186SL0670150090001 003A 19680601 19771231 0026S 09017W 2 00000R 0000 MM 186SL0670250090001 Baltra-A Ecuador National Ocean Service 186SL067030001 186SL067030002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL067030003 by the 186SL067030004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL067030005 JOINT ARCHIVE FOR SEA LEVEL 186SL067030006 186SL067030007Station : Baltra-A,Galapagos Is. Latitude: 00 26.1S 186SL067030008Country : Ecuador Longitude: 090 17.1W 186SL067030009JASL # : 003A Time Meridian: 090W (GMT - 6 hr) 186SL067030010GLOSS # : 169 TOGA #: P082 NODC #: 50090001 186SL067030011Contributor : National Ocean Service (NOS) 186SL067030012 National Ocean. and Atmos. Administration (NOAA) 186SL067030013 Rockville, Maryland 20852 186SL067030014 ( standard data (1968-1977) ) 186SL067030015 and 186SL067030016 TOGA Sea Level Center 186SL067030017 1000 Pope Rd. MSB 317 186SL067030018 Honolulu, Hawaii 96822 186SL067030019 ( ADR data (1974-1976) ) 186SL067030020Originator : same 186SL067030021Original Data: analog (standard); digital (ADR) 186SL067030022Instrmnt Type: standard mechanical (1968-1977); Fisher and Porter 186SL067030023 analog-to-digital recorder (ADR) (1974-1976) 186SL067030024Digitzd Intvl: hourly (standard); 15-minute (ADR) 186SL067030025Present Data : Hourly, daily, and monthly values obtained by: 186SL067030026 Hourly : The original digitizing interval was hourly 186SL067030027 (standard); Nine-point triangular filter centered 186SL067030028 on the hour with respective periods of the 95, 50, 186SL067030029 and 5% amplitude point of the filter response at 186SL067030030 623.6, 177.0, and 103.7 minutes (ADR) 186SL067030031 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL067030032 centered on noon applied to the hourly data 186SL067030033 with respective periods of the 95, 50, and 5% 186SL067030034 amplitude points at 124.0, 60.2, and 40.2 hours 186SL067030035 Monthly: Simple average of all daily values; calculated if 186SL067030036 7 or fewer days are missing 186SL067030037Span of data : 01 Jun 1968 - 31 Dec 1977 186SL067030038Gaps > 1 mon : 01 Jan - 02 Feb 1976, 01 Jul - 09 Aug 1976, 186SL067030039 01 Dec 1976 - 02 Jan 1977 186SL067030040Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL067030041Units : millimeters Missing Data Flag :99999 186SL067030042Refernce Levl: All heights have been referred to the station tide 186SL067030043 staff zero which is linked to fixed bench marks 186SL067030044Comment : The following gaps in the analog data were filled 186SL067030045 with ADR data: 28 Aug 1974 - 15 Jun 1975, 02 Feb - 186SL067030046 01 May 1976, and 01 Sep - 31 Nov 1976. The daily 186SL067030047 and monthly means agree reasonably well with La 186SL067030048 Libertad, Ecuador. This station is distinguished 186SL067030049 from station Baltra-B because the data have not 186SL067030050 been levelled to common bench marks. 186SL067030051 186SL067030052 CI MISSING REPLACED GAPS QUESTIONABLE 186SL067030053YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL067030054---- --- -------------------- --------------- -------------------- 186SL0670300551968 58 none none 192,359-361 186SL0670300561969 99 1-2 (19)054-(07)055 65-68,302-304 186SL067030057 (22)097-(06)098 186SL067030058 (00)139-(23)139 186SL067030059 (18)197-(16)198 186SL067030060 (22)255-(21)256 186SL067030061 (16)279-(06)280 186SL0670300621970 98 350-358 (23)038-(22)039 41-42,360-362 186SL067030063 (00)092-(08)092 186SL067030064 (16)096-(15)097 186SL067030065 (14)107-(21)107 186SL067030066 (00)329-(11)329 186SL0670300671971 95 31-37,52-55, (13)030-(21)030 27-28,52-53,55-56 186SL067030068 76-78,82-85, (00)069-(22)069 186SL067030069 89-90 (02)070-(19)070 186SL067030070 (03)071-(14)071 186SL067030071 (05)072-(20)072 186SL067030072 (22)072-(20)073 186SL067030073 (08)075-(17)075 186SL067030074 (09)080-(21)080 186SL067030075 (02)081-(19)081 186SL067030076 (11)087-(20)087 186SL067030077 (06)088-(01)089 186SL067030078 (23)157-(16)158 186SL067030079 (03)222-(16)222 186SL067030080 (04)223-(17)223 186SL067030081 (07)293-(17)293 186SL0670300821972 100 none (05)031-(15)031 281-285,289 186SL0670300831973 94 1-2,176-188, (01)068-(14)068 68-75,104,116,122- 186SL067030084 210-211,213-214, (05)069-(22)069 123,127-129,146-149, 186SL067030085 362-365 (06)091-(18)091 153-161,274,284,290- 186SL067030086 (03)100-(14)100 291 186SL067030087 (17)106-(23)106 186SL067030088 (22)130-(14)131 186SL067030089 (16)152-(15)153 186SL067030090 (05)242-(15)242 186SL067030091 (04)286-(19)286 186SL067030092 (06)335-(14)335 186SL0670300931974 100 1 (06)032-(14)032 127-132,199-207 186SL067030094 (18)099-(02)100 186SL067030095 (18)115-(03)116 186SL067030096 (06)116-(15)116 186SL067030097 (06)152-(16)152 186SL0670300981975 94 115-117,293-314 (19)271-(13)272 117,172-173,192,218- 186SL067030099 219,230-232,289-290, 186SL067030100 330,350,355,360-362, 186SL067030101 365 186SL0670301021976 71 1-33,167-169, (06)149-(05)150 164-167,170-171, 186SL067030103 183-222,283-286, (06)180-(05)181 176-178 186SL067030104 336-365 186SL0670301051977 83 1-2,3-9,31-33, (06)129-(05)130 45-56,61-67,70,94- 186SL067030106 158-160,184-186, (06)163-(05)164 107,120,155-156,181- 186SL067030107 207-211,213-214, (06)180-(05)181 182,189,193-196,199- 186SL067030108 230-245,251-256, (06)247-(05)248 200,205-206,226-230, 186SL067030109 258-263,282-286, (06)276-(05)277 289-290 186SL067030110 326-329,337-340, (06)279-(05)280 186SL067030111 345-348,351-354, (06)335-(05)336 186SL067030112 360-364 186SL067030113 186SL067030114 QUALITY ASSESSMENT POLICY 186SL067030115 186SL067030116 The quality assessment is mostly based on the residuals 186SL067030117 (observed data minus predicted tides) of the hourly data. This 186SL067030118 assessment also applies to the daily and monthly data since 186SL067030119 they were derived from the quality-controlled hourly data. 186SL067030120 186SL067030121 The following abbreviations are used in the assessment: 186SL067030122 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL067030123 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL067030124 research program; NODC - National Oceanographic Data Center; 186SL067030125 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL067030126 Gaps > 1 mon - missing data in a span greater than one month; 186SL067030127 Refernce - reference. 186SL067030128 186SL067030129 The following corrections are made to the hourly data 186SL067030130 prior to this assessment: 186SL067030131 1) Gaps or obviously wrong data points in a span less than 186SL067030132 25 hours are filled by the predicted tide method*. 186SL067030133 2) Timing errors of exact increments of an hour are corrected 186SL067030134 by shifting the data. 186SL067030135 3) Reference level shifts are only corrected after information 186SL067030136 from tide staff readings or comparative readings with a fixed 186SL067030137 bench mark are checked to verify that the shift was not a 186SL067030138 natural event. If comparative readings are missing or 186SL067030139 incomplete, comparisons of the data with nearby stations 186SL067030140 may warrant the adjustment of some obvious shifts. 186SL067030141 4) Data with unresolved datum shifts are not disseminated. 186SL067030142 However, if sufficient time spans of data are available before 186SL067030143 or after the year(s) with the unresolved shift(s), a subset of 186SL067030144 quality assured data is made available. Thus, the Span field 186SL067030145 in the Quality Assessment may not match the span of the 186SL067030146 distribution data set. As the questionable datum shifts are 186SL067030147 resolved, the data set will be updated. Although this policy 186SL067030148 adds some complexity, it allows more rapid dissemination of 186SL067030149 at least the quality assured years. 