186SL0855110106201 326A 19861216 19911231 0614N 10206E 2 00000R 0000 MM 186SL0855210106201 Geting Malaysia Dept. of Survey and Mapping 186SL085530001 186SL085530002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL085530003 by the 186SL085530004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL085530005 JOINT ARCHIVE FOR SEA LEVEL 186SL085530006 186SL085530007Station : Geting Latitude: 06 13.6N 186SL085530008Country : Malaysia Longitude: 102 06.4E 186SL085530009JASL # : 326A Time Meridian: 120E (GMT + 8 hr) 186SL085530010GLOSS # : none TOGA #: none NODC #: 10106201 186SL085530011Contributor : Dept. of Survey and Mapping 186SL085530012 Jalan Gurney 186SL085530013 50578 Kuala Lumpur, Malaysia 186SL085530014Originator : same 186SL085530015Original Data: digital; samples taken every 10 sec; 50 sec average 186SL085530016Instrmnt Type: Magnetic Tape Type Tide Gauge, Model LLT- 186SL085530017 3AD (Kyowa Shoko Co. LTD, Japan) 186SL085530018Digitzd Intvl: one hour 186SL085530019Present Data : Hourly, daily, and monthly values obtained by: 186SL085530020 Hourly : Five-point least squares approximation (more 186SL085530021 information available from the address above) 186SL085530022 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL085530023 centered on noon applied to the hourly data 186SL085530024 with respective periods of the 95, 50, and 5% 186SL085530025 amplitude points at 124.0, 60.2, and 40.2 hours 186SL085530026 Monthly: Simple average of all daily values; calculated if 186SL085530027 7 or fewer days are missing 186SL085530028Span of data : 16 Dec 1986 - 31 Dec 1991 186SL085530029Gaps > 1 mon : none 186SL085530030Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL085530031Units : millimeters Missing Data Flag :99999 186SL085530032Refernce Levl: The sea level heights are referred to the zero 186SL085530033 point assigned to the tide gauge. Bench mark 186SL085530034 information is available upon request from the 186SL085530035 contributors. 186SL085530036Comment : The daily and monthly means do not reveal any 186SL085530037 obvious reference level shifts or trends and 186SL085530038 agree with Cendering, although the tidal enery 186SL085530039 is about half as strong and the annual cycle is 186SL085530040 slightly stronger at Geting. 186SL085530041 186SL085530042 CI MISSING REPLACED GAPS QUESTIONABLE 186SL085530043YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL085530044---- --- -------------------- --------------- -------------------- 186SL0855300451986 4 none none none 186SL0855300461987 100 none none 45-48,158 186SL0855300471988 100 none none 325-329 186SL0855300481989 97 180-191 none 210-211 186SL0855300491990 100 none none 144-146,336-338, 186SL085530050 347-354 186SL0855300511991 100 none none 323-328 186SL085530052 186SL085530053 QUALITY ASSESSMENT POLICY 186SL085530054 186SL085530055 The quality assessment is mostly based on the residuals 186SL085530056 (observed data minus predicted tides) of the hourly data. This 186SL085530057 assessment also applies to the daily and monthly data since 186SL085530058 they were derived from the quality-controlled hourly data. 186SL085530059 186SL085530060 The following abbreviations are used in the assessment: 186SL085530061 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL085530062 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL085530063 research program; NODC - National Oceanographic Data Center; 186SL085530064 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL085530065 Gaps > 1 mon - missing data in a span greater than one month; 186SL085530066 Refernce - reference. 186SL085530067 186SL085530068 The following corrections are made to the hourly data 186SL085530069 prior to this assessment: 186SL085530070 1) Gaps or obviously wrong data points in a span less than 186SL085530071 25 hours are filled by the predicted tide method*. 186SL085530072 2) Timing errors of exact increments of an hour are corrected 186SL085530073 by shifting the data. 186SL085530074 3) Reference level shifts are only corrected after information 186SL085530075 from tide staff readings or comparative readings with a fixed 186SL085530076 bench mark are checked to verify that the shift was not a 186SL085530077 natural event. If comparative readings are missing or 186SL085530078 incomplete, comparisons of the data with nearby stations 186SL085530079 may warrant the adjustment of some obvious shifts. 