186SL0708130149701 064A 19840810 19931231 0929S 14708E 2 00000R 0000 MM 186SL0708230149701 Port Moresby Papua New Guinea CSIRO 186SL070830001 186SL070830002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL070830003 by the 186SL070830004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL070830005 JOINT ARCHIVE FOR SEA LEVEL 186SL070830006 186SL070830007Station : Port Moresby Latitude: 09 28.7S 186SL070830008Country : Papua New Guinea Longitude: 147 08.4E 186SL070830009JASL # : 064A Time Meridian: 150E (GMT + 10 hr) 186SL070830010GLOSS # : none TOGA #: P024 NODC #: 30149701 186SL070830011Contributor : CSIRO 186SL070830012 Division of Oceanography 186SL070830013 GPO Box 1538 186SL070830014 Hobart, Tasmania 7001 186SL070830015Originator : same 186SL070830016Original Data: digital 186SL070830017Instrmnt Type: Leupold Stevens analog-to-digital recorder 186SL070830018Digitzd Intvl: 15 minutes 186SL070830019Present Data : Hourly, daily, and monthly values obtained by: 186SL070830020 Hourly : simple Gaussian filter 186SL070830021 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL070830022 centered on noon applied to the hourly data 186SL070830023 with respective periods of the 95, 50, and 5% 186SL070830024 amplitude points at 124.0, 60.2, and 40.2 hours 186SL070830025 Monthly: Simple average of all daily values; calculated if 186SL070830026 7 or fewer days are missing 186SL070830027Span of data : 10 Aug 1984 - 31 Dec 1993 186SL070830028Gaps > 1 mon : none 186SL070830029Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL070830030Units : millimeters Missing Data Flag :99999 186SL070830031Refernce Levl: All heights have been referred to the station tide 186SL070830032 staff zero which is linked to fixed bench marks 186SL070830033Comment : The daily and monthly means reveal no 186SL070830034 apparent reference level changes or trends. The 186SL070830035 gauge is located within the harbor. 186SL070830036 186SL070830037 CI MISSING REPLACED GAPS QUESTIONABLE 186SL070830038YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL070830039---- --- -------------------- --------------- -------------------- 186SL0708300401984 36 310-311,316-325 none none 186SL0708300411985 99 158-162 none none 186SL0708300421986 99 343-344 none none 186SL0708300431987 98 270-279 (00)281-(23)281 none 186SL0708300441988 96 26-28,144-148, none none 186SL070830045 195-197,359-366 186SL0708300461989 99 1-2,150-151 none 51-58 186SL0708300471990 100 none none none 186SL0708300481991 99 151-154 (14)273-(01)274 none 186SL0708300491992 92 91-121 none none 186SL0708300501993 100 none none none 186SL070830051 186SL070830052 QUALITY ASSESSMENT POLICY 186SL070830053 186SL070830054 The quality assessment is mostly based on the residuals 186SL070830055 (observed data minus predicted tides) of the hourly data. This 186SL070830056 assessment also applies to the daily and monthly data since 186SL070830057 they were derived from the quality-controlled hourly data. 186SL070830058 186SL070830059 The following abbreviations are used in the assessment: 186SL070830060 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL070830061 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL070830062 research program; NODC - National Oceanographic Data Center; 186SL070830063 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL070830064 Gaps > 1 mon - missing data in a span greater than one month; 186SL070830065 Refernce - reference. 186SL070830066 186SL070830067 The following corrections are made to the hourly data 186SL070830068 prior to this assessment: 186SL070830069 1) Gaps or obviously wrong data points in a span less than 186SL070830070 25 hours are filled by the predicted tide method*. 186SL070830071 2) Timing errors of exact increments of an hour are corrected 186SL070830072 by shifting the data. 186SL070830073 3) Reference level shifts are only corrected after information 186SL070830074 from tide staff readings or comparative readings with a fixed 186SL070830075 bench mark are checked to verify that the shift was not a 186SL070830076 natural event. If comparative readings are missing or 186SL070830077 incomplete, comparisons of the data with nearby stations 186SL070830078 may warrant the adjustment of some obvious shifts. 186SL070830079 4) Data with unresolved datum shifts are not disseminated. 