QUALITY ASSESSMENT OF SEA LEVEL DATA by the UH SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER JOINT ARCHIVE FOR SEA LEVEL Station : Rabaul Latitude: 04 12.0S Country : Papua New Guinea Longitude: 152 10.5E JASL # : 010A Time Meridian: 150E (GMT + 10 hr) GLOSS # : 065 TOGA #: P035 NODC #: 30154201 Contributor : University of Hawaii Sea Level Center 1000 Pope Rd. MSB 317 Honolulu, Hawaii 96822 and for 1966 - 1971 data: Flinders University of South Australia GPO Box 2100 Adelaide, 5001, South Australia AUSTRALIA Originator : Dept. of Oceanography University of Hawaii 1000 Pope Rd. MSB 317 Honolulu, Hawaii 96822 => and for 1966 - 1971 data Papua New Guinea Department of Mineral Resources Geological Survey Volcano Observatory P.O. Box 386 Rabaul, Papua New Guinea Original Data: digital; analog (ANA) Instrmnt Type: 1. (1974-present) Leupold and Stevens Analog-to-Digital Recorder (ADR); 2. (10/1984-present) Handar Encoder (ENC) 3. Volcano Observatory operates a Stevens A71 (ANA) analog gauge next to the UH punch tape instrument. It was first set up in 1966, with the initial weight-driven and timed instrument being replaced by a new, battery operated and quartz timed model in Jan 1997. The data are not normally digitized but have been used to fill gaps in the UH sensors and was the primary gauge for all of 1997. Primary gauge: ADR:1974-90, ENC: 1991-1996, ANA: 1997 Digitzd Intvl: 15 (ADR), 3 or 4 (ENC) minutes;(66-71 unconfirmed) Present Data : Hourly, daily, and monthly values obtained by: Hourly : 1966-71 spot hourly; for 1974 onwards as follows, (pre-1987) Nine-point triangular filter centered on the hour with respective periods of the 95, 50, and 5% amplitude point of the filter response at 623.6, 177.0, and 103.7 minutes;(1987+) three-point Hanning filter centered on the hour 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 : 06 Apr 1966 - 31 Dec 1997 Gaps > 1 mon : 15 Feb - 02 Jun 1970; 15 Jul - 16 Oct 1970 14 Apr 1971 - 11 Dec 1974 Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 Units : millimeters Missing Data Flag : 9999 Existing : Yes Operational : Yes Sat. Trans. : Yes Distribution : 1966-1997 Refernce Levl: Heights are referred to the station tide staff zero, which is linked to land-based benchmarks. This reference zero is unique to this station and is not an official datum (chart, national, etc.) and is not relative to local tidal parameters, such as mean lower low water. See the Originators for benchmark descriptions, maps, and the geodetic levelling history. Comment : The daily and monthly means reveal no apparent changes in the reference level and agree with Kapingamarangi. A volcanic eruption on 30 Sep, 1994 resulted in heavy subsidence until Oct 1. Based on geodetic leveling information provided by local authorities, -13 cm were added to the Oct 1994 data and -14 cm were added to Nov 1994 through 31 Dec 1997. A spike on 17 Feb 1996 is associated with a tsunami. In 1995, Rabaul Volcaological Observatory reported a subsidence of -21 cm, then a rise of 4 cm. However, dates of these events have not been specified and the geodetic survey data are not available. Thus there is uncertainty to the mean level for 1995- 1997. CI MISSING REPLACED GAPS QUESTIONABLE YEAR (%) DATA OR BAD DATA FLUCTUATIONS ---- --- -------------------- --------------- -------------------- 1966 74 none none 357-359 1967 100 none (02)326-(10)326 50-53,213-217 (02)327-(09)327 (01)329-(12)329 (02)332-(12)332 (19)333-(08)334 (01)335-(08)335 (22)335-(09)336 (23)336-(09)337 1968 85 89-145 none none 1969 73 23-28,71-77,102-121, (18)310-(05)311 none 167-178,194-212,278- 306,350-364 1970 40 12-18,46-153,196-289 none none 320-331,359-364 1971 28 104-365 none none 1972 0 1-366 none none 1973 0 1-365 none none 1974 6 none none none 1975 100 none none none 1976 100 none none none 1977 97 61-63,199-206 (11)059-(05)060 none 1978 97 21-23,99-108 (14)365-(23)365 none 1979 100 none none none 1980 100 none none none 1981 95 178-180,204-208, none none 211-218,334-335 1982 98 29-34,37-39 none none 1983 100 none none none 1984 100 none none none 1985 100 none none none 1986 100 none none none 1987 100 none none none 1988 100 none none none 1989 100 none none none 1990 100 none none none 1991 100 none none none 1992 100 none none none 1993 100 none none none 1994 97 262-275 none none 1995 100 none none none 1996 100 none (10)363-(02)364 none (10)364-(03)365 1997 99 11-14 (06)005-(19)005 none