Chichijima (Japan) Site History

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