Evaluation of a stochastic mixing scheme in the deep convective gray zone using a tropical oceanic deep convection case study

Total rainfall is modulated by a combination of mesoscale organization, areal coverage of convection, and convective intensity. The stochastic simulations tend to behave more similarly to the constant enhanced mixing simulation owing to greater impacts from enhanced mixing as compared to reduced mixing. The impacts of stochastic mixing are robust, ascertained by comparing the stochastic mixing ensembles with a non-stochastic mixing ensemble that has grid-scale noise added to the initial thermodynamic field.

Compared to radar observations and a higher resolution Delta h = 1 km simulation, stochastic mixing seemingly degrades the simulation performance. These results imply that stochastic mixing produces non-negligible impacts on convective system properties and evolution but does not lead to an improved representation of convective cloud characteristics in the case studied here.