BODC FIXED STATION DOCUMENT NO. 57641 Site History : Durban, South Africa =================================== Station : Durban Country : South Africa GLOSS No : 013 Latitude : 029 52.0S Longitude : 031 03.0E Contributor : 1970-1987 TOGA Sea Level Center 1988-1994 South African Hydrographic Office Instrument Type : Float and stilling well gauge Location : In the tide gauge hut at the Tug Jetty (Small Craft Harbour) at the point Observational periods: 1954-1958, 1960-present Tide gauge benchmark (TGBM) description: Trig survey BM 4212 is at the east end of Salisbury Island. UTM Grid Reference 36 JUB 109930. Benchmark relationships: Tide Gauge Zero (TGZ) = South Africa Chart Datum TGZ = 0.838m below LLD (MSL) until 31 December 1978 TGZ = 0.900m below LLD (MSL) from 01 January 1979 TGZ = 0.904m below BM 4212 All heights have been referred to the station tide staff zero which is linked to fixed benchmarks. The original data were adjusted with levelling information provided by the contributors to the 1987 data as follows: period value added to ( (hour)day/month/year ) original (mm) ------------------------ --------------- *(00)30/09/70-(20)18/06/73 -100 (21)18/06/73-(23)13/05/75 -250 (00)14/05/75-(12)13/08/80 100 *(13)13/08/80-(23)30/03/81 -150 (00)31/03/81-(06)24/04/84 150 (07)24/04/84-(23)28/11/84 -320 *(00)29/11/84-(00)15/07/85 -120 *Correction of shift in reference level deduced from the plot of hourly residuals, daily and monthly means, and differences with the corrected monthly means of the Permanent Service for Mean Sea Level. There is a datum shift of -230mm after the 31st Dec 1987. All post 1987 data were received from the South African Hydrographic Office and reference to South Africa Chart Datum. Therefore there is a 230mm difference between these data and those previously adjusted by the TOGA Sea Level Center to the 1987 data. Quality Assessment: Comment: The timing of the gauge appears to be off by a fraction of an hour in some instances. Possible datum shift of approximately -50cm on 26 October 1992. Possible datum shift of approximately +35cm on 29 June 1993. Possible datum shift of approximately -20cm on 02 September 1994. Possible datum shift of approximately +20cm on 26 January 1996. NB: Timing shifted by + 2 hours 1997 142-174 CI QI MISSING REPLACED GAPS QUESTIONABLE YEAR (%) (%) DATA OR BAD DATA FLUCTUATIONS ---- --- --- ---------------- ---------------- ------------------ 1970 25 24 none none See comment above 1971 100 86 none (22)232-(21)233 " " " (22)236-(21)237 1972 100 84 none (22)072-(21)073 " " " 1973 98 84 141-149 (22)033-(21)034 " " " (22)217-(21)218 (22)223-(21)224 (22)229-(21)230 (22)234-(21)235 (22)239-(21)240 (22)246-(21)247 (22)250-(21)251 (22)256-(21)257 (22)262-(21)263 (23)281-(05)282 (23)282-(06)283 (22)288-(21)289 (22)324-(21)325 1974 73 68 42-127,238-246, (22)154-(21)155 " " " 259-262 1975 85 78 104-133 none " " " 1976 86 72 271-278,286-292, none " " " 309-320,327-335 1977 93 92 136-157 none " " " 1978 100 95 none none " " " 1979 91 82 148-155,162-164, none " " " 225-248 " " " 1980 100 98 none (12)196-(07)197 " " " 1981 50 48 89-138,194-327 (16)073-(03)074 " " " (16)074-(03)075 1982 100 97 none (14)221-(09)222 " " " 1983 98 80 172-175,328-332 none " " " 1984 87 70 47-51,63-79, (11)018-(18)018 " " " 161-163,310-335 (23)018-(08)019 (10)019-(19)019 (22)019-(20)020 (01)021-(08)021 (06)038-(00)039 (06)039-(05)040 1985 46 