186SL0802133112501 175A 19840101 19921231 3203S 11544E 2 00000R 0000 MM 186SL0802233112501 Fremantle Australia The National Tidal Facility 186SL080230001 186SL080230002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL080230003 by the 186SL080230004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL080230005 JOINT ARCHIVE FOR SEA LEVEL 186SL080230006 186SL080230007Station : Fremantle Latitude: 32 03.0S 186SL080230008Country : Australia Longitude: 115 44.0E 186SL080230009JASL # : 175A Time Meridian: 120E (GMT + 8 hr) 186SL080230010GLOSS # : 053 TOGA #: none NODC #: 33112501 186SL080230011Contributor : The National Tidal Facility 186SL080230012 Flinders University of South Australia 186SL080230013 GPO Box 2100 186SL080230014 Adelaide, 5001, South Australia 186SL080230015 AUSTRALIA 186SL080230016Originator : same 186SL080230017Original Data: analog 186SL080230018Instrmnt Type: Bailey (analog), Leupold Stevens (analog), 186SL080230019 and Steedman (digital); all float and stilling well 186SL080230020Digitzd Intvl: unconfirmed 186SL080230021Present Data : Hourly, daily, and monthly values obtained by: 186SL080230022 Hourly : unconfirmed 186SL080230023 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL080230024 centered on noon applied to the hourly data 186SL080230025 with respective periods of the 95, 50, and 5% 186SL080230026 amplitude points at 124.0, 60.2, and 40.2 hours 186SL080230027 Monthly: Simple average of all daily values; calculated if 186SL080230028 7 or fewer days are missing 186SL080230029Span of data : 01 Jan 1984 - 31 Dec 1992 186SL080230030Gaps > 1 mon : none 186SL080230031Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL080230032Units : millimeters Missing Data Flag :99999 186SL080230033Refernce Levl: The sea level heights are referred to the zero 186SL080230034 point assigned to the tide staff. Bench mark 186SL080230035 information is available upon request from the 186SL080230036 contributors. 186SL080230037Comment : The daily and monthly values do not reveal any 186SL080230038 obvious reference level shifts and agree moderately 186SL080230039 with the nearest station, Carnarvon. 186SL080230040 186SL080230041 SPECIAL NOTE FROM THE DATA CONTRIBUTORS: 186SL080230042 186SL080230043 Supply of sea level data subject to the following 186SL080230044 conditions: 186SL080230045 186SL080230046 i) When any data supplied by the National Tidal 186SL080230047 Facility is used in any publication or report, the 186SL080230048 origin of such data shall be acknowledged in that 186SL080230049 publication or report in the following approved 186SL080230050 form:-- 186SL080230051 186SL080230052 "Tidal {predictions) for {port} {are} supplied 186SL080230053 {constants} {station} {is} 186SL080230054 {material} {...} 186SL080230055 186SL080230056 by the National Tidal Facility, The Flinders 186SL080230057 University of South Australia, Copyright reserved." 186SL080230058 186SL080230059 ii) All material is supplied in good faith and is 186SL080230060 believed to be correct. It is supplied on the 186SL080230061 condition that no warranty is given in relation 186SL080230062 thereto, that no responsibility or liability for 186SL080230063 errors or omissions is, or will be, accepted and 186SL080230064 that the recipient will hold the Flinders Univer- 186SL080230065 sity of South Australia and the National Tidal 186SL080230066 Facility free from all such responsibility or 186SL080230067 liability and from all loss or damage incurred as 186SL080230068 a consequence of any error or omission. 186SL080230069 186SL080230070 iii) The acceptance of material and computations 186SL080230071 from the National Tidal Facility of the Flinders 186SL080230072 University of South Australia will be deemed to 186SL080230073 include acceptance of the conditions of supply. 186SL080230074 186SL080230075 CI MISSING REPLACED GAPS QUESTIONABLE 186SL080230076YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL080230077---- --- -------------------- --------------- -------------------- 186SL0802300781984 100 none none none 186SL0802300791985 100 none none none 186SL0802300801986 100 none none 2,101,200-201 186SL0802300811987 100 none none none 186SL0802300821988 100 none (03)366-(23)366 119,145 186SL0802300831989 99 242-244 (02)260-(01)261 none 186SL0802300841990 98 1-5,241-243, none 363-364 186SL080230085 355-358 186SL0802300861991 92 95-120,352-357 none none 186SL0802300871992 99 243-245 none none 186SL080230088 186SL080230089 QUALITY ASSESSMENT POLICY 186SL080230090 186SL080230091 The quality assessment is mostly based on the residuals 186SL080230092 (observed data minus predicted tides) of the hourly data. This 186SL080230093 assessment also applies to the daily and monthly data since 186SL080230094 they were derived from the quality-controlled hourly data. 186SL080230095 186SL080230096 The following abbreviations are used in the assessment: 186SL080230097 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL080230098 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL080230099 research program; NODC - National Oceanographic Data Center; 186SL080230100 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL080230101 Gaps > 1 mon - missing data in a span greater than one month; 186SL080230102 Refernce - reference. 