QUALITY ASSESSMENT OF SEA LEVEL DATA by the UH SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER JOINT ARCHIVE FOR SEA LEVEL updated: Mar 17 2000 Station : Beihai Latitude: 21 29.0N Country : China Longitude: 109 05.0E JASL # : 636A Time Meridian: 120E (GMT + 8 hr) GLOSS # : none Originators-#: 45009 NODC #: 12101901 Contributor : PRC National Oceanographic Data Center 118, Qiwei Road, Hedong District Tianjin, China Originator : same Original Data: analog Instrmnt Type: unconfirmed (1975-84); HCJ-1 Float gauge (1985); SCA1-1 Float gauge (1986-1994); HCAI-1 float gauge (1995-) Digitzd Intvl: hourly Present Data : Hourly, daily, and monthly values obtained by: Hourly : digitized as hourly values 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 1975 - 31 Dec 1997 Gaps > 1 mon : none Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 Units : millimeters Missing Data Flag : 9999 Existing : Yes Operational : Yes Sat. Trans. : No Distribution : 1975-1997 Refernce Levl: The sea level heights are referred to the Tide Gauge Zero (TGZ) which is linked to fixed bench marks. Bench mark information is available upon request from the contributors. Comment : The residual series are very noisy which are probably due to shallow water tides that are not resolved by the harmonic analysis. Also the daily plot shows noise due to a great amount of energy with periods from 1 to 5 days. The mean level is steady. This data set is of good quality. CI MISSING REPLACED GAPS QUESTIONABLE YEAR (%) DATA OR BAD DATA FLUCTUATIONS ---- --- -------------------- --------------- -------------------- 1975 100 none (01)168-(23)168 see comment above (21)196-(04)197 (05)199-(23)199 (04)201-(23)201 (03)240-(23)240 (11)241-(23)241 (03)312-(23)312 (09)317-(00)318 (04)319-(00)320 1976 97 99-103,114-115, (12)097-(23)097 see comment above 214-219,289-293 (14)104-(02)105 (11)105-(00)106 (16)211-(23)211 (04)212-(23)212 (10)213-(23)213 1977 99 205-207 (16)107-(23)107 see comment above (16)203-(15)204 (01)205-(11)205 (14)207-(00)208 (11)223-(23)223 1978 100 none none see comment above 1979 100 none (16)090-(23)090 see comment above 1980 100 none (16)203-(23)203 see comment above 1981 100 none (14)298-(23)298 see comment above 1982 100 none none see comment above 1983 100 none (15)071-(23)071 see comment above 1984 100 none none see comment above 1985 100 none (13)289-(23)289 see comment above 1986 100 none none see comment above 1987 100 none none see comment above 1988 100 none none see comment above 1989 100 none (13)157-(23)157 see comment above 1990 100 none none see comment above 1991 100 none none see comment above 1992 100 none none see comment above 1993 100 none (13)006-(23)006 see comment above 1994 100 none none see comment above 1995 100 none none see comment above 1996 100 none none see comment above 1997 99 365 none see comment above