Recent observations and modeling increasingly reveal the key role of
cold pools in organizing the convective cloud field.
Several methods for detecting cold pools in simulations exist, but are
usually based on buoyancy fields and fall short in reliably identifying
the active gust front.
The current algorithm, termed CoolDeTA, aims to detect and track cold
pools along with their active gust fronts and the “offspring” rain
cells generated nearby.
We show how CoolDeTA can reconstruct cold pool family trees.
Using it allows us to contrast RCE and diurnal cycle cold pool dynamics,
as well as cases with vertical wind shear and without.
The results suggest a conceptual model where cold pool triggering of
children rain cells follows a simple birth rate, which is proportional
to a cold pool’s gust front length.
The proportionality factor depends on the ambient atmospheric stability
and is lower for RCE, in line with marginal stability as traditionally
ascribed to the moist adiabat.
In the diurnal case, where ambient stability is lower, the birth rate
thus becomes substantially higher, in line with periodic insolation
forcing — resulting in essentially run-away mesoscale excitations
generated by a single parent rain cell and its cold pool.