  Aims. Understanding the activity is vital for deciphering the structure,
formation, and evolution of comets. We investigate models of cometary activity
by comparing them to the dynamics of 67P/Churyumov-Gerasimenko. Methods. We
matched simple thermal models of water activity to the combined Rosetta
datasets by fitting to the total outgassing rate and four components of the
outgassing induced non-gravitational force and torque, with a final manual
adjustment of the model parameters to additionally match the other two torque
components. We parametrised the thermal model in terms of a distribution of
relative activity over the surface of the comet, and attempted to link this to
different terrain types. We also tested a more advanced thermal model based on
a pebble structure. Results. We confirm a hemispherical dichotomy and
non-linear water outgassing response to insolation. The southern hemisphere of
the comet and consolidated terrain show enhanced activity relative to the
northern hemisphere and dust-covered, unconsolidated terrain types, especially
at perihelion. We further find that the non-gravitational torque is especially
sensitive to the activity distribution, and to fit the pole-axis orientation in
particular, activity must be concentrated (in excess of the already high
activity in the southern hemisphere and consolidated terrain) around the south
pole and on the body and neck of the comet over its head. This is the case for
both the simple thermal model and the pebble-based model. Overall, our results
show that water activity cannot be matched by a simple model of sublimating
surface ice driven by the insolation alone, regardless of the surface
distribution, and that both local spatial and temporal variations are needed to
fit the data.
