186SL0674111161201 006A 19540101 19701231 1126N 16223E 2 00000R 0000 MM 186SL0674211161201 Enewetok-A Rep. Marshall I. Scripps Inst. Ocean. 186SL067430001 186SL067430002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL067430003 by the 186SL067430004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL067430005 JOINT ARCHIVE FOR SEA LEVEL 186SL067430006 186SL067430007Station : Enewetok-A Latitude: 11 25.8N 186SL067430008Country : Republic of Marshall Is. Longitude: 162 23.2E 186SL067430009JASL # : 006A Time Meridian: 165E (GMT + 11 hr) 186SL067430010GLOSS # : 110 TOGA #: none NODC #: 11161201 186SL067430011Contributor : Scripps Institute of Oceanography 186SL067430012 University of California at San Diego 186SL067430013 La Jolla, California 186SL067430014Originator : unconfirmed 186SL067430015Original Data: unconfirmed 186SL067430016Instrmnt Type: unconfirmed 186SL067430017Digitzd Intvl: unconfirmed 186SL067430018Present Data : Hourly, daily, and monthly values obtained by: 186SL067430019 Hourly : unconfirmed 186SL067430020 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL067430021 centered on noon applied to the hourly data 186SL067430022 with respective periods of the 95, 50, and 5% 186SL067430023 amplitude points at 124.0, 60.2, and 40.2 hours 186SL067430024 Monthly: Simple average of all daily values; calculated if 186SL067430025 7 or fewer days are missing 186SL067430026Span of data : 01 Jan 1954 - 31 Dec 1970 186SL067430027Gaps > 1 mon : 31 Dec 1955 - 02 Feb 1958;30 Dec 1962 - 31 Oct 1968 186SL067430028Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL067430029Units : millimeters Missing Data Flag :99999 186SL067430030Refernce Levl: All heights have been referred to the station tide 186SL067430031 staff zero which is linked to fixed bench marks 186SL067430032Comment : The daily and monthly means reveal no apparent 186SL067430033 changes in the reference level. Timing accuracy 186SL067430034 was no better than +/- 15 minutes. This series 186SL067430035 is distinguished from Enewetok-B because the data 186SL067430036 have not been linked to a common datum. 186SL067430037 186SL067430038 CI MISSING REPLACED GAPS QUESTIONABLE 186SL067430039YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL067430040---- --- -------------------- --------------- -------------------- 186SL0674300411954 100 none none none 186SL0674300421955 99 365 none none 186SL0674300431956 0 1-366 none none 186SL0674300441957 0 1-365 none none 186SL0674300451958 91 1-33 none 283-284,299 186SL0674300461959 100 none none none 186SL0674300471960 100 none none none 186SL0674300481961 100 none none none 186SL0674300491962 99 364-365 none none 186SL0674300501963 0 1-365 none none 186SL0674300511964 0 1-366 none none 186SL0674300521965 0 1-365 none none 186SL0674300531966 0 1-365 none none 186SL0674300541967 0 1-365 none none 186SL0674300551968 17 1-305 none none 186SL0674300561969 96 243-245,256-260, none none 186SL067430057 266-274 186SL0674300581970 99 365 none none 186SL067430059 186SL067430060 QUALITY ASSESSMENT POLICY 186SL067430061 186SL067430062 The quality assessment is mostly based on the residuals 186SL067430063 (observed data minus predicted tides) of the hourly data. This 186SL067430064 assessment also applies to the daily and monthly data since 186SL067430065 they were derived from the quality-controlled hourly data. 186SL067430066 186SL067430067 The following abbreviations are used in the assessment: 186SL067430068 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL067430069 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL067430070 research program; NODC - National Oceanographic Data Center; 186SL067430071 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL067430072 Gaps > 1 mon - missing data in a span greater than one month; 186SL067430073 Refernce - reference. 186SL067430074 186SL067430075 The following corrections are made to the hourly data 186SL067430076 prior to this assessment: 186SL067430077 1) Gaps or obviously wrong data points in a span less than 186SL067430078 25 hours are filled by the predicted tide method*. 186SL067430079 2) Timing errors of exact increments of an hour are corrected 186SL067430080 by shifting the data. 186SL067430081 3) Reference level shifts are only corrected after information 186SL067430082 from tide staff readings or comparative readings with a fixed 186SL067430083 bench mark are checked to verify that the shift was not a 186SL067430084 natural event. If comparative readings are missing or 186SL067430085 incomplete, comparisons of the data with nearby stations 186SL067430086 may warrant the adjustment of some obvious shifts. 186SL067430087 4) Data with unresolved datum shifts are not disseminated. 186SL067430088 However, if sufficient time spans of data are available before 186SL067430089 or after the year(s) with the unresolved shift(s), a subset of 186SL067430090 quality assured data is made available. Thus, the Span field 186SL067430091 in the Quality Assessment may not match the span of the 186SL067430092 distribution data set. As the questionable datum shifts are 186SL067430093 resolved, the data set will be updated. Although this policy 186SL067430094 adds some complexity, it allows more rapid dissemination of 186SL067430095 at least the quality assured years. 