186SL080230103 186SL080230104 The following corrections are made to the hourly data 186SL080230105 prior to this assessment: 186SL080230106 1) Gaps or obviously wrong data points in a span less than 186SL080230107 25 hours are filled by the predicted tide method*. 186SL080230108 2) Timing errors of exact increments of an hour are corrected 186SL080230109 by shifting the data. 186SL080230110 3) Reference level shifts are only corrected after information 186SL080230111 from tide staff readings or comparative readings with a fixed 186SL080230112 bench mark are checked to verify that the shift was not a 186SL080230113 natural event. If comparative readings are missing or 186SL080230114 incomplete, comparisons of the data with nearby stations 186SL080230115 may warrant the adjustment of some obvious shifts. 186SL080230116 4) Data with unresolved datum shifts are not disseminated. 186SL080230117 However, if sufficient time spans of data are available before 186SL080230118 or after the year(s) with the unresolved shift(s), a subset of 186SL080230119 quality assured data is made available. Thus, the Span field 186SL080230120 in the Quality Assessment may not match the span of the 186SL080230121 distribution data set. As the questionable datum shifts are 186SL080230122 resolved, the data set will be updated. Although this policy 186SL080230123 adds some complexity, it allows more rapid dissemination of 186SL080230124 at least the quality assured years. 186SL080230125 186SL080230126 For each year, the following information is documented from 186SL080230127 the quality-controlled hourly data with dates given as the nth 186SL080230128 day of the year starting from 1 January: 186SL080230129 1) a Completeness Index (CI) based on the percentage of hours 186SL080230130 with available data, 186SL080230131 2) a list of gaps longer than a day, 186SL080230132 3) a summary of days with consecutive missing or obviously 186SL080230133 wrong data in a time span longer than 6 but less than 25 186SL080230134 hours that have been replaced, with hours in parentheses, and 186SL080230135 4) a summary of days with questionable fluctuations in the 186SL080230136 residual series. Fluctuations within the residuals are 186SL080230137 considered significant and are noted if they are greater than 186SL080230138 25 cm. This policy has changed slightly as of October 1992: 186SL080230139 only suspicious fluctuations due to obvious instrumentation 186SL080230140 problems are noted. Minor timing drifts are no longer 186SL080230141 included in the list of questionable days. 186SL080230142 186SL080230143 Note : If the predicted tides poorly model the observed heights 186SL080230144 due to the inability of the tidal analysis to completely resolv 186SL080230145 the non-linear shallow water effects, the residuals are not 186SL080230146 suitable for assessing the data quality. Instead, a subjective 186SL080230147 comment on the quality of the data is provided. 186SL080230148 186SL080230149 *The predicted tides are obtained with the use of a harmonic 186SL080230150 analysis program (Foreman, 1977) which is executed on a year 186SL080230151 of apparently good data for a given station. The Predicted 186SL080230152 Tide Method for filling gaps consists of statistically 186SL080230153 comparing the predicted tides to the observed data and 186SL080230154 shifting the predicted tides in time to correct for timing 186SL080230155 differences. Then the linear interpolation between hourly 186SL080230156 values at the end points of the gap in the residual series is 186SL080230157 added to the corresponding corrected predicted tide data to 186SL080230158 obtain interpolated values over the span of the gap. 186SL080230159 186SL080230160 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL080230161 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL080230162 186SL080230163 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL080230164 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL080230165 Victoria B.C. Pacific Marine Science Report 77-10. 186SL080230166 186SL08026 19841 672000 702000 729000 880000 1002000 919000 186SL08026 19842 802000 749000 702000 733000 669000 638000 186SL08026 19851 582000 848000 737000 873000 819000 890000 186SL08026 19852 793000 743000 666000 598000 665000 631000 186SL08026 19861 686000 714000 762000 713000 820000 817000 186SL08026 19862 759000 685000 630000 600000 604000 538000 186SL08026 19871 578000 523000 694000 738000 678000 840000 186SL08026 19872 773000 673000 605000 565000 583000 613000 186SL08026 19881 585000 703000 737000 795000 901000 925000 186SL08026 19882 825000 806000 845000 781000 698000 721000 186SL08026 19891 763000 829000 802000 907000 913000 850000 186SL08026 19892 827000 758020 713010 686000 685000 631000 186SL08026 19901 664050 762000 737000 752000 775000 763000 186SL08026 19902 755000 662020 665000 609000 611000 634040 186SL08026 19911 606000 572000 71500099999999 824000 893000 186SL08026 19912 859000 699000 640000 618000 594000 599060 186SL08026 19921 603000 655000 675000 766000 793000 901000 186SL08026 19922 771000 753020 605010 599000 663000 603000