QUALITY ASSESSMENT OF SEA LEVEL DATA by the UH SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER JOINT ARCHIVE FOR SEA LEVEL updated: 27 Apr 2010 Station : Davao-A Latitude: 07 07.3N Country : Philippines Longitude: 125 39.8E JASL # : 372A Time Meridian: 120E (GMT + 8 hr) GLOSS # : 071 TOGA #: P009 NODC #: 10127501 Contributor : National Mapping Resource Information Authority Coast and Geodetic Survey Department 421 Barraca St. San Nicolas 1010 Manila, Philippines Originator : same Original Data: analog Instrmnt Type: A.OTT, gravity type Digitzd Intvl: one hour Present Data : Hourly, daily, and monthly values obtained by: Hourly : The original digitizing interval was hourly 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 1984 - 31 Jul 1997 Gaps > 1 mon : 31 Aug 1993 - 10 Nov 1993;30 Jun 1995 - 01 Apr 1996 Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 Units : millimeters Missing Data Flag : 9999 Existing : Yes Operational : Yes Sat. Trans. : No Distribution : 1984-1997 Refernce Levl: All data are referred to a historic fixed bench mark (1951). The series is broken into Davao-A and Davao-B since there is an apparent change to the mean level between the segments. Also, the timing appears off by roughly 12 minutes in Davao-B relative to Davao-A. Comment : A suspicious signature exists in 1986. It appears from the daily averages to be a reference level shift of about 20 cm on 30 Nov. A similar feature of less magnitude exists at the same time for Jolo and Legaspi; thus the possibility of the suspicious signature being real exists. The originators have confirmed that no errors were obvious in the analog chart or processing. The numerous questionable fluctuations below may be a result of inaccurate timing of the gauge and/or from the tidal analysis not being able to resolve certain harmonics. Typhoon activity did not pass near. CI MISSING REPLACED GAPS QUESTIONABLE YEAR (%) DATA OR BAD DATA FLUCTUATIONS ---- --- -------------------- --------------- -------------------- 1984 100 none none 122-123,149-151,181- 182,203,219-220,322 1985 100 none none 10-11,20-22,53-55, 62,79,81-86,136,152- 154,165-166,201-202, 211-218,257-258,271- 272,276-277,312-313, 318,326-331,341-342, 359 1986 100 none (00)125-(11)125 10-13,17-19,54-55, (22)277-(13)278 68-70,72-73,100,123, 131,168-173,176-177, 203-209,245-251,259- 268,273-276,278-282, 287-297,305-310,332- 337,342-349,352-355, 363-365 1987 99 339-341 none 1-6,47-50,57-67,75- 77,113-117,129-131, 138-145,172-173,178- 180,182-183,205-216, 224-225,231,238-244, 251-256,262-270,274- 281,287,294-297,300- 309,314-316 1988 100 none none 3-6,19-24,31,38,47- 54,60-64,113-116, 162-163,165-166,168- 169,187,207-212,214, 241-244,355-357,359- 363,365 1989 100 none none 7,9,11-12,26-27,29- 30,154,183-184,212, 214-215,226-227,286- 287,328-329,337-338 1990 98 86-90,132-136 none none 1991 100 none (00)272-(22)272 none (08)297-(23)297 (05)310-(00)311 1992 99 318-322 (12)342-(19)342 362 (11)343-(23)343 (13)357-(07)358 (15)359-(00)360 (16)361-(23)361 1993 77 183-191,243-314,346- none none 350,358-360 1994 98 52-54,131-134, none 205-209 144-146 1995 48 82-85,118-121, (10)346-(22)346 103-107,122-124,133- 181-365 (05)347-(22)347 137,152-155,162-165 1996 72 1-92,226-228,239- none 183,197-198,331-332 243,263-266 1997 60 18-21,153-155,212- none none