  Observations of coronal loops have identified several common loop
characteristics, including that loops appear to cool and have higher than
expected densities. Two potential heating scenarios have been suggested to
explain these observations. One scenario is that the loops are heated by a
series of small-scale impulsive heating events, or nanoflares. Another
hypothesis is that the heating is quasi-steady and highly-stratified, i.e.,
``footpoint heating'. The goal of this paper is to identify observables that
can be used to differentiate between these two heating scenarios. For footpoint
heating, we vary the heating magnitude and stratification, for impulsive
heating, we vary the heating magnitude. We use one-dimensional hydrodynamic
codes to calculate the resulting temperature and density evolution and expected
lightcurves in four channels of AIA and one channel of XRT. We consider two
principal diagnostics: the time lag between the appearance of the loop in two
different channels, and the ratio of the peak intensities of the loop in the
two channels. We find that 1) footpoint heating can predict longer time lags
than impulsive heating, 2) footpoint heating can predict zero or negative time
lags, 3) the intensity ratio expected from impulsive heating is confined to a
narrow range, while footpoint heating predicts a wider range of intensity
ratios, and 4) the range of temperatures expected in impulsive heating is
broader than the range of temperatures expected in footpoint heating. This
preliminary study identifies observables that may be useful in discriminating
between heating models in future work.
