  In this work we investigate the global activity patterns predicted from a
model active region heated by distributions of nanoflares that have a range of
frequencies. What differs is the average frequency of the distributions. The
activity patterns are manifested in time lag maps of narrow-band instrument
channel pairs. We combine hydrodynamic and forward modeling codes with a
magnetic field extrapolation to create a model active region and apply the time
lag method to synthetic observations. Our aim is not to reproduce a particular
set of observations in detail, but to recover some typical properties and
patterns observed in active regions. Our key findings are the following. 1.
cooling dominates the time lag signature and the time lags between the channel
pairs are generally consistent with observed values. 2. shorter coronal loops
in the core cool more quickly than longer loops at the periphery. 3. all
channel pairs show zero time lag when the line-of-sight passes through coronal
loop foot-points. 4. there is strong evidence that plasma must be re-energized
on a time scale comparable to the cooling timescale to reproduce the observed
coronal activity, but it is likely that a relatively broad spectrum of heating
frequencies are operating across active regions. 5. due to their highly dynamic
nature, we find nanoflare trains produce zero time lags along entire flux tubes
in our model active region that are seen between the same channel pairs in
observed active regions.
