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 1959-2008

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:

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 ASLVBG01 161,353-354 239-240    
  ASLVBG02 161,353-354 001-122,124-161,161-195,239-242 99 15 minutes
  ASLVBH01 161,353-354 None    
  EWDASS01 161,353-354 001-161,161-195,318    
  EWSBSS01 161,353-354 001-161,161-195,239-240,318    
2008 ASLVBG01,ASLVBG02,ASLVBH01 282-283,357 None 99 15 minutes
  EWDASS01 282-283,357 016    
  EWSBSS01 282-283,357 016,153-163    
2009 ASLVBG02 346,356-358 None 99 15 minutes