QUALITY ASSESSMENT OF SEA LEVEL DATA by the UH SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER JOINT ARCHIVE FOR SEA LEVEL Station : Las Palmas-B Latitude: 28 06.0N Country : Spain Longitude: 015 24.0W JASL # : 217B Time Meridian: GMT GLOSS # : 251 TOGA #: A024 NODC #: 72018501 Contributor : Instituto Espanol de Oceanografia C/ Corazon de Maria, No. 8 - 1 28002 Madrid SPAIN Originator : same Original Data: analog Instrmnt Type: A.OTT, float and stilling well Digitzd Intvl: one hour Present Data : Hourly, daily, and monthly values obtained by: Hourly : direct digitization, no filter 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 : 01 Jan 1971 - 17 May 1983 Gaps > 1 mon : 30 Jun 1971 - 04 Aug 1971;01 Jan 1973 - 01 Apr 1973 01 Apr 1974 - 31 Dec 1974;01 Mar 1975 - 16 May 1975 Time Refernce: GMT (00-23 hours) Space-filler Flag :-9999 Units : millimeters Missing Data Flag : 9999 Existing : Yes Operational : Yes Sat. Trans. : No Distribution : 1971-1982 Refernce Levl: The data have been linked to tide staff zero and fixed bench marks by the originators. Comment : The level stability of this record is questionable. A sharp downward trend is evident during 1971-73. No obvious step-function jumps could be identified in plots of hourly residuals and the decrease appears to be gradual for the most part. A level shift is suspected on 8 Feb 1983 (+8cm). Plots of differences with nearby sites indicate level uncertainty from May to Aug 1977 and from Dec 1980 to Feb 1983. Timing drifts of about 7 to 20 minutes occur off and on throughout the record as noted below. This record is separate from Las Palmas-A and Las Palmas-C due to very obvious large level shifts. CI MISSING REPLACED GAPS QUESTIONABLE YEAR (%) DATA OR BAD DATA FLUCTUATIONS ---- --- -------------------- --------------- -------------------- 1971 90 181-216 (13)064-(06)065 see comment above (05)095-(15)095 (00)234-(07)234 1972 100 none none see comment above 1973 75 1-91 none see comment above 1974 25 91-365 none see comment above 1975 79 60-136 (22)189-(05)190 see comment above (13)196-(20)196 1976 99 130-133 (21)102-(04)103 see comment above 1977 100 none (16)338-(23)338 see comment above 1978 98 87-94 none see comment above 1979 89 65-72,198-205, none see comment above 219-247 1980 93 282-309 none see comment above 1981 98 280-286 none see comment above 1982 100 none (00)018-(23)018 see comment above 1983 38 none (15)296-(03)297 see comment above