GGP Repair Codes - updated 6 September 2011
The following information is extracted from Newsletter #5 ggpnews5.pdf 10 September 1997
An update concerning hourly files is extracted from Newsletter #19a ggpnews19a.pdf 22 May 2009
A GGP filename is of the form xxyymmcc.ggp, where
xx = station name (e.g. ST)
yy = year (e.g. 07)
mm = month (e.g. 03)
cc = repair code (e.g. 00)
The repair code is used to specify what has happened to the data. It generally means one of 3 things:
linear
interpolation of full signal across spikes or gaps, generally when only a
few points are involved
linear
interpolation of residual signal (when tides and atmospheric pressure are
removed), generally for longer gaps or periods of obvious instrument
disturbance
removal of offsets in the residual signal, generally where there is a clear jump of non-geophysical origin (such as a power surge due to lightening)
Code |
significance |
|
00 |
raw data (as recorded), decimated to 1 min |
no repair prior to decimation (GGP STANDARD). As of September 2008, it was agreed that very short gaps or spikes shorter than about 10 sec can be filled by linear interpolation between good data points on the raw data (full signal), prior to decimation. This will avoid unnecessary spreading of minor problems through the filtering and decimation procedure to 1 minute data. Data (gravity and pressure) processed in this way can still be given the '00' code. |
01 |
gaps and disturbances filled with synthetic signal |
repair done on raw data, before decimation to 1 min |
02 |
as 01 + offsets adjusted |
as above... |
11 |
gaps and disturbances filled with synthetic signal |
repair done by station operator on data after decimation to 1 min |
12 |
as 11 + offsets adjusted |
as above ... |
21 |
gaps and disturbances filled with synthetic signal |
repair done by staff at ICET*, prior to tidal analysis |
22 |
as 21 + offsets adjusted |
as above ... |
h1 |
data processed by user |
one hour data decimated from 1 min |
h2 |
data processed by ICET* |
as above, but done by staff at ICET* |
*International Center for Earth Tides. Note the data is already multiplied by the appropriate calibration factors.