Davao (Philippines) Data Quality Assessment

Quality Assessment of sea level data by the TOGA Sea Level Center/National Oceanographic Data Center Joint Archive for Sea Level.

Station Davao Latitude 07° 05.0' N
Country Philippines Longitude 125° 38.0' E
JASL # 372A Time Meridian: 120E (GMT + 8 hr)
GLOSS # 071 TOGA # P009
NODC # 10127501
Contributor: Oceanographic Surveys Division NAMRIA, Binondo Branch P. O. Box 1620 Manila, Philippines
Originator: Same
Original Data: Analog
Instrument Type: A.OTT, gravity type
Digitzd Interval: One hour
Present Data: Hourly, daily, and monthly values obtained by:
Hourly: The original digitizing interval was hourly
Daily: 119-point convolution filter (Bloomfield, 1976) centred 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: 01 January 1984 - 30 June 1990
Gaps >1 Month: None
Time Reference: GMT (hours 00-23)
Space-filler Flag: -9999
Units: Millimeters
Missing Data Flag: 99999
Reference Level: All data are referred to a historic fixed bench mark (1951)
Comment: A suspicious signature exists in 1986. It appears from the daily averages to be a reference level shift of about 20 cm on 30 November. A similar feature of less magnitude exists at the same time for Jolo and Legaspi; thus the possibility of the suspicious signature being real exists. The originators have confirmed that no errors were obvious in the analog chart or processing. The numerous questionable fluctuations below may be a result of inaccurate timing of the gauge and/or from the tidal analysis not being able to resolve certain harmonics. Typhoon activity did not pass near.