186SL0835173012601 218B 19761006 19911231 3238N 01654W 2 00000R 0000 MM 186SL0835273012601 Funchal-B Portugal Inst. Hidro. Marinha 186SL083530001 186SL083530002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL083530003 by the 186SL083530004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL083530005 JOINT ARCHIVE FOR SEA LEVEL 186SL083530006 186SL083530007Station : Funchal-B,Madeira Is. Latitude: 32 38.4N 186SL083530008Country : Portugal Longitude: 016 54.4W 186SL083530009JASL # : 218B Time Meridian: 000W (GMT) 186SL083530010GLOSS # : 250 TOGA #: none NODC #: 73012601 186SL083530011Contributor : Instituto Hidrografico Marinha 186SL083530012 Rua das Trinas 186SL083530013 49-P-1296 Lisboa Codex 186SL083530014 Lisbon 186SL083530015 PORTUGAL 186SL083530016Originator : same 186SL083530017Original Data: analog 186SL083530018Instrmnt Type: Float and well, A.OTT 186SL083530019Digitzd Intvl: hourly 186SL083530020Present Data : Hourly, daily, and monthly values obtained by: 186SL083530021 Hourly : the original data were hourly 186SL083530022 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL083530023 centered on noon applied to the hourly data 186SL083530024 with respective periods of the 95, 50, and 5% 186SL083530025 amplitude points at 124.0, 60.2, and 40.2 hours 186SL083530026 Monthly: Simple average of all daily values; calculated if 186SL083530027 7 or fewer days are missing 186SL083530028Span of data : 06 Oct 1976 - 31 Dec 1991 186SL083530029Gaps > 1 mon : 05 Apr 1978 - 15 Mar 1979;4 Jul 1979 - 12 Nov 1981 186SL083530030 17 Feb 1982 - 27 Apr 1983;9 Nov 1983 - 12 May 1986 186SL083530031 30 Jul 1987 - 07 Oct 1987 186SL083530032Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL083530033Units : millimeters Missing Data Flag :99999 186SL083530034Refernce Levl: All heights have been referred to the station tide 186SL083530035 staff zero which is linked to fixed bench marks 186SL083530036Comment : The series contains large gaps. The daily and 186SL083530037 monthly means do not reveal any obvious reference 186SL083530038 level shifts. 186SL083530039 186SL083530040 CI MISSING REPLACED GAPS QUESTIONABLE 186SL083530041YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL083530042---- --- -------------------- --------------- -------------------- 186SL0835300431976 24 none none none 186SL0835300441977 100 none none 360-363 186SL0835300451978 26 95-365 none 1-2 186SL0835300461979 28 1-75,136-144, none 78-81,92-95,102-103 186SL083530047 185-365 186SL0835300481980 0 1-366 none none 186SL0835300491981 9 1-317,330-345 none none 186SL0835300501982 13 48-365 none none 186SL0835300511983 54 1-118,313-365 none none 186SL0835300521984 0 1-366 none none 186SL0835300531985 0 1-365 none none 186SL0835300541986 64 1-133 none 142-145 186SL0835300551987 81 211-280 none none 186SL0835300561988 99 3-8 none none 186SL0835300571989 100 none (00)351-(23)351 none 186SL0835300581990 100 none none none 186SL0835300591991 96 80-83,171-174,295- none none 186SL083530060 298,315-321 186SL083530061 186SL083530062 QUALITY ASSESSMENT POLICY 186SL083530063 186SL083530064 The quality assessment is mostly based on the residuals 186SL083530065 (observed data minus predicted tides) of the hourly data. This 186SL083530066 assessment also applies to the daily and monthly data since 186SL083530067 they were derived from the quality-controlled hourly data. 186SL083530068 186SL083530069 The following abbreviations are used in the assessment: 186SL083530070 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL083530071 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL083530072 research program; NODC - National Oceanographic Data Center; 186SL083530073 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL083530074 Gaps > 1 mon - missing data in a span greater than one month; 186SL083530075 Refernce - reference. 186SL083530076 186SL083530077 The following corrections are made to the hourly data 186SL083530078 prior to this assessment: 186SL083530079 1) Gaps or obviously wrong data points in a span less than 186SL083530080 25 hours are filled by the predicted tide method*. 186SL083530081 2) Timing errors of exact increments of an hour are corrected 186SL083530082 by shifting the data. 186SL083530083 3) Reference level shifts are only corrected after information 186SL083530084 from tide staff readings or comparative readings with a fixed 186SL083530085 bench mark are checked to verify that the shift was not a 186SL083530086 natural event. If comparative readings are missing or 186SL083530087 incomplete, comparisons of the data with nearby stations 186SL083530088 may warrant the adjustment of some obvious shifts. 186SL083530089 4) Data with unresolved datum shifts are not disseminated. 