Durban (South Africa) Data Quality Assessment

Quality Assessment of sea level data by the TOGA Sea Level Center/National Oceanographic Data Centre Joint Archive for Sea Level

Station Durban Latitude 29° 53.0' S
Country South Africa Longitude 031° 00.0' E
JASL # 181A Time Meridian 030° E (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
Instrument Type: Float and stilling well type, Kent
Digitized Interval: Hourly
Present Data: Hourly, daily, and monthly values obtained by:
Hourly: Manually filtered raw data
Daily: 119-point convolution filter (Bloomfield, 1976) centred 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 September 1970 - 31 December 1987
Gaps > 1 Month: 11 February - 07 May 1974; 30 March - 18 May 1981; 13 July - 23 November 1981; 31 December 1984 - 16 July 1985
Time Reference: GMT (hours 00-23)
Space-filler Flag: -9999
Units: Millimetres
Missing Data Flag: 99999
Reference Level: 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 levelling information provided by the contributors to the 1987 data as follows:
Period ((hour)day/month/year) Value added to 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.