QUALITY ASSESSMENT OF SEA LEVEL DATA by the UH SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER JOINT ARCHIVE FOR SEA LEVEL updated: 07 Nov 2019 Station : Diego Garcia-D Latitude: 07 17.4S Country : United Kingdom Longitude: 072 23.6E JASL # : 104D Time Meridian: 90E (GMT + 6 hr) GLOSS # : 026 Originator #:104 NODC #: 30077202 Contributor : UH Sea Level Center 1000 Pope Rd. MSB 317 Honolulu, Hawaii 96822 Originator : UH Sea Level Center in collaboration with Naval Oceanographic Command Detachment F. P. O. San Fransisco, CA 96885-2905 Original Data: digital Instrmnt Type: 1) Aquatrak acoustic gauge (ECS), until Aug 2006 2) Handar Encoder 436A (ENC), in same well as the old Fisher and Porter ADR. 3) 2006- radar (RAD) gauge (Vega Vegapuls 62) 4) pressure transducer (PRS) Primary channel used in JASL set: 2003-2005: ECS 2006-: RAD *short gaps in primary channel filled with other channels as available; see UHSLC for specific dates Digitzd Intvl: 15 minutes (ENC); hourly and six minute (ECS) 3 min (RAD); 2 min (PRS) Present Data : Hourly, daily, and monthly values obtained by: Hourly : Three-point Hanning filter centered on the hour Daily : 119-point convolution filter (Bloomfield, 1976) centered on noon applied to the hourly data with respective periods of the 95, 50, and 5% amplitude points at 124.0, 60.2, and 40.2 hours Monthly: Simple average of all daily values; calculated if 7 or fewer days are missing Span of data : 26 Aug 2003 - 31 Dec 2018 Gaps > 1 mon : 26 Jan 2004 - 29 Mar 2004;02 Mar 2005 - 14 Apr 2005 14 Jun 2005 - 01 Oct 2005;02 Jan 2006 - 08 Sep 2006 20 May 2011 - 23 Jun 2011 Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 Units : millimeters Missing Data Flag : 9999 Existing : Yes Operational : Yes Sat. Trans. : Yes Distribution : 2003-2018 Refernce Levl: Heights are referred to the station tide staff zero, which is linked to land-based benchmarks. This reference zero is unique to this station and is not an official datum (chart, national, etc.) and is not relative to local tidal parameters, such as mean lower low water. See the Originators for benchmark descriptions, maps, and the geodetic levelling history. The sea level heights are referred to the zero point assigned to the new tide staff zero installed in 2003. A link has not been established to the zero reference of 1988-2000 (104C). Comment : The daily and monthly means do not reveal any reference level shifts or trends. 104A, 104B, 104C, and 104D are separate because each has a unique zero reference. JASL update NOV 2019 replaces 26 Aug 2003 - 05 Sep 2017. CI MISSING REPLACED GAPS QUESTIONABLE YEAR (%) DATA OR BAD DATA FLUCTUATIONS ---- --- -------------------- --------------- -------------------- 2003 24 289-318,342-354 none none 2004 75 26-89,162-164,201- none none 220,349-356 2005 53 61-104,109-128, none none 165-274 2006 32 2-251 none none 2007 100 none none none 2008 100 none none none 2009 100 none (07)123-(23)123 none 2010 100 none (13)089-(03)090 none (00)335-(07)335 2011 90 137-138,140-174 (16)132-(14)133 none (11)181-(18)181 2012 100 none (15)239-(01)240 none (14)269-(21)269 (22)320-(05)321 2013 99 177-179 (13)174-(23)174 none 2014 96 89-92,271-284 (02)276-(20)276 none (00)277-(23)277 2015 100 none none none 2016 100 none none none 2017 100 none none none 2018 98 211-218 (04)265-(15)265 none (18)265-(13)266