  Our collective understanding of azimuthally-asymmetric features within the
coherent structure of a tropical cyclone (TC) continues to improve with the
availability of more detailed observations and high-resolution model outputs.
However, a precise understanding of how these asymmetries impact TC intensity
changes is lacking. Prior attempts at investigating the asymmetric impacts
follow a mean-eddy partitioning that condenses the effect of all the
asymmetries into one term and fails to highlight the differences in the role of
asymmetries at different scales. In this study, we present a novel
energetics-based approach to analyze the asymmetric impacts at multiple
length-scales during periods of TC rapid intensity changes. Using model outputs
of TCs under low and high shear, we compute the different energy pathways that
enhance/suppress the growth of multi-scale asymmetries in the wavenumber (WN)
domain. We then compare and contrast the energetics of the mean flow field (WN
0) with that of the persistent, coherent vortex-scale asymmetric structures
(WNs 1,2) and the more local, transient, sub-vortex-scale asymmetries (WNs
$\geq$ 3). We find in our case-studies that the dominant mechanisms of
growth/decay of the asymmetries are the baroclinic conversion from available
potential to kinetic energy at individual scales of asymmetries, and the
transactions of kinetic energy between the asymmetries of various
length-scales; rather than the barotropic mean-eddy transactions as is
typically assumed. Our case-study analysis further shows that the growth/decay
of asymmetries is largely independent of the mean. Certain aspects of eddy
energetics can potentially serve as early-warning indicators of TC rapid
intensity changes.
