QUALITY ASSESSMENT OF SEA LEVEL DATA by the UH SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER JOINT ARCHIVE FOR SEA LEVEL Station : Mazatlan Latitude: 23 11.9N Country : Mexico Longitude: 106 25.3W JASL # : 673A Time Meridian: 105W (GMT - 7 hr) GLOSS # : none TOGA #: none NODC #: 72103601 Contributor : Servicio Mareografico Nacional Instituto de Geofisica Universidad Nacional Autonoma de Mexico 04510 Mexico, D. F. MEXICO Originator : same Original Data: analog Instrmnt Type: standard gauge with float and stilling well Digitzd Intvl: hourly to tenths of feet Present Data : Hourly, daily, and monthly values obtained by: Hourly : spot sample on the hour from the analog roll 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 : 02 Jan 1953 - 28 Jun 1975 Gaps > 1 mon : 01 Dec 1956 - 02 Feb 1957;01 Sep 1957 - 01 Oct 1957 26 Jun 1961 - 11 Sep 1961 Time Refernce: GMT (hours 00-23) Space-filler Flag :-9999 Units : millimeters Missing Data Flag : 9999 Existing : Yes Operational : Yes Sat. Trans. : No Distribution : 1953-1975 Refernce Levl: The data are referred to tide staff zero which is linked to fixed bench marks. However, comparisons with neighboring sites and examination of the hourly residuals has lead to the following adjustment: period value added ( (hour)day/month/year ) to original(mm) --------------------------- --------------- (20)21/10/57 - (20)20/11/57 180 Comment : The daily and monthly values do not reveal any obvious reference level shifts or trends and agree fairly well with Manzanillo. A suspicious drop on 12/Oct/72 and rise on 02/Nov/72 of about 15 cm agrees relatively well with other sites and is apparently a true signal. Notable episodic events: 23-25 May 1960: Tsunami from S.C. Chile 28 Mar 1964: Tsunami from Alaska CI MISSING REPLACED GAPS QUESTIONABLE YEAR (%) DATA OR BAD DATA FLUCTUATIONS ---- --- -------------------- --------------- -------------------- 1953 99 1 none 54-55 1954 100 none none 199-363 1955 100 none none none 1956 92 336-366 none none 1957 83 1-32,244-274 none none 1958 96 127-142 none 91,318,327-331,341- 342,358 1959 98 40-49,365 (07)001-(06)002 10-11 (11)062-(23)062 (07)302-(19)302 1960 100 none (18)310-(05)311 144-146,336-337 1961 79 177-254 none none 1962 100 none (07)001-(06)002 6-9,91-92,151 1963 98 1-7 none 142,192-193 1964 100 none (22)088-(08)089 none (09)236-(18)236 1965 100 none (02)071-(09)071 none (21)132-(04)133 (12)269-(23)269 1966 100 none (22)303-(06)304 none 1967 100 none (12)028-(19)028 188-191 (19)270-(05)271 1968 100 none (21)069-(04)070 none (09)102-(16)102 (00)134-(09)134 (17)256-(12)257 (07)339-(15)339 1969 100 none (00)344-(21)344 236-237 1970 100 none (22)174-(12)175 none 1971 100 none (07)107-(16)107 none 1972 100 none (06)034-(22)034 none (15)074-(22)074 (00)091-(18)091 (08)211-(22)211 (15)325-(23)325 1973 100 none none none 1974 100 none (15)198-(08)199 none (20)266-(14)267 1975 48 none none none