Chichijima (Japan) Site History

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History Summmary

Station	Chichijima
Country	Japan
Latitude	27° 05.0' N
Longitude	142° 11.0' E
GLOSS No	103
Contributor	TOGA Sea Level Center (1975-1986) Japan Meteorological Agency (1987-2009)
Instrument Type	Float and stilling well gauge, LFT-4 gauge Fuess float operated gauge (2001-2005) Acoustic gauge (2006-2009)
Site of Gauge
Observational periods	1975 - present

Benchmarks

Reference Level

All heights have been referred to the station Tide Gauge Zero which is linked to fixed bench marks.

Tide Gauge Benchmark (TGBM) Description

Japan Meteorlogical Agency Benchmark bolt is inside the tide gauge hut, adjacent to the stilling well.

Benchmark Relationships

Year	Standard Mark (TGBM) above Datum Line (TGZ)	Standard Mark (TGBM) above MSL of station	TGZ below MSL
1975-2002	4.146	n/a	n/a
2003-2005	4.146	2.234	-1.912
2006	4.146	2.235	-1.911
2007	4.146	2.244	-1.902
2008	4.146	2.245	-1.901
2009	4.146	2.278	-1.868

Parameter Code

ASLVZZ01 - The elevation of the sea surface to a known datum, measured in metres.

Quality Assessment

The daily or monthly means do not reveal any obvious reference level shifts. Prior to 2001 most questionable fluctuations are related to timing problems with the gauge. Data spikes of about 10cm or less have not been corrected.

Completeness index (CI)

Sea level data from Japan is processed for each year. Occasionally data is missing from the data sets, either because the data set does not cover the whole year or because data has been flagged null. The number of cycles in a year with no missing data is calculated (based on the sample interval and whether a leap year). The completeness index calculates what proportion of the data expected in a year is present and not flagged null.

Quality index (QI)

During processing cycles considered suspect within a series are flagged M. The quality index calculates what proportion of the data available is not considered suspect.

