资源环境科技发展态势分析平台

Collisions 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 10min 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.

Plain Language Summary While collisions between cold pools are known to be key processes in the formation of new convective clouds, they are overlooked by many studies and most parameterizations. We find that collisions have a significant impact on the life and the dynamics of cold pools, affecting their propagations in the boundary layer already few minutes after their birth. Contrary to many conceptual models, our results suggest that cold pools lose circular symmetry already when still young. Finally, we show that cold pools are not randomly distributed in space and time but tend to appear in clusters.