186SL0685131178801 018A 19751029 19911231 1808S 17826E 2 00000R 0000 MM 186SL0685231178801 Suva Fiji TOGA Sea Level Center 186SL068530001 186SL068530002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL068530003 by the 186SL068530004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL068530005 JOINT ARCHIVE FOR SEA LEVEL 186SL068530006 186SL068530007Station : Suva-A Latitude: 18 07.9S 186SL068530008Country : Fiji Longitude: 178 25.6E 186SL068530009JASL # : 018A Time Meridian: 180E (GMT + 12 hr) 186SL068530010GLOSS # : 122 TOGA #: P047 NODC #: 31178801 186SL068530011Contributor : TOGA Sea Level Center (1975-5/1989) 186SL068530012 1000 Pope Rd. MSB 317 186SL068530013 Honolulu, Hawaii 96822 186SL068530014 and National Ocean Service (NOS) (6/1989-1991) 186SL068530015 National Ocean. and Atmos. Administration (NOAA) 186SL068530016 Rockville, Maryland 20852 186SL068530017Originator : same as above for both time periods 186SL068530018Original Data: digital 186SL068530019Instrmnt Type: Float and well gauges: 1) 1975-5/1989:Fischer and 186SL068530020 Porter Analog-to-Digital Recorder 2) 6/1989-1990: 186SL068530021 Leupold and Stevens ADR gauge 3) Aquatrak acoustic 186SL068530022 gauge, NOAA Next Generation Water Level Measuring 186SL068530023 System (NGWLMS) (1991-) 186SL068530024Digitzd Intvl: 15 minutes (F&P), 6 minutes (L&S,NGWLMS) 186SL068530025Present Data : Hourly, daily, and monthly values obtained by: 186SL068530026 Hourly : (pre-1987) Nine-point triangular filter centered 186SL068530027 on the hour with respective periods of the 95, 50, 186SL068530028 and 5% amplitude point of the filter response at 186SL068530029 623.6, 177.0, and 103.7 minutes;(1987-5/1989) 186SL068530030 three-point Hanning filter centered on the hour; 186SL068530031 (5/1989-1991) spot sample on the hour 186SL068530032 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL068530033 centered on noon applied to the hourly data 186SL068530034 with respective periods of the 95, 50, and 5% 186SL068530035 amplitude points at 124.0, 60.2, and 40.2 hours 186SL068530036 Monthly: Simple average of all daily values; calculated if 186SL068530037 7 or fewer days are missing 186SL068530038Span of data : 29 Oct 1975 - 31 Dec 1991 186SL068530039Gaps > 1 mon : 1 Aug - 24 Nov 1978; 1 Nov - 6 Dec 1979; 186SL068530040 10 Nov 1983 - 11 Feb 1984; 20 Mar - 1 Sep 1987 186SL068530041Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL068530042Units : millimeters Missing Data Flag :99999 186SL068530043Refernce Levl: All heights have been referred to the station tide 186SL068530044 staff zero which is linked to fixed bench marks 186SL068530045Comment : The site was moved in March 1989 to 186SL068530046 Latitude: 18 08.2S, Longitude: 178 25.6E and 186SL068530047 is maintained by NOS. Based on an overlap of 186SL068530048 March-May 1989, a constant was determined for 186SL068530049 relating the NOS data to the historic tide staff 186SL068530050 zero. A constant of (-10347 mm) was added to 186SL068530051 the data as provided by NOS. The data from the 186SL068530052 L&S ADR gauge begin on 01 June, 1989. A common 186SL068530053 bench mark is also available between the two 186SL068530054 time periods for comparisons of geodetic surveys. 186SL068530055 Otherwise, the daily and monthly means agree 186SL068530056 well with an adjacent station, Noumea, New 186SL068530057 Caledonia and reveal no obvious changes in the 186SL068530058 reference level. 