Investigating aspects of the transition from shallow to deep convection with a Lagrangian particle model

The transition from shallow to deep convection constitutes an important process in the climate system and, since a profound understanding of the mechanisms controlling it is still lacking, its correct representation in Global Climate Models is a major challenge for climate modeling. Cold pools, one of the main ingredients of deep convective regimes, have been suggested to play a major role in the transition from shallow to deep convection and have been the focus of many studies lately. One topic of interest is the different mechanisms through which cold pools can trigger new convective cells and which dominate in different scenarios. This problem, together with a detailed characterization of cold pools, can be addressed using a Lagrangian particle model. Here, an algorithm is presented to use this model to identify and track cold pools and their properties as they evolve and also to track air parcels as they are convectively triggered in the sub-cloud layer. Through the tracking, the algorithm provides information on the nature of the triggering and the role cold pools play in the process. Statistics carried out over a collection of parcels obtained from different cases, over land and over ocean, are then discussed.