How does a convection cluster respond to a large-scale mean wind?

Atmospheric convection can spontaneously cluster and confine within an envelope. These clusters of convection often propagate under the influence of a large-scale mean wind, such as the Madden-Julian oscillation (MJO). The motivation of this study is to understand how a large-scale mean wind influences the propagation of a convection cluster. To this end, we investigate the response of convective self-aggregation, a model depiction of a convection cluster in radiative-convective equilibrium (RCE), to a wind perturbation. We impose a constant mean wind on an aggregated convective system (obtained through a simulation without mean wind) and observe its evolution in a three-dimensional cloud-resolving model. We note in our modeling experiments that convection clusters exhibit a propagating behavior under a large-scale mean wind, albeit with a speed that is less than the prescribed forcing. We find that surface fluxes are critical in slowing down the convection clusters. Enthalpy and momentum fluxes slow down the convection cluster with comparable effects through different mechanisms. Enthalpy fluxes favor convection upwind through the wind-induced surface heat exchange (WISHE) feedback, opposing the convection cluster movement. Momentum flux acts as a negative feedback on surface winds in places of strongest near-surface winds.