186SL068530059 186SL068530060 CI MISSING REPLACED GAPS QUESTIONABLE 186SL068530061YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL068530062---- --- -------------------- --------------- -------------------- 186SL0685300631975 17 none none none 186SL0685300641976 99 58-59 none none 186SL0685300651977 98 13-17,129-132 none 12,18-19 186SL0685300661978 67 131-134,213-328 none 115,127 186SL0685300671979 83 1-16,273-284, none 35,162-171,179-180 186SL068530068 305-340 186SL0685300691980 84 2-8,17-20,22-29, none none 186SL068530070 32-50,93-111, 186SL068530071 351-353 186SL0685300721981 90 61-77,104-112, none 125-126 186SL068530073 170-172,287-292, 186SL068530074 314-316 186SL0685300751982 98 7-11,68-69 none none 186SL0685300761983 86 314-365 none none 186SL0685300771984 89 1-42 none none 186SL0685300781985 93 17-27,34-36, none none 186SL068530079 39-48,57-59 186SL0685300801986 99 362-365 none none 186SL0685300811987 52 1-5,79-244, none none 186SL068530082 355-357 186SL0685300831988 98 77-82,137-140 none none 186SL0685300841989 100 none (17)353-(09)355 none 186SL0685300851990 100 none (13)037-(23)037 none 186SL0685300861991 100 none none none 186SL068530087 186SL068530088 QUALITY ASSESSMENT POLICY 186SL068530089 186SL068530090 The quality assessment is mostly based on the residuals 186SL068530091 (observed data minus predicted tides) of the hourly data. This 186SL068530092 assessment also applies to the daily and monthly data since 186SL068530093 they were derived from the quality-controlled hourly data. 186SL068530094 186SL068530095 The following abbreviations are used in the assessment: 186SL068530096 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL068530097 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL068530098 research program; NODC - National Oceanographic Data Center; 186SL068530099 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL068530100 Gaps > 1 mon - missing data in a span greater than one month; 186SL068530101 Refernce - reference. 186SL068530102 186SL068530103 The following corrections are made to the hourly data 186SL068530104 prior to this assessment: 186SL068530105 1) Gaps or obviously wrong data points in a span less than 186SL068530106 25 hours are filled by the predicted tide method*. 186SL068530107 2) Timing errors of exact increments of an hour are corrected 186SL068530108 by shifting the data. 186SL068530109 3) Reference level shifts are only corrected after information 186SL068530110 from tide staff readings or comparative readings with a fixed 186SL068530111 bench mark are checked to verify that the shift was not a 186SL068530112 natural event. If comparative readings are missing or 186SL068530113 incomplete, comparisons of the data with nearby stations 186SL068530114 may warrant the adjustment of some obvious shifts. 186SL068530115 4) Data with unresolved datum shifts are not disseminated. 186SL068530116 However, if sufficient time spans of data are available before 186SL068530117 or after the year(s) with the unresolved shift(s), a subset of 186SL068530118 quality assured data is made available. Thus, the Span field 186SL068530119 in the Quality Assessment may not match the span of the 186SL068530120 distribution data set. As the questionable datum shifts are 186SL068530121 resolved, the data set will be updated. Although this policy 186SL068530122 adds some complexity, it allows more rapid dissemination of 186SL068530123 at least the quality assured years. 186SL068530124 186SL068530125 For each year, the following information is documented from 186SL068530126 the quality-controlled hourly data with dates given as the nth 186SL068530127 day of the year starting from 1 January: 186SL068530128 1) a Completeness Index (CI) based on the percentage of hours 186SL068530129 with available data, 186SL068530130 2) a list of gaps longer than a day, 186SL068530131 3) a summary of days with consecutive missing or obviously 186SL068530132 wrong data in a time span longer than 6 but less than 25 186SL068530133 hours that have been replaced, with hours in parentheses, and 186SL068530134 4) a summary of days with questionable fluctuations in the 186SL068530135 residual series. Fluctuations within the residuals are 186SL068530136 considered significant and are noted if they are greater than 186SL068530137 25 cm. This policy has changed slightly as of October 1992: 186SL068530138 only suspicious fluctuations due to obvious instrumentation 186SL068530139 problems are noted. Minor timing drifts are no longer 186SL068530140 included in the list of questionable days. 186SL068530141 186SL068530142 Note : If the predicted tides poorly model the observed heights 186SL068530143 due to the inability of the tidal analysis to completely resolv 186SL068530144 the non-linear shallow water effects, the residuals are not 186SL068530145 suitable for assessing the data quality. Instead, a subjective 186SL068530146 comment on the quality of the data is provided. 