On Cold Pool Collisions in Tropical Boundary Layers

Abstract

AbstractCollisions between cold pools are generally acknowledged to be important processes through which new convective cells are triggered. Yet relatively little has been done to characterize these processes in detail, quantify their impact on the life cycle of cold pools, and include them in convective parameterizations. We use a combination of Eulerian and Lagrangian models to investigate how much cold pools are affected by collisions. Results from simulations in radiative‐convective equilibrium suggest that collisions represent a first‐order process in the dynamics of cold pools, the median time of first collision being under 10 min since cold pool birth. Through a Lagrangian tracking algorithm, it is also shown that cold pools are significantly deformed by collisions and lose the circular shapes they would have if in isolation only a few minutes after birth. Finally, it is suggested that cold pools happen in clusters, and associated spatial and temporal scales are presented.