This is a project funded by the National Science Foundation.

Project Leads

PI: Adele Igel
co-PI: Marcus van Lier-Walqui
co-PI: Mikael Witte
co-PI: Kaitlyn Loftus
Collaborator: Hugh Morrison
Collaborator: Kamal Kant Chandrakar
Collaborator: Tomislava Vukicevic

Project Summary

The objectives of the proposed work are to understand the microphysical sources of spatial variability in low-level stratocumulus clouds, how this spatial variability influences the temporal evolution of the mean cloud and precipitation processes, and how our design of microphysics parameterizations influences our ability to simulate the observed spatial structure of these cloud and precipitation fields. We hypothesize that cloud and precipitation variability is at the core of simple (bulk) microphysics scheme deficiencies. We will meet these objectives and test the hypothesis through a combination of modeling with both highly complex and relatively simple microphysics schemes (Lagrangian particle and bulk schemes, respectively) and observational analysis. Lagrangian particle schemes are the only schemes that can currently reproduce the observed spatial structure of low clouds. As such, we will leverage stratocumulus simulations with a Lagrangian particle scheme to systematically test the importance of various microphysical processes for the development of spatial variability in the cloud and precipitation fields. We will also use Lagrangian particle simulations to train the Bayesian Observationally-constrained Statistical-physical Scheme (BOSS) with special attention to those processes identified as important for generating the observed spatial structure. BOSS will be developed with both stochastic and non-stochastic processes. Test simulations run with BOSS will provide insight into how microphysics schemes should be designed to simulate the observed spatial structure and will allow us to directly test our hypothesis.