  We introduce the concept of a Background-subtracted Solar Activity Map
(BaSAM) as a new quantitative tool to assess and visualize the temporal
variation of the photospheric magnetic field and the UV 160 nm intensity. The
method utilizes data of the Solar Dynamics Observatory (SDO) and is applicable
to both full-disk observations and regions-of-interest. We illustrate and
discuss the potential of BaSAM resorting to datasets representing solar minimum
and maximum conditions: (1) Contributions of quiet-Sun magnetic fields, i.e.
the network and (decaying) plage, to solar activity can be better determined
when their variation is measured with respect to the background given by "deep"
magnetograms. (2) Flaring and intermittent brightenings are easily appraised in
BaSAMs of the UV intensity. (3) Both magnetic-field and intensity variations
demonstrated that the flux system of sunspots is well connected to the
surrounding supergranular cells. In addition, producing daily full-disk BaSAMs
for the entire mission time of SDO provides a unique tool to analyze solar
cycle variations, showing how vigorous or frail are the variations of
magnetic-field and intensity features.
