186SL0863110177101 005B 19740425 19931231 0706N 17122E 2 00000R 0000 MM 186SL0863210177101 Majuro-B Rep. Marshall I. TOGA Sea Level Center 186SL086330001 186SL086330002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL086330003 by the 186SL086330004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL086330005 JOINT ARCHIVE FOR SEA LEVEL 186SL086330006 186SL086330007Station : Majuro-B Latitude: 07 06.4N 186SL086330008Country : Republic of Marshall Is. Longitude: 171 22.4E 186SL086330009JASL # : 005B Time Meridian: 180E (GMT + 12 hr) 186SL086330010GLOSS # : 112 TOGA #: P043 NODC #: 10177101 186SL086330011Contributor : TOGA Sea Level Center 186SL086330012 1000 Pope Rd. MSB 317 186SL086330013 Honolulu, Hawaii 96822 186SL086330014Originator : Dept. of Oceanography 186SL086330015 University of Hawaii 186SL086330016 1000 Pope Rd. MSB 317 186SL086330017 Honolulu, Hawaii 96822 186SL086330018Original Data: digital 186SL086330019Instrmnt Type: 1. (Apr 1974-present) Leupold and Stevens 186SL086330020 Analog-to-Digital Recorder (ADR); 186SL086330021 2. (Aug 1983-present) Handar Encoder (ENC) 186SL086330022 Primary gauge: ADR: 1974-90, ENC: 1991-93 186SL086330023Digitzd Intvl: 15 (ADR); 3 or 4 (ENC) minutes 186SL086330024Present Data : Hourly, daily, and monthly values obtained by: 186SL086330025 Hourly : (pre-1987) Nine-point triangular filter centered 186SL086330026 on the hour with respective periods of the 95, 50, 186SL086330027 and 5% amplitude point of the filter response at 186SL086330028 623.6, 177.0, and 103.7 minutes;(1987+) three-point 186SL086330029 Hanning filter centered on the hour 186SL086330030 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL086330031 centered on noon applied to the hourly data 186SL086330032 with respective periods of the 95, 50, and 5% 186SL086330033 amplitude points at 124.0, 60.2, and 40.2 hours 186SL086330034 Monthly: Simple average of all daily values; calculated if 186SL086330035 7 or fewer days are missing 186SL086330036Span of data : 25 Apr 1974 - 31 Dec 1993 186SL086330037Gaps > 1 mon : 08 Sep 1974 - 22 Mar 1975; 16 Mar - 27 Apr 1979; 186SL086330038 31 Mar - 3 Jun 1980 186SL086330039Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL086330040Units : millimeters Missing Data Flag :99999 186SL086330041Refernce Levl: All heights have been referred to the station tide 186SL086330042 staff zero which is linked to fixed bench marks 186SL086330043Comment : The daily and monthly means reveal no apparent 186SL086330044 changes in the reference level and agree with 186SL086330045 Ponape. Timing accuracy was no better than 186SL086330046 plus or minus 7 minutes prior to 1983. 186SL086330047 186SL086330048 CI MISSING REPLACED GAPS QUESTIONABLE 186SL086330049YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL086330050---- --- -------------------- --------------- -------------------- 186SL0863300511974 37 251-365 none none 186SL0863300521975 72 1-81,105-120, none 84-85,88-89,98-99, 186SL086330053 126-129,258-259 102,145-146,175, 186SL086330054 188-192 186SL0863300551976 97 255-257,266-270, none 1-4,16-17,47-49,161- 186SL086330056 306-308 165,180,190-196,237- 186SL086330057 242,254,282,353-362 186SL0863300581977 100 none none 18-23,32-40,79-85, 186SL086330059 89-90,121-126,136- 186SL086330060 142,147-151,179-181, 186SL086330061 208-213,238-241,269- 186SL086330062 272,283-288,295-304, 186SL086330063 363 186SL0863300641978 97 60-69 none 8-12,21-24,35-40,52- 186SL086330065 55,71-73,244-249, 186SL086330066 302-305,315-323,329- 186SL086330067 335,344-352,362-365 186SL0863300681979 86 75-117,262-269 none 1-3,9-11,56-63,142- 186SL086330069 145,172-178,229,365 186SL0863300701980 82 91-155 none 1-3,27-35,43-51,59- 186SL086330071 68,73-80 186SL0863300721981 100 none none 64-70,75-84,179-183, 186SL086330073 198-199,209-215,239- 186SL086330074 244,268-273,297-303, 186SL086330075 314-318 186SL0863300761982 99 166-167 none 7-11,25,37-41,66-71, 186SL086330077 229-233,289-291, 186SL086330078 317-319 186SL0863300791983 