186SL0879172018301 205A 19590401 19730126 2857N 01334W 2 00000R 0000 MM 186SL0879272018301 Arrecife-A Spain Inst. Espanol Ocean. 186SL087930001 186SL087930002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL087930003 by the 186SL087930004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL087930005 JOINT ARCHIVE FOR SEA LEVEL 186SL087930006 186SL087930007Station : Arrecife-A Latitude: 28 57.0N 186SL087930008Country : Spain Longitude: 013 34.0W 186SL087930009JASL # : 205A Time Meridian: GMT 186SL087930010GLOSS # : none TOGA #: none NODC #: 72018301 186SL087930011Contributor : Instituto Espanol de Oceanografia 186SL087930012 C/ Corazon de Maria, No. 8 - 1 186SL087930013 28002 Madrid 186SL087930014 SPAIN 186SL087930015Originator : same 186SL087930016Original Data: analog 186SL087930017Instrmnt Type: A.OTT, float and stilling well 186SL087930018Digitzd Intvl: one hour 186SL087930019Present Data : Hourly, daily, and monthly values obtained by: 186SL087930020 Hourly : direct digitization, no filter 186SL087930021 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL087930022 centered on noon applied to the hourly data 186SL087930023 with respective periods of the 95, 50, and 5% 186SL087930024 amplitude points at 124.0, 60.2, and 40.2 hours 186SL087930025 Monthly: Simple average of all daily values; calculated if 186SL087930026 7 or fewer days are missing 186SL087930027Span of data : 01 Apr 1959 - 26 Jan 1973 186SL087930028Gaps > 1 mon : 22 Oct 1959 - 09 Dec 1959;01 Nov 1965 - 30 Nov 1965 186SL087930029Time Refernce: GMT (00-23 hours) Space-filler Flag :-9999 186SL087930030Units : millimeters Missing Data Flag :99999 186SL087930031Refernce Levl: The data have been linked to tide staff zero 186SL087930032 and fixed bench marks by the originators. 186SL087930033Comment : This series is separate from Arrecife-B because 186SL087930034 of a sharp level shift on 27 Jan 1973. The 186SL087930035 daily values agree reasonably well with S.Cruz 186SL087930036 de la Palma except between Jan-Aug 1960 when 186SL087930037 Arrecife-A is low by about 10 cm. However, 186SL087930038 reference level shifts could not be identified 186SL087930039 in the hourly residuals of either series. 186SL087930040 186SL087930041 CI MISSING REPLACED GAPS QUESTIONABLE 186SL087930042YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL087930043---- --- -------------------- --------------- -------------------- 186SL0879300441959 62 295-343 none none 186SL0879300451960 100 none (17)026-(05)027 12-17,88-90,130-132 186SL0879300461961 100 none (07)356-(00)357 none 186SL0879300471962 100 none none 38-39,94-97 186SL0879300481963 97 264-273 none none 186SL0879300491964 96 36-52 (15)269-(23)269 293-296 186SL0879300501965 92 305-334 (11)289-(00)290 16-21,31-34 186SL0879300511966 100 none (02)142-(11)142 none 186SL0879300521967 100 none (00)255-(23)255 none 186SL0879300531968 98 305-313 none none 186SL0879300541969 100 none (05)102-(15)102 208-209,236-240 186SL087930055 (04)141-(14)141 186SL087930056 (13)157-(23)157 186SL0879300571970 100 none (05)064-(22)064 36-37 186SL087930058 (14)127-(00)128 186SL087930059 (15)128-(23)128 186SL087930060 (11)156-(23)156 186SL087930061 (09)187-(19)187 186SL087930062 (07)229-(18)229 186SL087930063 (16)233-(23)233 186SL087930064 (11)238-(20)238 186SL087930065 (03)292-(10)292 186SL087930066 (12)301-(23)301 186SL0879300671971 100 none (11)106-(23)106 21-65,144-146,218- 186SL087930068 (12)121-(23)121 220 186SL087930069 (11)142-(04)143 186SL087930070 (12)349-(23)349 186SL0879300711972 98 113-121 (04)175-(12)175 17-23,122-123,322- 186SL087930072 323 186SL0879300731973 7 none none none 186SL087930074 186SL087930075 QUALITY ASSESSMENT POLICY 186SL087930076 186SL087930077 The quality assessment is mostly based on the residuals 186SL087930078 (observed data minus predicted tides) of the hourly data. This 186SL087930079 assessment also applies to the daily and monthly data since 186SL087930080 they were derived from the quality-controlled hourly data. 186SL087930081 186SL087930082 The following abbreviations are used in the assessment: 186SL087930083 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL087930084 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL087930085 research program; NODC - National Oceanographic Data Center; 186SL087930086 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL087930087 Gaps > 1 mon - missing data in a span greater than one month; 186SL087930088 Refernce - reference. 186SL087930089 186SL087930090 The following corrections are made to the hourly data 186SL087930091 prior to this assessment: 186SL087930092 1) Gaps or obviously wrong data points in a span less than 186SL087930093 25 hours are filled by the predicted tide method*. 186SL087930094 2) Timing errors of exact increments of an hour are corrected 186SL087930095 by shifting the data. 186SL087930096 3) Reference level shifts are only corrected after information 186SL087930097 from tide staff readings or comparative readings with a fixed 186SL087930098 bench mark are checked to verify that the shift was not a 186SL087930099 natural event. If comparative readings are missing or 186SL087930100 incomplete, comparisons of the data with nearby stations 186SL087930101 may warrant the adjustment of some obvious shifts. 