186SL067430096 186SL067430097 For each year, the following information is documented from 186SL067430098 the quality-controlled hourly data with dates given as the nth 186SL067430099 day of the year starting from 1 January: 186SL067430100 1) a Completeness Index (CI) based on the percentage of hours 186SL067430101 with available data, 186SL067430102 2) a list of gaps longer than a day, 186SL067430103 3) a summary of days with consecutive missing or obviously 186SL067430104 wrong data in a time span longer than 6 but less than 25 186SL067430105 hours that have been replaced, with hours in parentheses, and 186SL067430106 4) a summary of days with questionable fluctuations in the 186SL067430107 residual series. Fluctuations within the residuals are 186SL067430108 considered significant and are noted if they are greater than 186SL067430109 25 cm. This policy has changed slightly as of October 1992: 186SL067430110 only suspicious fluctuations due to obvious instrumentation 186SL067430111 problems are noted. Minor timing drifts are no longer 186SL067430112 included in the list of questionable days. 186SL067430113 186SL067430114 Note : If the predicted tides poorly model the observed heights 186SL067430115 due to the inability of the tidal analysis to completely resolv 186SL067430116 the non-linear shallow water effects, the residuals are not 186SL067430117 suitable for assessing the data quality. Instead, a subjective 186SL067430118 comment on the quality of the data is provided. 186SL067430119 186SL067430120 *The predicted tides are obtained with the use of a harmonic 186SL067430121 analysis program (Foreman, 1977) which is executed on a year 186SL067430122 of apparently good data for a given station. The Predicted 186SL067430123 Tide Method for filling gaps consists of statistically 186SL067430124 comparing the predicted tides to the observed data and 186SL067430125 shifting the predicted tides in time to correct for timing 186SL067430126 differences. Then the linear interpolation between hourly 186SL067430127 values at the end points of the gap in the residual series is 186SL067430128 added to the corresponding corrected predicted tide data to 186SL067430129 obtain interpolated values over the span of the gap. 186SL067430130 186SL067430131 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL067430132 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL067430133 186SL067430134 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL067430135 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL067430136 Victoria B.C. Pacific Marine Science Report 77-10. 186SL067430137 186SL06746 19541 1389000 1367000 1315000 1345000 1390000 1355000 186SL06746 19542 1295000 1326000 1308000 1255000 1279000 1304000 186SL06746 19551 1314000 1364000 1357000 1375000 1340000 1338000 186SL06746 19552 1352000 1368000 1369000 1388000 1382000 1362010 186SL06746 19561 999999999999999999999999999999999999999999999999 186SL06746 19562 999999999999999999999999999999999999999999999999 186SL06746 19571 999999999999999999999999999999999999999999999999 186SL06746 19572 999999999999999999999999999999999999999999999999 186SL06746 19581 99999999 1241020 1254000 1259000 1351000 1355000 186SL06746 19582 1333000 1337000 1349000 1313000 1313000 1297000 186SL06746 19591 1243000 1239000 1275000 1337000 1361000 1332000 186SL06746 19592 1329000 1360000 1340000 1247000 1282000 1260000 186SL06746 19601 1235000 1271000 1283000 1334000 1344000 1411000 186SL06746 19602 1434000 1393000 1375000 1368000 1313000 1279000 186SL06746 19611 1338000 1356000 1382000 1407000 1385000 1385000 186SL06746 19612 1400000 1445000 1427000 1390000 1340000 1309000 186SL06746 19621 1341000 1366000 1376000 1401000 1464000 1425000 186SL06746 19622 1482000 1454000 1425000 1415000 1384000 1360020 186SL06746 19631 999999999999999999999999999999999999999999999999 186SL06746 19632 999999999999999999999999999999999999999999999999 186SL06746 19641 999999999999999999999999999999999999999999999999 186SL06746 19642 999999999999999999999999999999999999999999999999 186SL06746 19651 999999999999999999999999999999999999999999999999 186SL06746 19652 999999999999999999999999999999999999999999999999 186SL06746 19661 999999999999999999999999999999999999999999999999 186SL06746 19662 999999999999999999999999999999999999999999999999 186SL06746 19671 999999999999999999999999999999999999999999999999 186SL06746 19672 999999999999999999999999999999999999999999999999 186SL06746 19681 999999999999999999999999999999999999999999999999 186SL06746 19682 99999999999999999999999999999999 1218000 1208000 186SL06746 19691 1154000 1187000 1207000 1308000 1281000 1318000 186SL06746 19692 1343000 134901099999999 1310000 1256000 1240000 186SL06746 19701 1289000 1351000 1408000 1413000 1419000 1473000 186SL06746 19702 1485000 1451000 1444000 1449000 1443000 1409010