100 none none 1-5,25-34,43-49,55- 186SL086330080 61,84-89 186SL0863300811984 100 none none none 186SL0863300821985 100 none none none 186SL0863300831986 100 none none none 186SL0863300841987 100 none none none 186SL0863300851988 92 6-11,339-365 none 48-50,61-65,77-80, 186SL086330086 268-269,300-302 186SL0863300871989 100 none none none 186SL0863300881990 100 none none none 186SL0863300891991 100 none none none 186SL0863300901992 100 none none none 186SL0863300911993 100 none none none 186SL086330092 186SL086330093 QUALITY ASSESSMENT POLICY 186SL086330094 186SL086330095 The quality assessment is mostly based on the residuals 186SL086330096 (observed data minus predicted tides) of the hourly data. This 186SL086330097 assessment also applies to the daily and monthly data since 186SL086330098 they were derived from the quality-controlled hourly data. 186SL086330099 186SL086330100 The following abbreviations are used in the assessment: 186SL086330101 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL086330102 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL086330103 research program; NODC - National Oceanographic Data Center; 186SL086330104 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL086330105 Gaps > 1 mon - missing data in a span greater than one month; 186SL086330106 Refernce - reference. 186SL086330107 186SL086330108 The following corrections are made to the hourly data 186SL086330109 prior to this assessment: 186SL086330110 1) Gaps or obviously wrong data points in a span less than 186SL086330111 25 hours are filled by the predicted tide method*. 186SL086330112 2) Timing errors of exact increments of an hour are corrected 186SL086330113 by shifting the data. 186SL086330114 3) Reference level shifts are only corrected after information 186SL086330115 from tide staff readings or comparative readings with a fixed 186SL086330116 bench mark are checked to verify that the shift was not a 186SL086330117 natural event. If comparative readings are missing or 186SL086330118 incomplete, comparisons of the data with nearby stations 186SL086330119 may warrant the adjustment of some obvious shifts. 186SL086330120 4) Data with unresolved datum shifts are not disseminated. 186SL086330121 However, if sufficient time spans of data are available before 186SL086330122 or after the year(s) with the unresolved shift(s), a subset of 186SL086330123 quality assured data is made available. Thus, the Span field 186SL086330124 in the Quality Assessment may not match the span of the 186SL086330125 distribution data set. As the questionable datum shifts are 186SL086330126 resolved, the data set will be updated. Although this policy 186SL086330127 adds some complexity, it allows more rapid dissemination of 186SL086330128 at least the quality assured years. 186SL086330129 186SL086330130 For each year, the following information is documented from 186SL086330131 the quality-controlled hourly data with dates given as the nth 186SL086330132 day of the year starting from 1 January: 186SL086330133 1) a Completeness Index (CI) based on the percentage of hours 186SL086330134 with available data, 186SL086330135 2) a list of gaps longer than a day, 186SL086330136 3) a summary of days with consecutive missing or obviously 186SL086330137 wrong data in a time span longer than 6 but less than 25 186SL086330138 hours that have been replaced, with hours in parentheses, and 186SL086330139 4) a summary of days with questionable fluctuations in the 186SL086330140 residual series. Fluctuations within the residuals are 186SL086330141 considered significant and are noted if they are greater than 186SL086330142 25 cm. This policy has changed slightly as of October 1992: 186SL086330143 only suspicious fluctuations due to obvious instrumentation 186SL086330144 problems are noted. Minor timing drifts are no longer 186SL086330145 included in the list of questionable days. 186SL086330146 186SL086330147 Note : If the predicted tides poorly model the observed heights 186SL086330148 due to the inability of the tidal analysis to completely resolv 186SL086330149 the non-linear shallow water effects, the residuals are not 186SL086330150 suitable for assessing the data quality. Instead, a subjective 186SL086330151 comment on the quality of the data is provided. 