186SL0774110104001 143A 19841212 19931231 0414N 10037E 2 00000R 0000 MM 186SL0774210104001 Lumut Malaysia Dept. of Survey and Mapping 186SL077430001 186SL077430002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL077430003 by the 186SL077430004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL077430005 JOINT ARCHIVE FOR SEA LEVEL 186SL077430006 186SL077430007Station : Lumut Latitude: 04 14.4N 186SL077430008Country : Malaysia Longitude: 100 36.8E 186SL077430009JASL # : 143A Time Meridian: 120E (GMT + 8 hr) 186SL077430010GLOSS # : 043 TOGA #: I034 NODC #: 10104001 186SL077430011Contributor : Dept. of Survey and Mapping 186SL077430012 Jalan Gurney 186SL077430013 50578 Kuala Lumpur, Malaysia 186SL077430014Originator : same 186SL077430015Original Data: digital; samples taken every 10 sec; 50 sec average 186SL077430016Instrmnt Type: Magnetic Tape Type Tide Gauge, Model LLT- 186SL077430017 3AD (Kyowa Shoko Co. LTD, Japan) 186SL077430018Digitzd Intvl: one hour 186SL077430019Present Data : Hourly, daily, and monthly values obtained by: 186SL077430020 Hourly : Five-point least squares approximation (more 186SL077430021 information available from the address above) 186SL077430022 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL077430023 centered on noon applied to the hourly data 186SL077430024 with respective periods of the 95, 50, and 5% 186SL077430025 amplitude points at 124.0, 60.2, and 40.2 hours 186SL077430026 Monthly: Simple average of all daily values; calculated if 186SL077430027 7 or fewer days are missing 186SL077430028Span of data : 12 Dec 1984 - 31 Dec 1993 186SL077430029Gaps > 1 mon : none 186SL077430030Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL077430031Units : millimeters Missing Data Flag :99999 186SL077430032Refernce Levl: The sea level heights are referred to the zero 186SL077430033 point assigned to the tide gauge. Bench mark 186SL077430034 information is available upon request from the 186SL077430035 contributors. 186SL077430036Comment : The daily and monthly means of Lumut and an 186SL077430037 adjacent station, Langkawi, agree very well. 186SL077430038 186SL077430039 CI MISSING REPLACED GAPS QUESTIONABLE 186SL077430040YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL077430041---- --- -------------------- --------------- -------------------- 186SL0774300421984 5 none none none 186SL0774300431985 87 93-94,147-176, none 30-32,62,220-221 186SL077430044 247-252,309-317 186SL0774300451986 100 none none 127 186SL0774300461987 96 69-73,250-261 none none 186SL0774300471988 100 none none 142,186-187,248-249, 186SL077430048 270-271,323-325 186SL0774300491989 100 none none none 186SL0774300501990 100 none none none 186SL0774300511991 100 none none none 186SL0774300521992 100 none none none 186SL0774300531993 90 12-20,156-187 none none 186SL077430054 186SL077430055 QUALITY ASSESSMENT POLICY 186SL077430056 186SL077430057 The quality assessment is mostly based on the residuals 186SL077430058 (observed data minus predicted tides) of the hourly data. This 186SL077430059 assessment also applies to the daily and monthly data since 186SL077430060 they were derived from the quality-controlled hourly data. 186SL077430061 186SL077430062 The following abbreviations are used in the assessment: 186SL077430063 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL077430064 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL077430065 research program; NODC - National Oceanographic Data Center; 186SL077430066 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL077430067 Gaps > 1 mon - missing data in a span greater than one month; 186SL077430068 Refernce - reference. 186SL077430069 186SL077430070 The following corrections are made to the hourly data 186SL077430071 prior to this assessment: 186SL077430072 1) Gaps or obviously wrong data points in a span less than 186SL077430073 25 hours are filled by the predicted tide method*. 186SL077430074 2) Timing errors of exact increments of an hour are corrected 186SL077430075 by shifting the data. 186SL077430076 3) Reference level shifts are only corrected after information 186SL077430077 from tide staff readings or comparative readings with a fixed 186SL077430078 bench mark are checked to verify that the shift was not a 186SL077430079 natural event. If comparative readings are missing or 186SL077430080 incomplete, comparisons of the data with nearby stations 186SL077430081 may warrant the adjustment of some obvious shifts. 186SL077430082 4) Data with unresolved datum shifts are not disseminated. 