186SL0749110126101 373A 19840101 19900630 0604N 12100E 2 00000R 0000 MM 186SL0749210126101 Jolo Philippines Ocean. Surveys Division 186SL074930001 186SL074930002 QUALITY ASSESSMENT OF SEA LEVEL DATA 186SL074930003 by the 186SL074930004 TOGA SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER 186SL074930005 JOINT ARCHIVE FOR SEA LEVEL 186SL074930006 186SL074930007Station : Jolo Latitude: 06 04.0N 186SL074930008Country : Philippines Longitude: 121 00.0E 186SL074930009JASL # : 373A Time Meridian: 120E (GMT + 8 hr) 186SL074930010GLOSS # : 070 TOGA #: P008 NODC #: 10126101 186SL074930011Contributor : Oceanographic Surveys Division 186SL074930012 NAMRIA, Binondo Branch 186SL074930013 P. O. Box 1620 186SL074930014 Manila, Philippines 186SL074930015Originator : same 186SL074930016Original Data: analog 186SL074930017Instrmnt Type: A.OTT, gravity type 186SL074930018Digitzd Intvl: one hour 186SL074930019Present Data : Hourly, daily, and monthly values obtained by: 186SL074930020 Hourly : The original digitizing interval was hourly 186SL074930021 Daily : 119-point convolution filter (Bloomfield, 1976) 186SL074930022 centered on noon applied to the hourly data 186SL074930023 with respective periods of the 95, 50, and 5% 186SL074930024 amplitude points at 124.0, 60.2, and 40.2 hours 186SL074930025 Monthly: Simple average of all daily values; calculated if 186SL074930026 7 or fewer days are missing 186SL074930027Span of data : 01 Jan 1984 - 30 Jun 1990 186SL074930028Gaps > 1 mon : 31 Mar 1984 - 01 Apr 1984;07 Apr 1985 - 31 Jul 1985 186SL074930029 23 Dec 1985 - 28 Jan 1986;06 Feb 1987 - 01 Apr 1987 186SL074930030 27 Apr 1987 - 07 Jun 1987;31 Jan 1990 - 24 Feb 1990 186SL074930031Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 186SL074930032Units : millimeters Missing Data Flag :99999 186SL074930033Refernce Levl: All data are referred to a historic fixed 186SL074930034 bench mark (1951) 186SL074930035Comment : The daily or monthly means do not reveal any 186SL074930036 reference level shifts and agree well with Davao. 186SL074930037 186SL074930038 CI MISSING REPLACED GAPS QUESTIONABLE 186SL074930039YEAR (%) DATA OR BAD DATA FLUCTUATIONS 186SL074930040---- --- -------------------- --------------- -------------------- 186SL0749300411984 91 91-122 none none 186SL0749300421985 66 97-212,357-365 none 29-30,306,318,320, 186SL074930043 328 186SL0749300441986 92 1-28 none 88-90,253,358 186SL0749300451987 74 37-91,117-158 none 106-108 186SL0749300461988 95 140-160 none none 186SL0749300471989 100 none none 8-12,229,254,336, 186SL074930048 353-354 186SL0749300491990 42 31-59 none 92-93 186SL074930050 186SL074930051 QUALITY ASSESSMENT POLICY 186SL074930052 186SL074930053 The quality assessment is mostly based on the residuals 186SL074930054 (observed data minus predicted tides) of the hourly data. This 186SL074930055 assessment also applies to the daily and monthly data since 186SL074930056 they were derived from the quality-controlled hourly data. 186SL074930057 186SL074930058 The following abbreviations are used in the assessment: 186SL074930059 JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level 186SL074930060 Observing System; TOGA - Tropical Ocean Global Atmosphere 186SL074930061 research program; NODC - National Oceanographic Data Center; 186SL074930062 Instrmnt - instrument; Digitzd Intvl - digitized interval; 186SL074930063 Gaps > 1 mon - missing data in a span greater than one month; 186SL074930064 Refernce - reference. 186SL074930065 186SL074930066 The following corrections are made to the hourly data 186SL074930067 prior to this assessment: 186SL074930068 1) Gaps or obviously wrong data points in a span less than 186SL074930069 25 hours are filled by the predicted tide method*. 186SL074930070 2) Timing errors of exact increments of an hour are corrected 186SL074930071 by shifting the data. 186SL074930072 3) Reference level shifts are only corrected after information 186SL074930073 from tide staff readings or comparative readings with a fixed 186SL074930074 bench mark are checked to verify that the shift was not a 186SL074930075 natural event. If comparative readings are missing or 186SL074930076 incomplete, comparisons of the data with nearby stations 186SL074930077 may warrant the adjustment of some obvious shifts. 