186SL086330152 186SL086330153 *The predicted tides are obtained with the use of a harmonic 186SL086330154 analysis program (Foreman, 1977) which is executed on a year 186SL086330155 of apparently good data for a given station. The Predicted 186SL086330156 Tide Method for filling gaps consists of statistically 186SL086330157 comparing the predicted tides to the observed data and 186SL086330158 shifting the predicted tides in time to correct for timing 186SL086330159 differences. Then the linear interpolation between hourly 186SL086330160 values at the end points of the gap in the residual series is 186SL086330161 added to the corresponding corrected predicted tide data to 186SL086330162 obtain interpolated values over the span of the gap. 186SL086330163 186SL086330164 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL086330165 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL086330166 186SL086330167 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL086330168 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL086330169 Victoria B.C. Pacific Marine Science Report 77-10. 186SL086330170 186SL08636 19741 99999999999999999999999999999999 1111000 1074000 186SL08636 19742 1123000 115300099999999999999999999999999999999 186SL08636 19751 99999999999999999999999999999999 1142040 1097000 186SL08636 19752 1084000 1131000 1220020 1227000 1222000 1105000 186SL08636 19761 1096000 1177000 1163000 1172000 1117000 1073000 186SL08636 19762 1086000 104700099999999 1041000 1052030 1063000 186SL08636 19771 1032000 1174000 1248000 1236000 1192000 1164000 186SL08636 19772 1131000 1101000 1113000 1196000 1167000 1109000 186SL08636 19781 1081000 124101099999999 1209000 1179000 1147000 186SL08636 19782 1124000 1183000 1182000 1165000 1196000 1101000 186SL08636 19791 1137000 11680009999999999999999 1146000 1157000 186SL08636 19792 115500099999999 1157000 1149000 1186000 1160000 186SL08636 19801 1128000 1178000 12010109999999999999999 1080030 186SL08636 19802 1062000 1104000 1209000 1179000 1146000 1137000 186SL08636 19811 1127000 1194000 1206000 1180000 1146000 1174000 186SL08636 19812 1176000 1127000 1185000 1178000 1158000 1188000 186SL08636 19821 1189000 1152000 1177000 1084000 1086000 1086030 186SL08636 19822 1031000 1010000 985000 1098000 993000 858000 186SL08636 19831 985000 1157000 1146000 1164000 1228000 1241000 186SL08636 19832 1252000 1231000 1286000 1279000 1223000 1142000 186SL08636 19841 1164000 1232000 1231000 1145000 1182000 1157000 186SL08636 19842 1137000 1124000 1112000 1219000 1198000 1247000 186SL08636 19851 1122000 1224000 1209000 1175000 1133000 1073000 186SL08636 19852 1096000 1148000 1215000 1220000 1157000 1145000 186SL08636 19861 1245000 1292000 1272000 1184000 1162000 1164000 186SL08636 19862 1161000 1155000 1155000 1130000 1185000 1074000 186SL08636 19871 1031000 1227000 1248000 1188000 1159000 1124000 186SL08636 19872 1136000 1137000 1085000 1115000 1116000 1022000 186SL08636 19881 1041060 1135000 1217000 1286000 1215000 1155000 186SL08636 19882 1137000 1211000 1286000 1310000 135700099999999 186SL08636 19891 1183000 1256000 1186000 1200000 1199000 1169000 186SL08636 19892 1175000 1142000 1181000 1216000 1323000 1237000 186SL08636 19901 1271000 1261000 1247000 1259000 1208000 1206000 186SL08636 19902 1154000 1168000 1196000 1218000 1236000 1159000 186SL08636 19911 1198000 1251000 1234000 1163000 1087000 1089000 186SL08636 19912 1068000 1072000 1116000 1159000 1072000 972000 186SL08636 19921 986000 1095000 1126000 1167000 1134000 1170000 186SL08636 19922 1192000 1187000 1259000 1335000 1201000 1152000 186SL08636 19931 1111000 1152000 1162000 1133000 1135000 1186000 186SL08636 19932 1176000 1139000 1142000 1215000 1172000 1129000