186SL077430083 However, if sufficient time spans of data are available before 186SL077430084 or after the year(s) with the unresolved shift(s), a subset of 186SL077430085 quality assured data is made available. Thus, the Span field 186SL077430086 in the Quality Assessment may not match the span of the 186SL077430087 distribution data set. As the questionable datum shifts are 186SL077430088 resolved, the data set will be updated. Although this policy 186SL077430089 adds some complexity, it allows more rapid dissemination of 186SL077430090 at least the quality assured years. 186SL077430091 186SL077430092 For each year, the following information is documented from 186SL077430093 the quality-controlled hourly data with dates given as the nth 186SL077430094 day of the year starting from 1 January: 186SL077430095 1) a Completeness Index (CI) based on the percentage of hours 186SL077430096 with available data, 186SL077430097 2) a list of gaps longer than a day, 186SL077430098 3) a summary of days with consecutive missing or obviously 186SL077430099 wrong data in a time span longer than 6 but less than 25 186SL077430100 hours that have been replaced, with hours in parentheses, and 186SL077430101 4) a summary of days with questionable fluctuations in the 186SL077430102 residual series. Fluctuations within the residuals are 186SL077430103 considered significant and are noted if they are greater than 186SL077430104 25 cm. This policy has changed slightly as of October 1992: 186SL077430105 only suspicious fluctuations due to obvious instrumentation 186SL077430106 problems are noted. Minor timing drifts are no longer 186SL077430107 included in the list of questionable days. 186SL077430108 186SL077430109 Note : If the predicted tides poorly model the observed heights 186SL077430110 due to the inability of the tidal analysis to completely resolv 186SL077430111 the non-linear shallow water effects, the residuals are not 186SL077430112 suitable for assessing the data quality. Instead, a subjective 186SL077430113 comment on the quality of the data is provided. 186SL077430114 186SL077430115 *The predicted tides are obtained with the use of a harmonic 186SL077430116 analysis program (Foreman, 1977) which is executed on a year 186SL077430117 of apparently good data for a given station. The Predicted 186SL077430118 Tide Method for filling gaps consists of statistically 186SL077430119 comparing the predicted tides to the observed data and 186SL077430120 shifting the predicted tides in time to correct for timing 186SL077430121 differences. Then the linear interpolation between hourly 186SL077430122 values at the end points of the gap in the residual series is 186SL077430123 added to the corresponding corrected predicted tide data to 186SL077430124 obtain interpolated values over the span of the gap. 186SL077430125 186SL077430126 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL077430127 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL077430128 186SL077430129 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL077430130 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL077430131 Victoria B.C. Pacific Marine Science Report 77-10. 186SL077430132 186SL07746 19841 999999999999999999999999999999999999999999999999 186SL07746 19842 999999999999999999999999999999999999999999999999 186SL07746 19851 2084000 2109000 2119000 2161020 222905099999999 186SL07746 19852 2256000 2196000 2189070 228100099999999 2179000 186SL07746 19861 2078000 2016000 2046000 2156000 2248000 2210000 186SL07746 19862 2252000 2263000 2180000 2213000 2255000 2040000 186SL07746 19871 1986000 2006000 1973050 2030000 2164000 2224000 186SL07746 19872 2255000 216200099999999 2169000 2346000 2279000 186SL07746 19881 2141000 2119000 2099000 2179000 2304000 2284000 186SL07746 19882 2183000 2191000 2180000 2319000 2363000 2227000 186SL07746 19891 2132000 2076000 2111000 2181000 2318000 2305000 186SL07746 19892 2278000 2222000 2185000 2229000 2283000 2094000 186SL07746 19901 2049000 1981000 1998000 2184000 2255000 2298000 186SL07746 19902 2177000 2279000 2201000 2216000 2257000 2143000 186SL07746 19911 2055000 2063000 2049000 2168000 2190000 2250000 186SL07746 19912 2175000 2153000 2197000 2228000 2233000 2138000 186SL07746 19921 2034000 1984000 2026000 2109000 2260000 2319000 186SL07746 19922 2242000 2258000 2229000 2340000 2244000 2192000 186SL07746 19931 99999999 2017000 2048000 2163000 220900099999999 186SL07746 19932 2247060 2270000 2194000 2254000 2283000 2265000