186SL068530147 186SL068530148 *The predicted tides are obtained with the use of a harmonic 186SL068530149 analysis program (Foreman, 1977) which is executed on a year 186SL068530150 of apparently good data for a given station. The Predicted 186SL068530151 Tide Method for filling gaps consists of statistically 186SL068530152 comparing the predicted tides to the observed data and 186SL068530153 shifting the predicted tides in time to correct for timing 186SL068530154 differences. Then the linear interpolation between hourly 186SL068530155 values at the end points of the gap in the residual series is 186SL068530156 added to the corresponding corrected predicted tide data to 186SL068530157 obtain interpolated values over the span of the gap. 186SL068530158 186SL068530159 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL068530160 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL068530161 186SL068530162 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL068530163 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL068530164 Victoria B.C. Pacific Marine Science Report 77-10. 186SL068530165 186SL06856 19751 999999999999999999999999999999999999999999999999 186SL06856 19752 99999999999999999999999999999999 1208000 1206000 186SL06856 19761 1287000 1273010 1268000 1321000 1241000 1178000 186SL06856 19762 1172000 1184000 1217000 1232000 1230000 1265000 186SL06856 19771 1258050 1253000 1280000 1207000 1160040 1171000 186SL06856 19772 1176000 1166000 1148000 1113000 1142000 1171000 186SL06856 19781 1201000 1191000 1121000 1086000 1087040 1073000 186SL06856 19782 107901099999999999999999999999999999999 1099000 186SL06856 19791 99999999 1108000 1213000 1122000 1118000 1110000 186SL06856 19792 1073000 1118000 11320109999999999999999 1138060 186SL06856 19801 9999999999999999 121700099999999 1073000 1120000 186SL06856 19802 1118000 1095000 1104000 1136000 1141000 1172030 186SL06856 19811 1225000 12430009999999999999999 1116000 1147030 186SL06856 19812 1133000 1135000 1157000 1182060 1193030 1192000 186SL06856 19821 1236060 1214000 1233030 1214000 1163000 1229000 186SL06856 19822 1201000 1200000 1170000 1167000 1227000 1238000 186SL06856 19831 1260000 1227000 1168000 1124000 1118000 1116000 186SL06856 19832 1109000 1060000 1087000 11010009999999999999999 186SL06856 19841 9999999999999999 1146000 1092000 1072000 1091000 186SL06856 19842 1145000 1186000 1190000 1181000 1227000 1266000 186SL06856 19851 9999999999999999 1211000 1182000 1175000 1139000 186SL06856 19852 1137000 1161000 1231000 1265000 1285000 1265000 186SL06856 19861 1278000 1202000 1184000 1172000 1080000 1101000 186SL06856 19862 1096000 1140000 1146000 1125000 1215000 1237050 186SL06856 19871 1107060 124700099999999999999999999999999999999 186SL06856 19872 9999999999999999 1084010 1154000 1239000 1244030 186SL06856 19881 1194000 1254000 1256050 1229000 1157040 1103000 186SL06856 19882 1108000 1113000 1180000 1276000 1245000 1286000 186SL06856 19891 1261000 1246000 1248000 1270000 1308000 1278000 186SL06856 19892 1306000 1325000 1330000 1334000 1333000 1290000 186SL06856 19901 1347000 1312000 1344000 1257000 1219000 1239000 186SL06856 19902 1231000 1251000 1279000 1239000 1332000 1291000 186SL06856 19911 1322000 1376000 1334000 1289000 1243000 1257000 186SL06856 19912 1276000 1287000 1302000 1314000 1307000 1326000