Cold pool collisions as a triggering mechanism of convection

Cold pools are produced by rain evaporation from
convective thunderstorms and play an important role 
in many atmospheric phenomena (e.g. transition to deep convection and convective self-aggregation). From observational
and numerical studies, it has been found that intersecting cold pools
increase the likelihood of triggering convection.
We test this hypothesis by combining observational
radar data from Darwin (Australia) with a simple conceptual model.

We identify precipitation objects in the radar data. It is assumed that each rain event produces a cold pool
that is initialized at the center of the precipitation cell. Cold pools are simulated with a stochastic surface growth model.
The spatial coordinate of each collision event is recorded. 
Collectively these points take the shape of a Voronoi diagram. 
According to our hypothesis, the probability of new rain events should decay with spatial distance to the Voronoi.

Our preliminary results suggest that rain events cluster in the
vicinity of the Voronoi with a higher frequency that one would expect if cold pool collisions did not stimulate convection. 
To conclude, our findings suggest that dynamic collisions between cold pools increase the likelihood of convection in the surrounding area.
This work allows us to study the effect of cold pools from radar data, despite cold pools being invisible to the radar images,
using a simple object-based model of convective cold pools.