Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published January 2022 | Submitted + Supplemental Material + Published
Journal Article Open

Seasonal Cycle of Idealized Polar Clouds: Large Eddy Simulations Driven by a GCM

Abstract

The uncertainty in polar cloud feedbacks calls for process understanding of the cloud response to climate warming. As an initial step toward improved process understanding, we investigate the seasonal cycle of polar clouds in the current climate by adopting a novel modeling framework using large eddy simulations (LES), which explicitly resolve cloud dynamics. Resolved horizontal and vertical advection of heat and moisture from an idealized general circulation model (GCM) are prescribed as forcing in the LES. The LES are also forced with prescribed sea ice thickness, but surface temperature, atmospheric temperature, and moisture evolve freely without nudging. A semigray radiative transfer scheme without water vapor and cloud feedbacks allows the GCM and LES to achieve closed energy budgets more easily than would be possible with more complex schemes. This enables the mean states in the two models to be consistently compared, without the added complications from interaction with more comprehensive radiation. We show that the LES closely follow the GCM seasonal cycle, and the seasonal cycle of low-level clouds in the LES resembles observations: maximum cloud liquid occurs in late summer and early autumn, and winter clouds are dominated by ice in the upper troposphere. Large-scale advection of moisture provides the main source of water vapor for the liquid-containing clouds in summer, while a temperature advection peak in winter makes the atmosphere relatively dry and reduces cloud condensate. The framework we develop and employ can be used broadly for studying cloud processes and the response of polar clouds to climate warming.

Additional Information

© 2021 The Authors. Journal of Advances in Modeling Earth Systems published by Wiley Periodicals LLC on behalf of American Geophysical Union. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. Issue Online: 03 January 2022; Version of Record online: 03 January 2022; Accepted manuscript online: 23 December 2021; Manuscript accepted: 16 December 2021; Manuscript revised: 10 December 2021; Manuscript received: 24 June 2021. X. Zhang was partially supported by an Advanced Study Program postdoctoral fellowship from the National Center for Atmospheric Research. Part of this material is based upon work supported by the National Center for Atmospheric Research, which is a major facility sponsored by the National Science Foundation under Cooperative Agreement No. 1852977. Part of this research was supported by the generosity of Eric and Wendy Schmidt by recommendation of the Schmidt Futures program and by the National Science Foundation (NSF grant AGS–1835860). Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The simulations were performed on Caltech's High Performing Cluster, which is partially supported by a grant from the Gordon and Betty Moore Foundation. Data Availability Statement: The GCM code is available online at https://doi.org/10.5281/zenodo.5773236 (Zhang et al., 2021b). The PyCLES code is available online at https://doi.org/10.5281/zenodo.5773210 (Zhang et al., 2021a). GCM forcing and LES output files are available at CaltechDATA repository https://doi.org/10.22002/D1.1429. The CERES EBAF Ed4.0 datasets were obtained from the NASA Langley Research Center CERES ordering tool at https://ceres.larc.nasa.gov/data/.

Attached Files

Published - J_Adv_Model_Earth_Syst_-_2021_-_Zhang_-_Seasonal_Cycle_of_Idealized_Polar_Clouds__Large_Eddy_Simulations_Driven_by_a_GCM.pdf

Submitted - essoar.10503204.1.pdf

Supplemental Material - 2021ms002671-sup-0001-supporting_information_si-s01.pdf

Files

J_Adv_Model_Earth_Syst_-_2021_-_Zhang_-_Seasonal_Cycle_of_Idealized_Polar_Clouds__Large_Eddy_Simulations_Driven_by_a_GCM.pdf

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023