186SL0857112112301 338A 19780101 19850531 2210N 11333E 2 00000R 0000 MM 186SL0857212112301 Macau Portugal Inst. Hidro. Marinha 186SL085730001 186SL085730002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL085730003 by the 186SL085730004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL085730005 JOINT ARCHIVE FOR SEA LEVEL 186SL085730006 186SL085730007Station : Macau Latitude: 22 10.0N 186SL085730008Country : Portugal Longitude: 113 33.0E 186SL085730009JASL # : 338A Time Meridian: 120E (GMT + 8 hr) 186SL085730010GLOSS # : none TOGA #: none NODC #: 12112301 186SL085730011Contributor : Instituto Hidrografico de Marinha 186SL085730012 Rua das Trinas, 49 186SL085730013 P-1296 186SL085730014 Lisboa Codex 186SL085730015 PORTUGAL 186SL085730016Originator : same 186SL085730017Original Data: analog 186SL085730018Instrmnt Type: A.OTT R20T, float and stilling well 186SL085730019Digitzd Intvl: one hour 186SL085730020Present Data : Hourly, daily, and monthly values obtained by: 186SL085730021 Hourly : direct digitization, no filter 186SL085730022 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL085730023 centered on noon applied to the hourly data 186SL085730024 with respective periods of the 95, 50, and 5% 186SL085730025 amplitude points at 124.0, 60.2, and 40.2 hours 186SL085730026 Monthly: Simple average of all daily values; calculated if 186SL085730027 7 or fewer days are missing 186SL085730028Span of data : 01 Jan 1978 - 31 May 1985 186SL085730029Gaps > 1 mon : 31 Dec 1982 - 12 May 1984 186SL085730030Time Refernce: GMT (00-23 hours) Space-filler Flag :-9999 186SL085730031Units : millimeters Missing Data Flag :99999 186SL085730032Refernce Levl: The data have been corrected to tide staff zero 186SL085730033 or fixed bench marks by the originators. This 186SL085730034 series consists of two separate gauges at nearby 186SL085730035 sites 1) Exterior (1978-1982) and 2) Interior 186SL085730036 (1984-1985), both of which have been tied to the 186SL085730037 same fixed benchmarks and datum. 186SL085730038Comment : The residuals (observed minus predicted data) 186SL085730039 contain a high degree of noise with periods of 3 186SL085730040 to 8 hours. This may be due to the insufficient 186SL085730041 approximation of the observed data by the tidal 186SL085730042 analysis. The residuals contain fluctuations 186SL085730043 of up to 75 cm with periods of 1 to 3 186SL085730044 days associated with meteorological events. 186SL085730045 Otherwise, the daily and monthly means 186SL085730046 do not reveal any reference level shifts or 186SL085730047 obvious problems and agree with Hong Kong data. 186SL085730048 186SL085730049 CI MISSING REPLACED GAPS QUESTIONABLE 186SL085730050YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL085730051---- --- -------------------- --------------- -------------------- 186SL0857300521978 100 none (15)113-(01)114 55-57,94-96,121,128- 186SL085730053 130,255-256,286-290, 186SL085730054 318-319,349,361 186SL0857300551979 100 none none 30-31,72-73,92-93, 186SL085730056 119,260-264,322-323 186SL0857300571980 100 none none 8,17-18,59-60,104- 186SL085730058 105,154-155,184-188 186SL0857300591981 99 154-157 (14)321-(04)322 62,227,229 186SL0857300601982 91 273-276,297-314, none 13,40-41,340 186SL085730061 349-351,353-363, 186SL085730062 365 186SL0857300631983 0 1-365 none none 186SL0857300641984 61 152-154,181-185, none none 186SL085730065 206-208,233-235 186SL0857300661985 41 129-131 none none 186SL085730067 186SL085730068 QUALITY ASSESSMENT POLICY 186SL085730069 186SL085730070 The quality assessment is mostly based on the residuals 186SL085730071 (observed data minus predicted tides) of the hourly data. This 186SL085730072 assessment also applies to the daily and monthly data since 186SL085730073 they were derived from the quality-controlled hourly data. 186SL085730074 186SL085730075 The following abbreviations are used in the assessment: 186SL085730076 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL085730077 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL085730078 research program; NODC - National Oceanographic Data Center; 186SL085730079 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL085730080 Gaps > 1 mon - missing data in a span greater than one month; 186SL085730081 Refernce - reference. 186SL085730082 186SL085730083 The following corrections are made to the hourly data 186SL085730084 prior to this assessment: 186SL085730085 1) Gaps or obviously wrong data points in a span less than 186SL085730086 25 hours are filled by the predicted tide method*. 