186SL067030150 186SL067030151 For each year, the following information is documented from 186SL067030152 the quality-controlled hourly data with dates given as the nth 186SL067030153 day of the year starting from 1 January: 186SL067030154 1) a Completeness Index (CI) based on the percentage of hours 186SL067030155 with available data, 186SL067030156 2) a list of gaps longer than a day, 186SL067030157 3) a summary of days with consecutive missing or obviously 186SL067030158 wrong data in a time span longer than 6 but less than 25 186SL067030159 hours that have been replaced, with hours in parentheses, and 186SL067030160 4) a summary of days with questionable fluctuations in the 186SL067030161 residual series. Fluctuations within the residuals are 186SL067030162 considered significant and are noted if they are greater than 186SL067030163 25 cm. This policy has changed slightly as of October 1992: 186SL067030164 only suspicious fluctuations due to obvious instrumentation 186SL067030165 problems are noted. Minor timing drifts are no longer 186SL067030166 included in the list of questionable days. 186SL067030167 186SL067030168 Note : If the predicted tides poorly model the observed heights 186SL067030169 due to the inability of the tidal analysis to completely resolv 186SL067030170 the non-linear shallow water effects, the residuals are not 186SL067030171 suitable for assessing the data quality. Instead, a subjective 186SL067030172 comment on the quality of the data is provided. 186SL067030173 186SL067030174 *The predicted tides are obtained with the use of a harmonic 186SL067030175 analysis program (Foreman, 1977) which is executed on a year 186SL067030176 of apparently good data for a given station. The Predicted 186SL067030177 Tide Method for filling gaps consists of statistically 186SL067030178 comparing the predicted tides to the observed data and 186SL067030179 shifting the predicted tides in time to correct for timing 186SL067030180 differences. Then the linear interpolation between hourly 186SL067030181 values at the end points of the gap in the residual series is 186SL067030182 added to the corresponding corrected predicted tide data to 186SL067030183 obtain interpolated values over the span of the gap. 186SL067030184 186SL067030185 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL067030186 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL067030187 186SL067030188 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL067030189 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL067030190 Victoria B.C. Pacific Marine Science Report 77-10. 186SL067030191 186SL06706 19681 9999999999999999999999999999999999999999 2239010 186SL06706 19682 2296000 2259000 2242000 2294000 2287000 2337000 186SL06706 19691 2303020 2335000 2397000 2385000 2344000 2288000 186SL06706 19692 2245000 2224000 2278000 2270000 2309000 2304000 186SL06706 19701 2261000 2257000 2224000 2239000 2213000 2173000 186SL06706 19702 2229000 2238000 2246000 2254000 221800099999999 186SL06706 19711 21900109999999999999999 2258000 2197000 2232000 186SL06706 19712 2243000 2189000 2214000 2233000 2207000 2242000 186SL06706 19721 2290000 2357000 2393000 2415000 2423000 2427000 186SL06706 19722 2398000 2341000 2338000 2332000 2423000 2437000 186SL06706 19731 2396020 2254000 2253000 2276000 2219000 2188060 186SL06706 19732 99999999 2246020 2199000 2233000 2217000 2199040 186SL06706 19741 2222010 2284000 2318000 2317000 2295000 2378000 186SL06706 19742 2280000 2216000 2192000 2198000 2188000 2180000 186SL06706 19751 2306000 2370000 2389000 2333020 2240000 2251000 186SL06706 19752 2249000 2235000 22350009999999999999999 2213000 186SL06706 19761 99999999 2252010 2304000 2349000 2384000 2410030 186SL06706 19762 9999999999999999 2301000 2310040 233700099999999 186SL06706 19771 99999999 2231020 2189000 2183000 2208000 2202030 186SL06706 19772 999999999999999999999999 2230050 225704099999999