186SL085530080 4) Data with unresolved datum shifts are not disseminated. 186SL085530081 However, if sufficient time spans of data are available before 186SL085530082 or after the year(s) with the unresolved shift(s), a subset of 186SL085530083 quality assured data is made available. Thus, the Span field 186SL085530084 in the Quality Assessment may not match the span of the 186SL085530085 distribution data set. As the questionable datum shifts are 186SL085530086 resolved, the data set will be updated. Although this policy 186SL085530087 adds some complexity, it allows more rapid dissemination of 186SL085530088 at least the quality assured years. 186SL085530089 186SL085530090 For each year, the following information is documented from 186SL085530091 the quality-controlled hourly data with dates given as the nth 186SL085530092 day of the year starting from 1 January: 186SL085530093 1) a Completeness Index (CI) based on the percentage of hours 186SL085530094 with available data, 186SL085530095 2) a list of gaps longer than a day, 186SL085530096 3) a summary of days with consecutive missing or obviously 186SL085530097 wrong data in a time span longer than 6 but less than 25 186SL085530098 hours that have been replaced, with hours in parentheses, and 186SL085530099 4) a summary of days with questionable fluctuations in the 186SL085530100 residual series. Fluctuations within the residuals are 186SL085530101 considered significant and are noted if they are greater than 186SL085530102 25 cm. This policy has changed slightly as of October 1992: 186SL085530103 only suspicious fluctuations due to obvious instrumentation 186SL085530104 problems are noted. Minor timing drifts are no longer 186SL085530105 included in the list of questionable days. 186SL085530106 186SL085530107 Note : If the predicted tides poorly model the observed heights 186SL085530108 due to the inability of the tidal analysis to completely resolv 186SL085530109 the non-linear shallow water effects, the residuals are not 186SL085530110 suitable for assessing the data quality. Instead, a subjective 186SL085530111 comment on the quality of the data is provided. 186SL085530112 186SL085530113 *The predicted tides are obtained with the use of a harmonic 186SL085530114 analysis program (Foreman, 1977) which is executed on a year 186SL085530115 of apparently good data for a given station. The Predicted 186SL085530116 Tide Method for filling gaps consists of statistically 186SL085530117 comparing the predicted tides to the observed data and 186SL085530118 shifting the predicted tides in time to correct for timing 186SL085530119 differences. Then the linear interpolation between hourly 186SL085530120 values at the end points of the gap in the residual series is 186SL085530121 added to the corresponding corrected predicted tide data to 186SL085530122 obtain interpolated values over the span of the gap. 186SL085530123 186SL085530124 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL085530125 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL085530126 186SL085530127 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL085530128 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL085530129 Victoria B.C. Pacific Marine Science Report 77-10. 186SL085530130 186SL08556 19861 999999999999999999999999999999999999999999999999 186SL08556 19862 999999999999999999999999999999999999999999999999 186SL08556 19871 2474000 2337000 2250000 2224000 2135000 2079000 186SL08556 19872 2038000 2087000 2117000 2273000 2333000 2676000 186SL08556 19881 2426000 2391000 2355000 2299000 2130000 2067000 186SL08556 19882 2122000 2165000 2190000 2274000 2713000 2531000 186SL08556 19891 2513000 2385000 2341000 2163000 2147000 2050020 186SL08556 19892 99999999 2095000 2170000 2374000 2527000 2475000 186SL08556 19901 2482000 2394000 2318000 2242000 2189000 2056000 186SL08556 19902 2029000 2057000 2117000 2298000 2416000 2600000 186SL08556 19911 2457000 2398000 2271000 2258000 2174000 2081000 186SL08556 19912 2048000 2081000 2170000 2340000 2648000 2563000