186SL0950172150501 552A 19890228 19931231 2002N 15550W 2 00000R 0000 MM 186SL0950272150501 Kawaihae USA National Ocean Service 186SL095030001 186SL095030002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL095030003 by the 186SL095030004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL095030005 JOINT ARCHIVE FOR SEA LEVEL 186SL095030006 186SL095030007Station : Kawaihae Latitude: 20 02.0N 186SL095030008Country : USA Longitude: 155 50.0W 186SL095030009JASL # : 552A Time Meridian: 150W (GMT - 10 hr) 186SL095030010GLOSS # : none TOGA #: none NODC #: 72150501 186SL095030011Contributor : National Ocean Service (NOS) 186SL095030012 National Ocean. and Atmos. Administration (NOAA) 186SL095030013 N/OES22 186SL095030014 SSMC4, STATION 7109 186SL095030015 1305 East West Highway 186SL095030016 Silver Spring, MD. 20910-3233 186SL095030017Originator : same 186SL095030018Original Data: digital 186SL095030019Instrmnt Type: Aquatrak acoustic gauge, NOAA Next Generation 186SL095030020 Water Level Measuring System (NGWLMS) 186SL095030021Digitzd Intvl: six-minute 186SL095030022Present Data : Hourly, daily, and monthly values obtained by: 186SL095030023 Hourly : The original digitizing interval was hourly 186SL095030024 (standard); spot sampling on the hour (adr/NGWLMS) 186SL095030025 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL095030026 centered on noon applied to the hourly data 186SL095030027 with respective periods of the 95, 50, and 5% 186SL095030028 amplitude points at 124.0, 60.2, and 40.2 hours 186SL095030029 Monthly: Simple average of all daily values; calculated if 186SL095030030 7 or fewer days are missing 186SL095030031Span of data : 28 Feb 1989 - 31 Dec 1993 186SL095030032Gaps > 1 mon : 23 Apr 1989 - 28 Aug 1989;30 Jan 1990 - 11 Apr 1990 186SL095030033 13 Oct 1992 - 25 Jan 1993 186SL095030034Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL095030035Units : millimeters Missing Data Flag :99999 186SL095030036Refernce Levl: All heights have been referred to the station tide 186SL095030037 staff zero which is linked to fixed bench marks 186SL095030038Comment : The daily and monthly means reveal no apparent 186SL095030039 reference level changes or trends and agree with 186SL095030040 the nearest stations. 186SL095030041 186SL095030042 CI MISSING REPLACED GAPS QUESTIONABLE 186SL095030043YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL095030044---- --- -------------------- --------------- -------------------- 186SL0950300451989 49 113-240 none none 186SL0950300461990 81 30-101 none none 186SL0950300471991 98 52-59 none none 186SL0950300481992 78 287-366 none none 186SL0950300491993 93 1-28 none none 186SL095030050 186SL095030051 QUALITY ASSESSMENT POLICY 186SL095030052 186SL095030053 The quality assessment is mostly based on the residuals 186SL095030054 (observed data minus predicted tides) of the hourly data. This 186SL095030055 assessment also applies to the daily and monthly data since 186SL095030056 they were derived from the quality-controlled hourly data. 186SL095030057 186SL095030058 The following abbreviations are used in the assessment: 186SL095030059 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL095030060 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL095030061 research program; NODC - National Oceanographic Data Center; 186SL095030062 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL095030063 Gaps > 1 mon - missing data in a span greater than one month; 186SL095030064 Refernce - reference. 186SL095030065 186SL095030066 The following corrections are made to the hourly data 186SL095030067 prior to this assessment: 186SL095030068 1) Gaps or obviously wrong data points in a span less than 186SL095030069 25 hours are filled by the predicted tide method*. 186SL095030070 2) Timing errors of exact increments of an hour are corrected 186SL095030071 by shifting the data. 186SL095030072 3) Reference level shifts are only corrected after information 186SL095030073 from tide staff readings or comparative readings with a fixed 186SL095030074 bench mark are checked to verify that the shift was not a 186SL095030075 natural event. If comparative readings are missing or 186SL095030076 incomplete, comparisons of the data with nearby stations 186SL095030077 may warrant the adjustment of some obvious shifts. 186SL095030078 4) Data with unresolved datum shifts are not disseminated. 186SL095030079 However, if sufficient time spans of data are available before 186SL095030080 or after the year(s) with the unresolved shift(s), a subset of 186SL095030081 quality assured data is made available. Thus, the Span field 186SL095030082 in the Quality Assessment may not match the span of the 186SL095030083 distribution data set. As the questionable datum shifts are 186SL095030084 resolved, the data set will be updated. Although this policy 186SL095030085 adds some complexity, it allows more rapid dissemination of 186SL095030086 at least the quality assured years. 186SL095030087 186SL095030088 For each year, the following information is documented from 186SL095030089 the quality-controlled hourly data with dates given as the nth 186SL095030090 day of the year starting from 1 January: 186SL095030091 1) a Completeness Index (CI) based on the percentage of hours 186SL095030092 with available data, 186SL095030093 2) a list of gaps longer than a day, 186SL095030094 3) a summary of days with consecutive missing or obviously 186SL095030095 wrong data in a time span longer than 6 but less than 25 186SL095030096 hours that have been replaced, with hours in parentheses, and 186SL095030097 4) a summary of days with questionable fluctuations in the 186SL095030098 residual series. Fluctuations within the residuals are 186SL095030099 considered significant and are noted if they are greater than 186SL095030100 25 cm. This policy has changed slightly as of October 1992: 186SL095030101 only suspicious fluctuations due to obvious instrumentation 186SL095030102 problems are noted. Minor timing drifts are no longer 186SL095030103 included in the list of questionable days. 186SL095030104 186SL095030105 Note : If the predicted tides poorly model the observed heights 186SL095030106 due to the inability of the tidal analysis to completely resolv 186SL095030107 the non-linear shallow water effects, the residuals are not 186SL095030108 suitable for assessing the data quality. Instead, a subjective 186SL095030109 comment on the quality of the data is provided. 186SL095030110 186SL095030111 *The predicted tides are obtained with the use of a harmonic 186SL095030112 analysis program (Foreman, 1977) which is executed on a year 186SL095030113 of apparently good data for a given station. The Predicted 186SL095030114 Tide Method for filling gaps consists of statistically 186SL095030115 comparing the predicted tides to the observed data and 186SL095030116 shifting the predicted tides in time to correct for timing 186SL095030117 differences. Then the linear interpolation between hourly 186SL095030118 values at the end points of the gap in the residual series is 186SL095030119 added to the corresponding corrected predicted tide data to 186SL095030120 obtain interpolated values over the span of the gap. 186SL095030121 186SL095030122 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL095030123 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL095030124 186SL095030125 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL095030126 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL095030127 Victoria B.C. Pacific Marine Science Report 77-10. 186SL095030128 186SL09506 19891 9999999999999999 1085000999999999999999999999999 186SL09506 19892 9999999999999999 1119000 1113000 1116000 1020000 186SL09506 19901 1053020999999999999999999999999 936000 973000 186SL09506 19902 984000 1021000 1062000 1081000 995000 1038000 186SL09506 19911 104100099999999 954000 938000 985000 973000 186SL09506 19912 1018000 1083000 969000 1020000 1106000 1080000 186SL09506 19921 1089000 1066000 1079000 1056000 1055000 1079000 186SL09506 19922 1074000 1037000 1081000999999999999999999999999 186SL09506 19931 99999999 1029000 1065000 1125000 1081000 1101000 186SL09506 19932 1129000 1068000 1129000 1097000 1021000 1050000