Quantifying Uncertainty and Constraining Parameterizations of Clouds in Earth System Modelsusing NASA Observations

Lead PI: Dr. Marcus van Lier-Walqui

Unit Affiliation: Center for Climate Systems Research (CCSR)

Unit Affiliation: NASA Goddard Institute for Space Studies (GISS)

July 2021 - July 2025
Project Type: Research

DESCRIPTION: The proposed research will perform perturbed-parameter ensemble-based (PPE) model development and tuning for the NASA GISS ModelE, NASA GEOS, and CESM global climate models. This will leverage previous work by Dr. van Lier-Walqui and Dr. Elsaesser (Co-Is on the current proposal) in application of a similar approach to ModelE. In addition, it will utilize a Bayesian approach to cloud microphysics developed by Dr. van Lier-Walqui and external Co-I Dr. Hugh Morrison (NCAR). The proposed approach is a state-of-the-art attempt at improving the fidelity and physical realism of climate models.

In year one, Dr. van Lier-Walqui will work with Dr. Morrison to further refine and develop the cloud microphysics scheme in question (BOSS) using detailed process-level “box-model” simulations.

In year two, Dr. van Lier-Walqui will work with Dr. Morrison to continue development of BOSS in kinematic column experiments. Drs. Elsaesser and van Lier-Walqui will set up initial perturbed-parameter ensemble experiments in the “default” version of ModelE. Dr. Elsaesser will collaborate with Co-Is Morrison and PI Gettelman to implement BOSS into ModelE, and will set up observational datasets for use in model comparison.

In year three, Dr. van Lier-Walqui will test and optimize the PPE methodology, including by testing various artificial neural network configurations, and optimizing the Markov Chain Monte Carlo sampler used to provide parameter estimates. Dr. Elsaesser will set up single-column model tests using the version of ModelE with BOSS, and also make initial tests of global simulations using this configuration. Dr. van Lier-Walqui will assist and advise with PPE for the single-column model runs.

In year four, Dr. van Lier-Walqui and Dr. Eslaesser will set up and run full global-simulation PPE model tuning experiments with the BOSS configuration of ModelE, and analyze and intercompare results with those using GEOS and CESM.