Modeling of Cloud Droplet Formation: Software Development and Sampling Strategies

Abstract

Updraft speeds are an important factor in the formation of cloud droplets which play an important role in an atmospheric simulation. The updraft speeds are varying very strongly in small areas of space. Current models do not account for this kind of variability. Support for a probability density function (PDF) based approach in representing the variability of the updraft speeds has been implemented in the Energy Exascale Earth System Model (E3SM). Specifics of the implementation process have been discussed. Different sampling strategies were tested to analyze the convergence behavior of the new approach to the cloud droplet formation process. It has shown that using a simple Monte Carlo sampling strategy has given good convergence rates for the different variables that are important to the cloud droplet formation process.