186SL083530090 However, if sufficient time spans of data are available before 186SL083530091 or after the year(s) with the unresolved shift(s), a subset of 186SL083530092 quality assured data is made available. Thus, the Span field 186SL083530093 in the Quality Assessment may not match the span of the 186SL083530094 distribution data set. As the questionable datum shifts are 186SL083530095 resolved, the data set will be updated. Although this policy 186SL083530096 adds some complexity, it allows more rapid dissemination of 186SL083530097 at least the quality assured years. 186SL083530098 186SL083530099 For each year, the following information is documented from 186SL083530100 the quality-controlled hourly data with dates given as the nth 186SL083530101 day of the year starting from 1 January: 186SL083530102 1) a Completeness Index (CI) based on the percentage of hours 186SL083530103 with available data, 186SL083530104 2) a list of gaps longer than a day, 186SL083530105 3) a summary of days with consecutive missing or obviously 186SL083530106 wrong data in a time span longer than 6 but less than 25 186SL083530107 hours that have been replaced, with hours in parentheses, and 186SL083530108 4) a summary of days with questionable fluctuations in the 186SL083530109 residual series. Fluctuations within the residuals are 186SL083530110 considered significant and are noted if they are greater than 186SL083530111 25 cm. This policy has changed slightly as of October 1992: 186SL083530112 only suspicious fluctuations due to obvious instrumentation 186SL083530113 problems are noted. Minor timing drifts are no longer 186SL083530114 included in the list of questionable days. 186SL083530115 186SL083530116 Note : If the predicted tides poorly model the observed heights 186SL083530117 due to the inability of the tidal analysis to completely resolv 186SL083530118 the non-linear shallow water effects, the residuals are not 186SL083530119 suitable for assessing the data quality. Instead, a subjective 186SL083530120 comment on the quality of the data is provided. 186SL083530121 186SL083530122 *The predicted tides are obtained with the use of a harmonic 186SL083530123 analysis program (Foreman, 1977) which is executed on a year 186SL083530124 of apparently good data for a given station. The Predicted 186SL083530125 Tide Method for filling gaps consists of statistically 186SL083530126 comparing the predicted tides to the observed data and 186SL083530127 shifting the predicted tides in time to correct for timing 186SL083530128 differences. Then the linear interpolation between hourly 186SL083530129 values at the end points of the gap in the residual series is 186SL083530130 added to the corresponding corrected predicted tide data to 186SL083530131 obtain interpolated values over the span of the gap. 186SL083530132 186SL083530133 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL083530134 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL083530135 186SL083530136 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL083530137 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL083530138 Victoria B.C. Pacific Marine Science Report 77-10. 186SL083530139 186SL08356 19761 999999999999999999999999999999999999999999999999 186SL08356 19762 999999999999999999999999 1614050 1569000 1605000 186SL08356 19771 1570000 1511000 1496000 1510000 1538000 1543000 186SL08356 19772 1537000 1584000 1604000 1596000 1571000 1632000 186SL08356 19781 1527000 1610000 1473000999999999999999999999999 186SL08356 19782 999999999999999999999999999999999999999999999999 186SL08356 19791 999999999999999999999999 152800099999999 1565000 186SL08356 19792 999999999999999999999999999999999999999999999999 186SL08356 19801 999999999999999999999999999999999999999999999999 186SL08356 19802 999999999999999999999999999999999999999999999999 186SL08356 19811 999999999999999999999999999999999999999999999999 186SL08356 19812 999999999999999999999999999999999999999999999999 186SL08356 19821 15740009999999999999999999999999999999999999999 186SL08356 19822 999999999999999999999999999999999999999999999999 186SL08356 19831 99999999999999999999999999999999 1577000 1566000 186SL08356 19832 1591000 1617000 1622000 16250009999999999999999 186SL08356 19841 999999999999999999999999999999999999999999999999 186SL08356 19842 999999999999999999999999999999999999999999999999 186SL08356 19851 999999999999999999999999999999999999999999999999 186SL08356 19852 999999999999999999999999999999999999999999999999 186SL08356 19861 9999999999999999999999999999999999999999 1532000 186SL08356 19862 1562000 1566000 1611000 1571000 1522000 1466000 186SL08356 19871 1542000 1444000 1488000 1502000 1517000 1531000 186SL08356 19872 15730209999999999999999 1634060 1616000 1579000 186SL08356 19881 1473050 1528000 1465000 1502000 1519000 1543000 186SL08356 19882 1569000 1611000 1592000 1621000 1624000 1529000 186SL08356 19891 1467000 1463000 1489000 1493000 1550000 1545000 186SL08356 19892 1583000 1619000 1639000 1654000 1667000 1632000 186SL08356 19901 1464000 1462000 1506000 1531000 1545000 1535000 186SL08356 19902 1579000 1579000 1598000 1600000 1554000 1491000 186SL08356 19911 1407000 1435000 1522030 1497000 1477000 1483030 186SL08356 19912 1537000 1574000 1567000 1574030 1598060 1573000