Truk Atoll (Carolines, Micronesia) Site History

History Summary

Station Truk
Country Fed. States Micronesia
Latitude 07° 27.0' N
Longitude 151° 51.0' E
GLOSS No 116
Time Reference GMT (hours 00-23)
Contributors National Ocean Service (NOS)
National Ocean. and Atmos. Administration (NOAA)
Instrument Type Standard mechanical (1947-1974)
Analog-to-digital (ADR) recorder (1975-1990)
Aquatrak acoustic gauge,
NOAA Next Generation Water Level Measuring System (NGWLMS) (1991-)
Site of Gauge The gauge is situated outside the public works, directly opposite Gout Pier.
Observational periods 1947 - 1991

Reference Level

All heights have been referred to the station tide staff zero which is linked to fixed benchmarks. Differences with PSMSL data suggest level uncertainty prior to 1963.

Tide Gauge Benchmark (TGBM) Description

Benchmark B (1948) is the primary benchmark and is stamped 'B 1948'. It is set into the concrete pavement along the north side of a row of 6 Quonset warehouses, east of the government pier.

Five additional benchmarks are levelled to the TGBM and tide station on a yearly basis.

Datum Levels

The Tide Gauge Benchmark is 8.05 feet above the Tide Gauge Zero (Station Datum). NOAA Chart Datum is 2.73 feet above Station Datum and the mean sea level (1960-1978) is 3.58 feet above Station Datum.

Quality Assessment

Comments

The daily and monthly means reveal no apparent reference level changes or trends.

The timing appears to be off by roughly 6 minutes from September - January 1992.

A datum shift of -0.65m has been corrected during the period 31/05/94(1700)-31/05/94(2300).

Notable episodic events:

Year CI(%) Missing Data Replaced Gaps or bad Data Questionable Fluctuations
1948 50 1-9,116-277,289-293,295-299,361-366 (09)282-(23)282 (11)080-(23)080 336,353-356
1949 34 1-83,121-273,337-340,357-360,363-365 (01)336-(00)337 (13)341-(21)341 (11)360-(02)361 (11)361-(02)362 (07)362-(02)363 none
1950 92 1-7,16-17,181-184,200-202,207-212,220-222,225-229,236-238,242-243,266-267,285-289 (16)025-(05)026 (19)124-(02)125 (15)184-(08)185 (15)187-(07)188 (17)188-(01)189 (23)192-(08)193 (01)198-(08)198 (10)198-(03)199 (15)204-(03)205 (15)212-(23)212 (14)224-(21)224 (23)268-(07)269 (22)270-(08)271 (23)273-(23)273 (17)281-(13)282 (13)284-(07)285 146-148
1951 60 155-303 (23)051-(06)052 (14)084-(13)085 (21)119-(06)120 (21)120-(23)120 (22)121-(05)122 none
1952 35 9-243,259-261,266-268 (17)335-(23)335 none
1953 100 none (14)089-(13)090 (14)134-(13)135 (14)223-(13)224 (04)313-(20)313 none
1954 100 none (08)167-(01)168 none
1955 34 126-365 none none
1956 91 1-36 none none
1957 100 none none none
1958 92 336-365 none none
1959 100 none none none
1960 88 20-65 none none
1961 100 none none none
1962 100 none (00)330-(18)330 none
1963 100 none none none
1964 100 none none none
1965 100 none none none
1966 100 none none none
1967 92 181-212 none none
1968 100 none none none
1969 100 none none none
1970 100 none none none
1971 100 none (15)274-(23)274 (18)349-(10)350 none
1972 99 161-163 (00)174-(22)174 none
1973 100 none (02)226-(17)226 (23)227-(09)228 (12)231-(20)231 (07)309-(21)309 (15)326-(22)326 none
1974 100 none (22)347-(09)348 (22)348-(12)349 (14)365-(23)365 none
1975 83 304-365 none 59-60
1976 75 25-48,63-69,72-83,121-122,251-297,360-362 (05)251-(13)251 none
1977 91 8-9,11-30,49-52,82-92 none none
1978 94 10-12,66-69,92-93,274-287,348-349 (06)046-(05)047 (01)100-(23)100 (10)106-(21)106 none
1979 99 37-39,102-105,119-121 none 146
1980 100 none none none
1981 94 222-243 none none
1982 100 none none none
1983 100 none none none
1984 100 335-336 none none
1985 100 none none none
1986 100 212 none 60-63
1987 78 259-266,276-278 none 272,274-275
1988 86 none none none
1989 100 none none none
1990 90 none none none
1991 91 107-127,199-222,245-246 none See comment above
1992 7 27-366 none See comment above
1993 9 1-333 none none
1994 100 none none none
1995 56 205-365 none none