  Here we present datasets of daily variation obtained from the geomagnetic
field raw observations recorded at the Coimbra Magnetic Observatory (COI,
Portugal) in 2007-2017, covering almost the entire solar cycle 24. Two methods
were used to extract daily variability from the raw geomagnetic hourly data.
The first method uses the so-called geomagnetically quiet days to calculate
S-type variations as daily means resulting in the data sub-set named IQD Sq and
SD. The second method uses the principal component analysis (PCA) to decompose
the original series into main variability modes. The first three modes produced
by PCA and explaining up to 98 per cent of the variability of the raw data are
in the data sub-set named PCA modes. Both methods allow to extract regular
geomagnetic field variations related to daily variations (S-type variations) in
the ionospheric dynamo region and some magnetospheric currents. The COI
location near the mean latitude of the ionospheric Sq current vortex focus
allows studying its variability using the S-type regular variations of the
geomagnetic field measured near the ground. The S-type variations for the X and
Y components of the geomagnetic field obtained at the COI observatory can also
be re-scaled and used to analyze field variations obtained at other European
geomagnetic observatories at close latitudes. The S-type variations for the Z
component of the geomagnetic field obtained at the COI observatory can be
compared to similar variations observed at more continental regions to study
the so-called coastal effect in the geomagnetic field variations. The dataset
described in this paper is analyzed in a companion paper Comparison of the
solar variations of the geomagnetic field at the Coimbra Magnetic Observatory
(COI) obtained by different methods: effect of the solar and geomagnetic
activity by A. Morozova and R. Rebbah submitted to ASR.
