186SL0746111124001 370A 19840101 19900630 1435N 12058E 2 00000R 0000 MM 186SL0746211124001 Manila Philippines Ocean. Surveys Division 186SL074630001 186SL074630002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL074630003 by the 186SL074630004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL074630005 JOINT ARCHIVE FOR SEA LEVEL 186SL074630006 186SL074630007Station : Manila Latitude: 14 35.0N 186SL074630008Country : Philippines Longitude: 120 58.0E 186SL074630009JASL # : 370A Time Meridian: 120E (GMT + 8 hr) 186SL074630010GLOSS # : 073 TOGA #: P011 NODC #: 11124001 186SL074630011Contributor : Oceanographic Surveys Division 186SL074630012 NAMRIA, Binondo Branch 186SL074630013 P. O. Box 1620 186SL074630014 Manila, Philippines 186SL074630015Originator : same 186SL074630016Original Data: analog 186SL074630017Instrmnt Type: A.OTT, gravity type 186SL074630018Digitzd Intvl: one hour 186SL074630019Present Data : Hourly, daily, and monthly values obtained by: 186SL074630020 Hourly : The original digitizing interval was hourly 186SL074630021 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL074630022 centered on noon applied to the hourly data 186SL074630023 with respective periods of the 95, 50, and 5% 186SL074630024 amplitude points at 124.0, 60.2, and 40.2 hours 186SL074630025 Monthly: Simple average of all daily values; calculated if 186SL074630026 7 or fewer days are missing 186SL074630027Span of data : 01 Jan 1984 - 30 Jun 1990 186SL074630028Gaps > 1 mon : none 186SL074630029Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL074630030Units : millimeters Missing Data Flag :99999 186SL074630031Refernce Levl: All data are referred to a historic fixed 186SL074630032 bench mark (1901) 186SL074630033Comment : A timing offset of 15 minutes exists from 16Z 186SL074630034 30 Jun - 15Z 31 Jul 1985. The daily or monthly 186SL074630035 means do not reveal any obvious reference level 186SL074630036 shifts. Significant meteorological events are 186SL074630037 186SL074630038 period (dd/mm/yyyy) event 186SL074630039 ------------------- --------------- 186SL074630040 30/08 - 04/09/1984 typhoon 186SL074630041 23/10 - 30/10/1984 tropical storm 186SL074630042 02/11 - 06/11/1984 typhoon 186SL074630043 04/07 - 06/07/1985 tropical depression 186SL074630044 05/10 - 08/10/1986 tropical storm 186SL074630045 10/10 - 15/10/1986 typhoon 186SL074630046 17/10 - 20/10/1986 tropical storm 186SL074630047 06/11 - 14/11/1986 tropical storm 186SL074630048 186SL074630049 CI MISSING REPLACED GAPS QUESTIONABLE 186SL074630050YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL074630051---- --- -------------------- --------------- -------------------- 186SL0746300521984 100 none none 276-278,288-289,291- 186SL074630053 292,315-316,323 186SL0746300541985 100 none none 5-6,8-10,18-20,33, 186SL074630055 37,39-40,42-43,47- 186SL074630056 48,53-54,102,123- 186SL074630057 124,181-212,263,295- 186SL074630058 296,344,348,365 186SL0746300591986 100 none none 11,56,119,190,248- 186SL074630060 249,280-281 186SL0746300611987 100 none (09)154-(23)154 4-5,31,168,170,183- 186SL074630062 185,219-221,243,270, 186SL074630063 300-301,330 186SL0746300641988 97 270-279,288-291 none 298-299 186SL0746300651989 93 170-174,196-199, none none 186SL074630066 207-210,247-258, 186SL074630067 283-285,325-327 186SL0746300681990 50 none none 172-175,179-180 186SL074630069 186SL074630070 QUALITY ASSESSMENT POLICY 186SL074630071 186SL074630072 The quality assessment is mostly based on the residuals 186SL074630073 (observed data minus predicted tides) of the hourly data. This 186SL074630074 assessment also applies to the daily and monthly data since 186SL074630075 they were derived from the quality-controlled hourly data. 186SL074630076 186SL074630077 The following abbreviations are used in the assessment: 186SL074630078 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL074630079 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL074630080 research program; NODC - National Oceanographic Data Center; 186SL074630081 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL074630082 Gaps > 1 mon - missing data in a span greater than one month; 186SL074630083 Refernce - reference. 186SL074630084 186SL074630085 The following corrections are made to the hourly data 186SL074630086 prior to this assessment: 186SL074630087 1) Gaps or obviously wrong data points in a span less than 186SL074630088 25 hours are filled by the predicted tide method*. 