186SL074930078 4) Data with unresolved datum shifts are not disseminated. 186SL074930079 However, if sufficient time spans of data are available before 186SL074930080 or after the year(s) with the unresolved shift(s), a subset of 186SL074930081 quality assured data is made available. Thus, the Span field 186SL074930082 in the Quality Assessment may not match the span of the 186SL074930083 distribution data set. As the questionable datum shifts are 186SL074930084 resolved, the data set will be updated. Although this policy 186SL074930085 adds some complexity, it allows more rapid dissemination of 186SL074930086 at least the quality assured years. 186SL074930087 186SL074930088 For each year, the following information is documented from 186SL074930089 the quality-controlled hourly data with dates given as the nth 186SL074930090 day of the year starting from 1 January: 186SL074930091 1) a Completeness Index (CI) based on the percentage of hours 186SL074930092 with available data, 186SL074930093 2) a list of gaps longer than a day, 186SL074930094 3) a summary of days with consecutive missing or obviously 186SL074930095 wrong data in a time span longer than 6 but less than 25 186SL074930096 hours that have been replaced, with hours in parentheses, and 186SL074930097 4) a summary of days with questionable fluctuations in the 186SL074930098 residual series. Fluctuations within the residuals are 186SL074930099 considered significant and are noted if they are greater than 186SL074930100 25 cm. This policy has changed slightly as of October 1992: 186SL074930101 only suspicious fluctuations due to obvious instrumentation 186SL074930102 problems are noted. Minor timing drifts are no longer 186SL074930103 included in the list of questionable days. 186SL074930104 186SL074930105 Note : If the predicted tides poorly model the observed heights 186SL074930106 due to the inability of the tidal analysis to completely resolv 186SL074930107 the non-linear shallow water effects, the residuals are not 186SL074930108 suitable for assessing the data quality. Instead, a subjective 186SL074930109 comment on the quality of the data is provided. 186SL074930110 186SL074930111 *The predicted tides are obtained with the use of a harmonic 186SL074930112 analysis program (Foreman, 1977) which is executed on a year 186SL074930113 of apparently good data for a given station. The Predicted 186SL074930114 Tide Method for filling gaps consists of statistically 186SL074930115 comparing the predicted tides to the observed data and 186SL074930116 shifting the predicted tides in time to correct for timing 186SL074930117 differences. Then the linear interpolation between hourly 186SL074930118 values at the end points of the gap in the residual series is 186SL074930119 added to the corresponding corrected predicted tide data to 186SL074930120 obtain interpolated values over the span of the gap. 186SL074930121 186SL074930122 Bloomfield, P., 1976. Fourier Analysis of Time Series: An 186SL074930123 Introduction. New York: John Wiley and Sons. pp 129-137. 186SL074930124 186SL074930125 Foreman, M., 1977. Manual For Tidal Height Analysis and 186SL074930126 Prediction. Institute of Ocean Sciences, Patricia Bay, 186SL074930127 Victoria B.C. Pacific Marine Science Report 77-10. 186SL074930128 186SL07496 19841 1905000 1921000 198101099999999 2101010 2093000 186SL07496 19842 2097000 2095000 2078000 2082000 2013000 2027000 186SL07496 19851 1991000 1989000 1998000999999999999999999999999 186SL07496 19852 99999999 1974000 1987000 1996000 198400099999999 186SL07496 19861 99999999 1903000 1964000 1979000 1998000 1977000 186SL07496 19862 1961000 2015000 2004000 1992000 2021000 1948000 186SL07496 19871 19090009999999999999999 191405099999999 1957070 186SL07496 19872 1939000 1937000 1945000 1955000 1981000 1982000 186SL07496 19881 1936000 1933000 1992000 201500099999999 2013070 186SL07496 19882 2014000 2011000 2081000 2084000 2096000 2069000 186SL07496 19891 1974000 1993000 2072000 2087000 2085000 2067000 186SL07496 19892 2100000 2089000 2076000 2066000 1993000 1914000 186SL07496 19901 188901099999999 1888000 1958000 1962000 2047010 186SL07496 19902 999999999999999999999999999999999999999999999999