QUALITY ASSESSMENT OF SEA LEVEL DATA by the UH SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER JOINT ARCHIVE FOR SEA LEVEL updated: 20 May 2011 Station : Dumont d'Urville Latitude: 66 39.7S Country : France Longitude: 140 00.6E JASL # : 189A Time Meridian: 135E (GMT + 9 hr) GLOSS # : 131 Originator #: NODC #: 36146001 Contributor : Service d'Observation ROSAME, LEGOS/OMP 14 Ave. Edouard Belin 31400 Toulouse FRANCE Originator : same Original Data: digital Instrmnt Type: Mors (bottom-mounted pressure gauge). The gauge is a MORS automatic tide gauge station which activates every half hour with measurements of atmospheric pressure and air temperature with a Mors sensor and bottom pressure and sea water temperture with an immersed Mors sensor, which consists of a ventilated ParoScientific pressure sensor at the base of a stilling well which is used to filter waves. The ventilation of the sensor results in a measurement of the total pressure (atmosphere + ocean) minus the atmosphere; hence, a direct measure of sea level, assuming water density is properly estimated. These data have not been corrected for the inverted barometer effect. Digitzd Intvl: 30 minutes Present Data : Hourly, daily, and monthly values obtained by: Hourly : Four minute integration time is used for the bottom pressure measurement. Data are recorded on the in-board memory every 30 minutes. Data are transmitted via ARGOSS every 30 minutes to Toulouse. The data are then processed to decrypt the messages and compute sea level based on i) relative bottom pressure, ii) water temperature, and iii) barometric pressure. From this set of data in combination with salinity, which is periodically measured but is assumed to be constant over extended periods, one computes water density based on the UNESCO formula for the sea-water equation; thus, the sea level is deduced and an hourly sub-sample is extracted. 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 : 16 Jan 2008 - 19 Aug 2010 Gaps > 1 mon : 11 Jun 2010 - 12 Aug 2010 Time Refernce: GMT (00-23 hours) Space-filler Flag :-9999 Units : millimeters Missing Data Flag : 9999 Existing : Yes Operational : Yes Sat. Trans. : Yes Distribution : 2008-2010 Refernce Levl: Presently no link is established between the tide gauge and fixed bench marks. Please refer to the originator for the up-to-date status. Comment : The plot of the hourly data minus the predicted tides reveals data with excellent timing characteristics and no obviously erroneous data. CI MISSING REPLACED GAPS QUESTIONABLE YEAR (%) DATA OR BAD DATA FLUCTUATIONS ---- --- -------------------- --------------- -------------------- 2008 96 none none none 2009 100 none none none 2010 46 162-224,226-229 none none