QUALITY ASSESSMENT OF SEA LEVEL DATA by the UH SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER JOINT ARCHIVE FOR SEA LEVEL updated: 15 Sep 2020 Station : Sand Point,Popof Is.,AK Latitude: 55 20.2N Country : USA Longitude: 160 30.1W JASL # : 574A Time Meridian: 150W (GMT - 10 hr) GLOSS # : 100 Originator #:9459450 NODC #: 75165001 Contributor : National Ocean Service (NOS) National Ocean. and Atmos. Administration (NOAA) N/OES22 SSMC4, STATION 7109 1305 East West Highway Silver Spring, MD. 20910-3233 *1973-1995 were processed and provided by Dr. David Jay of Portland State University Originator : US Coastal Geodetic Survey (1901-1972);NOS (1973+) Original Data: digital (ADR and NGWLMS) Instrmnt Type: analog-to-digital (ADR) recorder, float/wire (1973-1991); Aquatrak acoustic sensor/protective well, NOAA Next Generation Water Level Measuring System (NGWLMS) (1991-) Digitzd Intvl: six-minute; NGWLMS sampling is three-minute average Present Data : Hourly, daily, and monthly values obtained by: Hourly : spot sampling on the hour 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 1973 - 31 Dec 2019 Gaps > 1 mon : 01 May 1973 - 09 Jun 1973;23 Sep 1977 - 13 Mar 1978 23 Sep 2005 - 28 Dec 2005 Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 Units : millimeters Missing Data Flag : 9999 Existing : Yes Operational : Yes Sat. Trans. : Yes Distribution : 1973-2019 Refernce Levl: All heights have been referred to the station tide staff zero which is linked to fixed bench marks. A constant offset of -9144 mm (-30') was added to the original data to fit the JASL format. Comment : The daily and monthly means reveal no apparent reference level changes or trends. Tsunamis are evident in the record on 28 Feb 2010 (Chile) and 11 Mar 2011 (Japan). CI MISSING REPLACED GAPS QUESTIONABLE YEAR (%) DATA OR BAD DATA FLUCTUATIONS ---- --- -------------------- --------------- -------------------- 1973 84 15-36,121-160 none none 1974 100 none none 19-21 1975 90 283-304,309-323 none none 1976 93 92-116 none none 1977 71 75-81,125-126,266- (18)176-(16)177 none 365 1978 79 1-72,196-198,240-243 none none 1979 91 306-318,323-343 none 114-121,318-323 1980 89 92-117,180-197 none 153-157,347-350 1981 100 none none none 1982 100 none none none 1983 100 none none none 1984 100 none none none 1985 100 none none 180-182 1986 100 none none none 1987 100 none none 200 1988 100 none none none 1989 100 none none none 1990 100 none none none 1991 100 none none none 1992 100 none none none 1993 100 none none none 1994 100 none none none 1995 100 none none none 1996 100 none none none 1997 100 none none none 1998 100 none none none 1999 100 none none none 2000 100 none none 33 2001 100 none none none 2002 100 none none none 2003 100 none none none 2004 100 none none none 2005 74 266-362 none 199-191 2006 100 none none none 2007 100 none none none 2008 100 none none none 2009 100 none none none 2010 100 none none none 2011 100 none none none 2012 100 none none none 2013 100 none none none 2014 100 none none none 2015 100 none none none 2016 100 none none none 2017 100 none none none 2018 100 none none none 2019 100 none none none