Yearly overview of data

Year	CI (%)	QI (%)	Start and end date (UTC)	Sampling interval (minutes)	Missing Data (cycle no.)	Suspect Data (cycle no.)	Parameter Code
1975	75.6	100.0	1975-03-31 01:00 to 1975-12-31 23:00	60	None	None	ASLVZZ01
1976	99.6	98.0	1976-01-01 00:00 to 1976-12-31 23:00	60	4312-4343	6959-7137	ASLVZZ01
1977	99.7	100.0	1977-01-01 00:00 to 1977-12-31 23:00	60	6368-6393	None	ASLVZZ01
1978	100.0	100.0	1978-01-01 00:00 to 1978-12-31 23:00	60	None	None	ASLVZZ01
1979	93.9	100.0	1979-01-01 00:00 to 1979-12-31 23:00	60	1109-1640	None	ASLVZZ01
1980	100.0	100.0	1980-01-01 00:00 to 1980-12-31 23:00	60	None	None	ASLVZZ01
1981	100.0	100.0	1981-01-01 00:00 to 1981-12-31 23:00	60	None	None	ASLVZZ01
1982	100.0	100.0	1982-01-01 00:00 to 1982-12-31 23:00	60	None	None	ASLVZZ01
1983	100.0	100.0	1983-01-01 00:00 to 1983-12-31 23:00	60	None	None	ASLVZZ01
1984	100.0	100.0	1984-01-01 00:00 to 1984-12-31 23:00	60	None	None	ASLVZZ01
1985	100.0	100.0	1985-01-01 00:00 to 1985-12-31 23:00	60	None	None	ASLVZZ01
1986	99.9	100.0	1986-01-01 00:00 to 1986-12-31 14:00	60	None	None	ASLVZZ01
1987	99.4	100.0	1986-12-31 15:00 to 1987-12-31 14:00	60	10-29, 390-393, 6177-6201	None	ASLVZZ01
1988	99.6	100.0	1987-12-31 15:00 to 1988-12-31 14:00	60	754-777, 4602-4604, 4625-4628, 4641-4643	None	ASLVZZ01
1989	99.3	100.0	1988-12-31 15:00 to 1989-12-31 14:00	60	1053-1064, 1226-1232, 2410-2411, 3141-3153, 3992-3997, 5142-5145, 6412-6417, 7942-7953	None	ASLVZZ01
1990	99.5	100.0	1989-12-31 15:00 to 1990-12-31 14:00	60	1379-1425	None	ASLVZZ01
1991	99.5	100.0	1990-12-31 15:00 to 1991-12-31 14:00	60	None	None	ASLVZZ01
1992	100.0	100.0	1991-12-31 15:00 to 1992-12-31 14:00	60	None	None	ASLVZZ01
1993	100.0	100.0	1992-12-31 15:00 to 1993-12-31 14:00	60	None	None	ASLVZZ01
1994	100.0	100.0	1993-12-31 15:00 to 1994-12-31 14:00	60	None	None	ASLVZZ01
1995	100.0	100.0	1994-12-31 15:00 to 1995-12-31 14:00	60	None	None	ASLVZZ01
1996	100.0	100.0	1995-12-31 15:00 to 1996-12-31 14:00	60	None	None	ASLVZZ01
1997	100.0	99.5	1996-12-31 15:00 to 1997-12-31 14:00	60	None	6239-6256, 7062-7077, 7454-7465	ASLVZZ01
1998	100.0	100.0	1998-01-01 00:00 to 1998-12-31 23:00	60	None	None	ASLVZZ01
1999	100.0	100.0	1999-01-01 00:00 to 1999-12-31 23:00	60	None	None	ASLVZZ01
2001	100.0	100.0	2000-12-31 15:00 to 2001-12-31 14:00	60	None	None	ASLVZZ01
2002	100.0	100.0	2001-12-31 15:00 to 2002-12-31 14:00	60	None	None	ASLVZZ01
2003	100.0	100.0	2002-12-31 15:00 to 2003-12-31 14:00	60	None	None	ASLVZZ01
2004	100.0	100.0	2003-12-31 15:00 to 2004-12-31 14:00	60	None	None	ASLVZZ01
2005	100.0	100.0	2004-12-31 15:00 to 2005-12-31 14:00	60	None	None	ASLVZZ01
2006	99.9	100.0	2005-12-31 15:00 to 2006-12-31 14:00	60	8269-8271, 8290-8291	None	ASLVZZ01
2007	100.0	100.0	2006-12-31 15:00 to 2007-12-31 14:00	60	None	None	ASLVZZ01
2008	99.9	100.0	2007-12-31 15:00 to 2008-12-31 14:00	60	8052-8055	None	ASLVZZ01
2009	99.9	100.0	2008-12-31 15:00 to 2009-12-31 14:00	60	None	None	ASLVZZ01

Replaced gaps

Year	Replaced Gaps (UTC)
1975	1975-07-17 14:00 to 1975-07-17 22:00
1977	1977-04-06 20:00 to 1977-04-07 06:00 1977-06-01 13:00 to 1977-06-01 23:00 and 1977-06-03 07:00 to 1977-06-05 14:00.
1978	1978-11-18 06:00 to 1978-11-18 12:00
1981	1981-07-17 12:00 to 1981-07-18 03:00 1981-08-18 11:00 to 1981-08-18 22:00 and 1981-11-08 14:00 to 1981-11-08 21:00.
1982	1982-05-10 17:00 to 1982-05-11 14:00 and 1982-07-23 19:00 to 1982-07-24 13:00
1983	1983-01-27 14:00 to 1983-01-27 22:00 1983-01-28 03:00 to 1983-01-28 10:00 1983-02-26 12:00 to 1983-02-26 22:00 and 1983-02-27 03:00 to 1983-02-27 10:00
1984	1984-07-30 12:00 to 1984-07-30 18:00 1984-08-24 11:00 to 1984-08-24 18:00 and 1984-10-10 17:00 to 1984-10-10 23:00
1985	1985-12-20 03:00 to 1985-12-20 15:00
1986	1986-09-24 09:00 to 1986-09-25 02:00