Bitung (Indonesia) 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 Bitung Latitude 01° 26.4' N
Country Indonesia Longitude 125° 11.6' E
JASL # 033A Time Meridian 120° E (GMT + 8 hr)
GLOSS # 069 TOGA # P007
NODC # 10121501
Contributor: BAKOSURTANAL, Indonesia J. Raya Jakarta - Borog Km 46 P.O. Box 46 Cibinong, Indonesia
Originator: Same
Original Data: Digital
Instrument Type: Fischer and Porter Analog-to-Digital Recorder
Digitized Interval: 15 minutes
Present Data: Hourly, daily, and monthly values obtained by:
Hourly: (pre-1987) Nine-point triangular filter centred on the hour with respective periods of the 95, 50, and 5% amplitude point of the filter response at 623.6, 177.0, and 103.7 minutes;(1987+) three-point Hanning filter centered on the hour
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: 14 December 1986 - 30 December 1990
Gaps >1 Month: None
Time Reference: GMT (hours 00-23)
Space-filler Flag: -9999
Units: Millimeters
Missing Data Flag: 99999
Reference Level: All heights have been referred to the station tide staff zero which is linked to fixed bench marks
Comment: The daily and monthly means reveal no apparent changes in the reference level. The residuals (observed data minus predicted tides) have spikes periodically. However, the installation is in a region with complex tides that the harmonic analysis can not completely resolve, which may explain this spikey signature.