186SL070830080 However, if sufficient time spans of data are available before 186SL070830081 or after the year(s) with the unresolved shift(s), a subset of 186SL070830082 quality assured data is made available. Thus, the Span field 186SL070830083 in the Quality Assessment may not match the span of the 186SL070830084 distribution data set. As the questionable datum shifts are 186SL070830085 resolved, the data set will be updated. Although this policy 186SL070830086 adds some complexity, it allows more rapid dissemination of 186SL070830087 at least the quality assured years. 186SL070830088 186SL070830089 For each year, the following information is documented from 186SL070830090 the quality-controlled hourly data with dates given as the nth 186SL070830091 day of the year starting from 1 January: 186SL070830092 1) a Completeness Index (CI) based on the percentage of hours 186SL070830093 with available data, 186SL070830094 2) a list of gaps longer than a day, 186SL070830095 3) a summary of days with consecutive missing or obviously 186SL070830096 wrong data in a time span longer than 6 but less than 25 186SL070830097 hours that have been replaced, with hours in parentheses, and 186SL070830098 4) a summary of days with questionable fluctuations in the 186SL070830099 residual series. Fluctuations within the residuals are 186SL070830100 considered significant and are noted if they are greater than 186SL070830101 25 cm. This policy has changed slightly as of October 1992: 186SL070830102 only suspicious fluctuations due to obvious instrumentation 186SL070830103 problems are noted. Minor timing drifts are no longer 186SL070830104 included in the list of questionable days. 186SL070830105 186SL070830106 Note : If the predicted tides poorly model the observed heights 186SL070830107 due to the inability of the tidal analysis to completely resolv 186SL070830108 the non-linear shallow water effects, the residuals are not 186SL070830109 suitable for assessing the data quality. Instead, a subjective 186SL070830110 comment on the quality of the data is provided. 186SL070830111 186SL070830112 *The predicted tides are obtained with the use of a harmonic 186SL070830113 analysis program (Foreman, 1977) which is executed on a year 186SL070830114 of apparently good data for a given station. The Predicted 186SL070830115 Tide Method for filling gaps consists of statistically 186SL070830116 comparing the predicted tides to the observed data and 186SL070830117 shifting the predicted tides in time to correct for timing 186SL070830118 differences. Then the linear interpolation between hourly 186SL070830119 values at the end points of the gap in the residual series is 186SL070830120 added to the corresponding corrected predicted tide data to 186SL070830121 obtain interpolated values over the span of the gap. 186SL070830122 186SL070830123 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL070830124 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL070830125 186SL070830126 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL070830127 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL070830128 Victoria B.C. Pacific Marine Science Report 77-10. 186SL070830129 186SL07086 19841 999999999999999999999999999999999999999999999999 186SL07086 19842 9999999999999999 1713000 175000099999999 1831000 186SL07086 19851 1788000 1862000 1842000 1843000 1895000 1846050 186SL07086 19852 1801000 1756000 1785000 1768000 1790000 1769000 186SL07086 19861 1870000 1844000 1896000 1909000 1807000 1829000 186SL07086 19862 1770000 1781000 1775000 1758000 1808000 1773020 186SL07086 19871 1795000 1842000 1835000 1882000 1825000 1838000 186SL07086 19872 1782000 1760000 1749040 1715060 1770000 1828000 186SL07086 19881 1840030 1880000 1924000 1820000 1817040 1816000 186SL07086 19882 1826030 1842000 1827000 1845000 187300099999999 186SL07086 19891 1822020 1827000 1850000 1848000 1847020 1811000 186SL07086 19892 1815000 1802000 1791000 1834000 1878000 1895000 186SL07086 19901 1937000 1828000 1894000 1833000 1909000 1925000 186SL07086 19902 1858000 1801000 1867000 1832000 1853000 1870000 186SL07086 19911 1845000 1879000 1961000 1876000 1829010 1709030 186SL07086 19912 1759000 1800000 1737000 1802000 1820000 1797010 186SL07086 19921 1833000 1810000 185701099999999 1852000 1832000 186SL07086 19922 1813000 1771000 1753000 1760000 1769000 1799000 186SL07086 19931 1825000 1857000 1815000 1817000 1819000 1774000 186SL07086 19932 1783000 1727000 1712000 1733000 1734000 1810000