186SL087930102 4) Data with unresolved datum shifts are not disseminated. 186SL087930103 However, if sufficient time spans of data are available before 186SL087930104 or after the year(s) with the unresolved shift(s), a subset of 186SL087930105 quality assured data is made available. Thus, the Span field 186SL087930106 in the Quality Assessment may not match the span of the 186SL087930107 distribution data set. As the questionable datum shifts are 186SL087930108 resolved, the data set will be updated. Although this policy 186SL087930109 adds some complexity, it allows more rapid dissemination of 186SL087930110 at least the quality assured years. 186SL087930111 186SL087930112 For each year, the following information is documented from 186SL087930113 the quality-controlled hourly data with dates given as the nth 186SL087930114 day of the year starting from 1 January: 186SL087930115 1) a Completeness Index (CI) based on the percentage of hours 186SL087930116 with available data, 186SL087930117 2) a list of gaps longer than a day, 186SL087930118 3) a summary of days with consecutive missing or obviously 186SL087930119 wrong data in a time span longer than 6 but less than 25 186SL087930120 hours that have been replaced, with hours in parentheses, and 186SL087930121 4) a summary of days with questionable fluctuations in the 186SL087930122 residual series. Fluctuations within the residuals are 186SL087930123 considered significant and are noted if they are greater than 186SL087930124 25 cm. This policy has changed slightly as of October 1992: 186SL087930125 only suspicious fluctuations due to obvious instrumentation 186SL087930126 problems are noted. Minor timing drifts are no longer 186SL087930127 included in the list of questionable days. 186SL087930128 186SL087930129 Note : If the predicted tides poorly model the observed heights 186SL087930130 due to the inability of the tidal analysis to completely resolv 186SL087930131 the non-linear shallow water effects, the residuals are not 186SL087930132 suitable for assessing the data quality. Instead, a subjective 186SL087930133 comment on the quality of the data is provided. 186SL087930134 186SL087930135 *The predicted tides are obtained with the use of a harmonic 186SL087930136 analysis program (Foreman, 1977) which is executed on a year 186SL087930137 of apparently good data for a given station. The Predicted 186SL087930138 Tide Method for filling gaps consists of statistically 186SL087930139 comparing the predicted tides to the observed data and 186SL087930140 shifting the predicted tides in time to correct for timing 186SL087930141 differences. Then the linear interpolation between hourly 186SL087930142 values at the end points of the gap in the residual series is 186SL087930143 added to the corresponding corrected predicted tide data to 186SL087930144 obtain interpolated values over the span of the gap. 186SL087930145 186SL087930146 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL087930147 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL087930148 186SL087930149 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL087930150 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL087930151 Victoria B.C. Pacific Marine Science Report 77-10. 186SL087930152 186SL08796 19591 999999999999999999999999 1403000 1431000 1418000 186SL08796 19592 1458000 1507000 1504000999999999999999999999999 186SL08796 19601 1377000 1417000 1424000 1435000 1451000 1452000 186SL08796 19602 1483000 1496000 1487000 1511000 1494000 1470000 186SL08796 19611 1389000 1372000 1436000 1456000 1498000 1460000 186SL08796 19612 1511000 1514000 1507000 1517000 1514000 1476000 186SL08796 19621 1383000 1304000 1344000 1353000 1351000 1353000 186SL08796 19622 1397000 1501000 1481000 1508000 1486000 1445000 186SL08796 19631 1487000 1437000 1387000 1432000 1412000 1407000 186SL08796 19632 1461000 147800099999999 1454000 1466000 1466000 186SL08796 19641 141400099999999 1423000 1404000 1404000 1464000 186SL08796 19642 1476000 1474000 1467000 1489000 1449000 1415000 186SL08796 19651 1403000 1433000 1381000 1406000 1473000 1495000 186SL08796 19652 1512000 1535000 1505000 152400099999999 1423000 186SL08796 19661 1469000 1464000 1505000 1496000 1530000 1496000 186SL08796 19662 1512000 1554000 1553000 1525000 1496000 1445000 186SL08796 19671 1419000 1452000 1478000 1528000 1517000 1513000 186SL08796 19672 1553000 1607000 1575000 1577000 1590000 1508000 186SL08796 19681 1462000 1473000 1463000 1455000 1490000 1506000 186SL08796 19682 1551000 1589000 1560000 1534010 1591070 1532000 186SL08796 19691 1543000 1548000 1526000 1461000 1478000 1520000 186SL08796 19692 1529000 1577000 1536000 1538000 1555000 1488000 186SL08796 19701 1494000 1478000 1477000 1471000 1474000 1462000 186SL08796 19702 1509000 1536000 1507000 1480000 1459000 1462000 186SL08796 19711 1434000 1453000 1467000 1446000 1438000 1455000 186SL08796 19712 1516000 1546000 1528000 1515000 1498000 1434000 186SL08796 19721 1453000 1435000 142100099999999 1459000 1473000 186SL08796 19722 1485000 1515000 1519000 1525000 1507000 1463000 186SL08796 19731 14240509999999999999999999999999999999999999999 186SL08796 19732 999999999999999999999999999999999999999999999999