Johnston Island (USA Trust) Site History

History Summary

Station Johnston
Country USA Trust
Latitude 16° 44.3' N
Longitude 169° 31.8' W
GLOSS No 109
Time Reference GMT (hours 00-23)
Contributor National Ocean Service (NOS) National Ocean. and Atmos. Administration (NOAA)
Instrument Type Standard mechanical (1947-1974);
Analog-to-digital (ADR) recorder (1976-1990);
Aquatrak acoustic gauge, NOAA Next Generation Water Level Measuring System (NGWLMS) (1991-2000)
Site of Gauge  
Observational Periods 1947 - 2000

Please note that the position information has been altered in this document - see document 83916

Reference Level

All heights have been referred to the station tide staff zero which is linked to fixed benchmarks.

Tide Gauge Benchmark (TGBM) Description

Benchmark 13(1955) is the primary benchmark (PBM) stamped 'NO 13 1955' set in a concrete bulkhead cap at the inshore end of the small boat pier.

Auxiliary Benchmarks

9 additional benchmarks are levelled to the TGBM and the Tide Station on a yearly basis.

Benchmark Relationships

TGBM is 9.35ft above Tide Gauge Zero (Station Datum)

NOAA Chart Datum (MLLW) is 1.74ft above Station Datum

Mean Sea Level (1960-1978) is 2.81ft above Station Datum

Quality Assessment

Comments

The timing accuracy was typically no better than ±5 min prior to 1976. Large fluctuations during November - April for most years are associated with meteorological events.

A reference level correction of +15 cm was applied to the original data during 11Z 03 November - 01Z 27 November 1980. Otherwise, the daily and monthly means reveal no apparent reference level changes or trends.

The data for 1996-2000 were supplied with heights relative to MLLW. Consequently 530mm was added to refer the data to tide gauge zero.

The data for 1998-2000 were supplied in non-GMT format and had to be shifted into GMT.

Notable episodic events:

Gaps in the Data Record

The following gaps occur in the data set.

Year CI (%) Missing Data Replaced Gaps or Bad Data Questionable Fluctuations
    316,324-329,330-331    
1948 69 66-75,87-89,95-97,101-105,110-111,116-121,178-245,314-316,319-329,341-344,359-361,363-364,365-366 (11)346-(19)346(10)349-(18)349,(11)350-(19)350,(12)352-(19)352,(04)354-(18)354,(05)362-(17)362 None
1949 52 1-2,85-116,120-121,225-365 (11)033-(10)034,(06)075-(01)076,(10)080-(05)081,(14)081-(06)082,(06)117-(20)117,(06)118-(19)118 None
1950 91 1-32 None None
1951 100 None None None
1952 90 13-15,56-63,73-80,82-84,98-100,154-161,169-172,220-231 (02)016-(10)016,(15)016-(10)017,(15)025-(04)026,(01)089-(23)089,(03)090-(10)090,(03)091-(10)091,(19)094-(14)095,(21)096-(04)097,(21)097-(16)098,(11)100-(04)101,(13)218-(10)219,(16)238-(09)239,(16)239-(09)240,(16)240-(09)241,(17)243-(10)244 None
1953 75 56-148 None None
1954 98 327-335 None None
1955 100 None (10)165-(19)165 None
1956 100 None (17)025-(02)026 None
1957 100 None (14)017-(21)017,(15)154-(22)154,(17)172-(00)173,(22)354-(05)355 None
1958 98 51-58 (04)040-(11)040,(17)040-(12)041,(06)042-(14)042 13,167
1959 100 None None None
1960 100 None (17)240-(01)241,(03)241-(10)241 None
1961 100 None (00)018-(10)018,(08)359-(17)359 None
1962 97 71-83,285-365 (11)060-(20)060 62
1963 88 1-32,224-236 (19)213-(08)214,(11)245-(18)245 None
1964 100 None None None
1965 92 183-213 None None
1966 100 None (01)306-(08)306 None
1967 92 1-32 (17)072-(02)073,(10)085-(18)085,(21)274-(05)275,(06)325-(13)325 None
1968 100 None None None
1969 100 None (22)077-(15)078 None
1970 100 None None None
1971 99 343-346 (03)276-(13)276,(10)338-(18)338,(03)356-(21)356 None
1972 100 None None 233
1973 98 213-215,220-224,230-233 (03)128-(17)128,(03)217-(20)217,(13)218-(21)218,(02)226-(21)226,(22)227-(21)228,(11)330-(21)330 136-137
1974 100 None None None
1975 100 None None None
1976 100 None None None
1977 100 None None None
1978 100 None None None
1979 100 None None None
1980 100 None None None
1981 100 None None None
1982 100 None None None
1983 98 62-70 None None
1984 100 None None None
1985 100 None None None
1986 100 None None 258-269
1987 99 228-229 None None
1988 100 None None None
1989 100 None None None
1990 100 None None None
1991 95 291-303,345-351 None None
1992 100 None None None
1993 100 None None None
1994 100 None None 238
1995 100 None None None
1996 100 None None None
1997 100 None None None
1998 100 None None 58-64,67-68,73,78,90-102,107-115,127-139,144-150,157-162,219-226,232-267,291-298,302
1999 39 142-365 (11)085,(19)141 141-142
2000 42 1-213 None 214-223,227-248,255-262,267-271,282-295,298-305,318-325,333-343,347-352