 175,176,191,196-223,228-277 280-366 | 99 | 15 minutes | |
| 2001 | ASLVBG01,ASLVBH01 | None | None | ||
| ASLVBG02 | None | 001-110,147-149,155-159,163-167,169-341,346-365 | 100 | 15 minutes | |
| 2002 | ASLVBG01 | 043,050-365 | 008-013,023,046-050 | ||
| ASLVBG02 | 050-365 | 001-050 | 14 | 15 minutes | |
| ASLVBH01 | 050-365 | 023 | |||
| 2003 | ASLVBG01 | 001-216,280 | 265-280,348-349,354-356 | ||
| ASLVBG02,ASLVBH01,EWDASS01,EWSBSS01 | 001-216,280 | None | 40 (Off network until August) | 15 minutes | |
| 2004 | ASLVBG01 | 064,105-106 | 026-029,039-040,052-057,352-354 | ||
| ASLVBG02,ASLVBH01 | 064,105-106 | None | 99 | 15 minutes | |
| EWDASS01 | 027,064,105-106 | None | |||
| EWSBSS01 | 027,064,105-106,217 | Channel appears to stick frequently | |||
| 2005 | ASLVBG01 | 159-160 | 021-024,044-045,049-055,057-058,062-064,066-073,097-098 | ||
| ASLVBG02,ASLVBH01 | 159-160 | None | 99 | 15 minutes | |
| EWDASS01,EWSBSS01 | 159-160 | 040,061,082,123,243,278 | |||
| 2006 | ASLVBG01,ASLVBH01 | 109-110,144,284-285,354-355 | None | ||
| ASLVBG02 | 109-110,144,284-285,354-355 | 304-321,335-354,355-365 | 99 | 15 minutes | |
| EWDASS01 | 060,109-110,144,284-285,304-365 | 228-284,285-304 | |||
| EWSBSS01 | 109-110,144,284-285,304-365 | 004,060,228-284,285-304 | |||
| 2007 | ASLVBG02 | 161,353-354 | 001-122,124-161,161-195,239-242 | 99 | 15 minutes |
| 2008 | ASLVBG02 | 282-283,357 | None | 99 | 15 minutes |
| 2009 | ASLVBG02 | 346,356-358 | None | 99 | 15 minutes |
