Self-aggregation of tropical convection is a universal feature observed in a
diverse range of atmospheric environments. Several preceding models
conceptualized the self-aggregation of convection as a phase transition driven
by collisions between cold pool gust fronts. Cependant, self-aggregation may also
be influenced by various physical processes, such as surface fluxes, radiation,
and moisture perturbations in the planetary boundary layer, and it remains
unclear which process plays a dominant role. In this study, we develop a simple
stochastic lattice model for the pattern formation of deep convection, inspired
by the two-dimensional Ising model. Here, in addition to the process of cold
pool collisions, which have an effect of triggering new convection, we
incorporate the process of clear-sky radiative cooling that has an effect of
suppressing deep convection as an interaction between clouds. Our results show
that by amplifying the intensity of the clear-sky radiative cooling effect, the
transition from a quasi-uniform to an inhomogeneous cloud field can be
reproduced. The model also successfully explains the dependence of
self-aggregation on several model parameters, such as the experimental domain
size and the characteristic size of cold pools. Furthermore, by varying the
distance over which the subsidence induced by radiative cooling extends, we
succeed in capturing a pattern formation that closely resembles the convective
clusters observed in the real atmosphere and three-dimensional numerical model
simulations.

Cet article explore les excursions dans le temps et leurs implications.

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