186SL074630089 2) Timing errors of exact increments of an hour are corrected 186SL074630090 by shifting the data. 186SL074630091 3) Reference level shifts are only corrected after information 186SL074630092 from tide staff readings or comparative readings with a fixed 186SL074630093 bench mark are checked to verify that the shift was not a 186SL074630094 natural event. If comparative readings are missing or 186SL074630095 incomplete, comparisons of the data with nearby stations 186SL074630096 may warrant the adjustment of some obvious shifts. 186SL074630097 4) Data with unresolved datum shifts are not disseminated. 186SL074630098 However, if sufficient time spans of data are available before 186SL074630099 or after the year(s) with the unresolved shift(s), a subset of 186SL074630100 quality assured data is made available. Thus, the Span field 186SL074630101 in the Quality Assessment may not match the span of the 186SL074630102 distribution data set. As the questionable datum shifts are 186SL074630103 resolved, the data set will be updated. Although this policy 186SL074630104 adds some complexity, it allows more rapid dissemination of 186SL074630105 at least the quality assured years. 186SL074630106 186SL074630107 For each year, the following information is documented from 186SL074630108 the quality-controlled hourly data with dates given as the nth 186SL074630109 day of the year starting from 1 January: 186SL074630110 1) a Completeness Index (CI) based on the percentage of hours 186SL074630111 with available data, 186SL074630112 2) a list of gaps longer than a day, 186SL074630113 3) a summary of days with consecutive missing or obviously 186SL074630114 wrong data in a time span longer than 6 but less than 25 186SL074630115 hours that have been replaced, with hours in parentheses, and 186SL074630116 4) a summary of days with questionable fluctuations in the 186SL074630117 residual series. Fluctuations within the residuals are 186SL074630118 considered significant and are noted if they are greater than 186SL074630119 25 cm. This policy has changed slightly as of October 1992: 186SL074630120 only suspicious fluctuations due to obvious instrumentation 186SL074630121 problems are noted. Minor timing drifts are no longer 186SL074630122 included in the list of questionable days. 186SL074630123 186SL074630124 Note : If the predicted tides poorly model the observed heights 186SL074630125 due to the inability of the tidal analysis to completely resolv 186SL074630126 the non-linear shallow water effects, the residuals are not 186SL074630127 suitable for assessing the data quality. Instead, a subjective 186SL074630128 comment on the quality of the data is provided. 186SL074630129 186SL074630130 *The predicted tides are obtained with the use of a harmonic 186SL074630131 analysis program (Foreman, 1977) which is executed on a year 186SL074630132 of apparently good data for a given station. The Predicted 186SL074630133 Tide Method for filling gaps consists of statistically 186SL074630134 comparing the predicted tides to the observed data and 186SL074630135 shifting the predicted tides in time to correct for timing 186SL074630136 differences. Then the linear interpolation between hourly 186SL074630137 values at the end points of the gap in the residual series is 186SL074630138 added to the corresponding corrected predicted tide data to 186SL074630139 obtain interpolated values over the span of the gap. 186SL074630140 186SL074630141 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL074630142 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL074630143 186SL074630144 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL074630145 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL074630146 Victoria B.C. Pacific Marine Science Report 77-10. 186SL074630147 186SL07466 19841 2472000 2482000 2523000 2612000 2686000 2731000 186SL07466 19842 2754000 2933000 2737000 2754000 2646000 2564000 186SL07466 19851 2472000 2526000 2463000 2557000 2630000 2784000 186SL07466 19852 2662000 2809000 2758000 2712000 2590000 2525000 186SL07466 19861 2455000 2456000 2507000 2552000 2632000 2652000 186SL07466 19862 2691000 2800000 2746000 2644000 2624000 2485000 186SL07466 19871 2437000 2400000 2442000 2512000 2545000 2653000 186SL07466 19872 2658000 2672000 2678000 2669000 2645000 2551000 186SL07466 19881 2507000 2530000 2568000 2598000 2650030 2709000 186SL07466 19882 2712000 2717000 274305099999999 2661000 2562000 186SL07466 19891 2537000 2532000 2600000 2678000 2673000 2717050 186SL07466 19892 99999999 281300099999999 2741030 2642020 2544000 186SL07466 19901 2515000 2467000 2473000 2556000 2616000 2696010 186SL07466 19902 999999999999999999999999999999999999999999999999