34 (09)201-(16)201 " " " (10)202-(16)202 1986 78 62 99-105,118-119, (06)117-(22)117 " " " 168-184,252-259, (04)323-(21)323 270-287,295-301, (05)326-(18)326 320-322,336-358 (05)327-(17)327 1987 83 66 66-68,90-105, (06)020-(13)020 " " " 160-167,269-279, (07)268-(09)268 321-329,349-363 1988 30 25 22,23,24,25,42- none 64-69,92-98,207- 48,59-61,71-82, 208,215-217,241- 98-137,150,151- 245 153,159-187,249- 300,355-366 1989 85 85 25-26,72-73,128- none See comment above 132,170-192,286- 298,351-363 1990 50 45 43-46,47,48,49, none 1-3,9-18,207-208, 50-60,67-199,226 337-339,350-351, -260 364-365 1991 78 65 61-62,62-63,64- none 1-7,42-51,56-61, 65,67-77,85-87, 77-85,87-105 105-116,167-211, 221-222,223-224, 287-294,299,325- 329 1992 80 76 50-51,104-153, none 9-13,49-50,160- 167-174,181-184, 167,295-296,302 198-202,244,251, 292-293,296-300 1993 87 66-68,133,134- none See comment above 152,169-170,170- 171,171-172,172- 173,184-187,187- 188,194,201-207, 211-222,235,272, 302 1994 58 7,31,84-98,122- none See comment above 172,202-245,251- 256,259-263,272- 276,280-286,290- 298,311-319,357- 365 1995 76 26-30,90-91,125- none 15-19,91-93,122- 129,132-142,156- 125,160-162 158,162-198,244- 254,282-290,317- 321,365 1996 85 14-16,24-26,40- none 62-64,90-91,150, 43,92-95,158-172 152-158,169-170, 277-281,285-288, 212-213,266 323-326,346-352, 354-366 1997 61 1-142 see note above 2000 75 1-44,222-223, none See comment above 318-366 BODC FIXED STATION DOCUMENT NO. 58142 Applies to BODC Series Ref. Nos.: 529558, 579555 QUALITY ASSESSMENT OF SEA LEVEL DATA by the TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER JOINT ARCHIVE FOR SEA LEVEL Station : Durban Latitude: 29 53.0S Country : South Africa Longitude: 031 00.0E JASL # : 181A Time Meridian: 030E (GMT + 2 hr) GLOSS # : 013 TOGA #: I012 NODC #: 32039101 Contributor : Directorate of Hydrography Maritime Headquarters Private Bag Retreat 7965 South Africa Originator : same Original Data: analog Instrmnt Type: Float and stilling well type, Kent Digitzd Intvl: hourly Present Data : Hourly, daily, and monthly values obtained by: Hourly : manually filtered raw data Daily : 119-point convolution filter (Bloomfield, 1976) centered on noon applied to the hourly data with respective periods of the 95, 50, and 5% amplitude points at 124.0, 60.2, and 40.2 hours Monthly: Simple average of all daily values; calculated if 7 or fewer days are missing Span of data : 30 Sep 1970 - 31 Dec 1987 Gaps > 1 mon : 11 Feb - 07 May 1974; 30 Mar - 18 May 1981; 13 Jul - 23 Nov 1981; 31 Dec 1984 - 16 Jul 1985 Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 Units : millimetres Missing Data Flag :99999 Refernce Levl: All heights have been referred to the station tide staff zero which is linked to fixed bench marks. The original data were adjusted at JASL with leveling information provided by the contributors to the 1987 data as follows: period value added to ( (hour)day/month/year ) original (mm) ------------------------ --------------- *(00)30/09/70-(20)18/06/73 -100 (21)18/06/73-(23)13/05/75 -250 (00)14/05/75-(12)13/08/80 100 *(13)13/08/80-(23)30/03/81 -150 (00)31/03/81-(06)24/04/84 150 (07)24/04/84-(23)28/11/84 -320 *(00)29/11/84-(00)15/07/85 -120 *Correction of shift in reference level deduced from the plot of hourly residuals, daily and monthly means, and differences with the corrected monthly means of the Permanent Service for Mean Sea Level.