186SL085730087 2) Timing errors of exact increments of an hour are corrected 186SL085730088 by shifting the data. 186SL085730089 3) Reference level shifts are only corrected after information 186SL085730090 from tide staff readings or comparative readings with a fixed 186SL085730091 bench mark are checked to verify that the shift was not a 186SL085730092 natural event. If comparative readings are missing or 186SL085730093 incomplete, comparisons of the data with nearby stations 186SL085730094 may warrant the adjustment of some obvious shifts. 186SL085730095 4) Data with unresolved datum shifts are not disseminated. 186SL085730096 However, if sufficient time spans of data are available before 186SL085730097 or after the year(s) with the unresolved shift(s), a subset of 186SL085730098 quality assured data is made available. Thus, the Span field 186SL085730099 in the Quality Assessment may not match the span of the 186SL085730100 distribution data set. As the questionable datum shifts are 186SL085730101 resolved, the data set will be updated. Although this policy 186SL085730102 adds some complexity, it allows more rapid dissemination of 186SL085730103 at least the quality assured years. 186SL085730104 186SL085730105 For each year, the following information is documented from 186SL085730106 the quality-controlled hourly data with dates given as the nth 186SL085730107 day of the year starting from 1 January: 186SL085730108 1) a Completeness Index (CI) based on the percentage of hours 186SL085730109 with available data, 186SL085730110 2) a list of gaps longer than a day, 186SL085730111 3) a summary of days with consecutive missing or obviously 186SL085730112 wrong data in a time span longer than 6 but less than 25 186SL085730113 hours that have been replaced, with hours in parentheses, and 186SL085730114 4) a summary of days with questionable fluctuations in the 186SL085730115 residual series. Fluctuations within the residuals are 186SL085730116 considered significant and are noted if they are greater than 186SL085730117 25 cm. This policy has changed slightly as of October 1992: 186SL085730118 only suspicious fluctuations due to obvious instrumentation 186SL085730119 problems are noted. Minor timing drifts are no longer 186SL085730120 included in the list of questionable days. 186SL085730121 186SL085730122 Note : If the predicted tides poorly model the observed heights 186SL085730123 due to the inability of the tidal analysis to completely resolv 186SL085730124 the non-linear shallow water effects, the residuals are not 186SL085730125 suitable for assessing the data quality. Instead, a subjective 186SL085730126 comment on the quality of the data is provided. 186SL085730127 186SL085730128 *The predicted tides are obtained with the use of a harmonic 186SL085730129 analysis program (Foreman, 1977) which is executed on a year 186SL085730130 of apparently good data for a given station. The Predicted 186SL085730131 Tide Method for filling gaps consists of statistically 186SL085730132 comparing the predicted tides to the observed data and 186SL085730133 shifting the predicted tides in time to correct for timing 186SL085730134 differences. Then the linear interpolation between hourly 186SL085730135 values at the end points of the gap in the residual series is 186SL085730136 added to the corresponding corrected predicted tide data to 186SL085730137 obtain interpolated values over the span of the gap. 186SL085730138 186SL085730139 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL085730140 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL085730141 186SL085730142 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL085730143 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL085730144 Victoria B.C. Pacific Marine Science Report 77-10. 186SL085730145 186SL08576 19781 1723000 1712000 1772000 1736000 1851000 1789000 186SL08576 19782 1776000 1873000 1994000 2167000 1904000 1830000 186SL08576 19791 1651000 1687000 1782000 1778000 1873000 1831000 186SL08576 19792 1811000 1821000 1947000 2059000 1935000 1737000 186SL08576 19801 1690000 1727000 1758000 1771000 1876000 1757000 186SL08576 19802 1748000 1797000 2028000 2001000 1938000 1862000 186SL08576 19811 1849000 1794000 1689000 1783000 1743000 1824040 186SL08576 19812 1831000 1784000 1847000 2003000 1970000 1803000 186SL08576 19821 1722000 1743000 1741000 1791000 1779000 1857000 186SL08576 19822 1775000 1680000 1992010999999999999999999999999 186SL08576 19831 999999999999999999999999999999999999999999999999 186SL08576 19832 999999999999999999999999999999999999999999999999 186SL08576 19841 9999999999999999999999999999999999999999 1807040 186SL08576 19842 1691060 1876030 1804000 2001000 1923000 1774000 186SL08576 19851 1660000 1761000 1793000 1691000 171704099999999 186SL08576 19852 999999999999999999999999999999999999999999999999