Title: 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 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. Furthermore, 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 mainmore » 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.« less

Authors:

Zhang, Xiyue  ^[1];

• Search DOE PAGES for author "Zhang, Xiyue"
• Search DOE PAGES for ORCID "0000-0002-6031-7830"

Schneider, Tapio  ^[2];

• Search DOE PAGES for author "Schneider, Tapio"
• Search DOE PAGES for ORCID "0000-0001-5687-2287"

Shen, Zhaoyi  ^[3];

• Search DOE PAGES for author "Shen, Zhaoyi"
• Search DOE PAGES for ORCID "0000-0002-0444-4720"

Pressel, Kyle G.  ^[4];

• Search DOE PAGES for author "Pressel, Kyle G."
• Search DOE PAGES for ORCID "0000-0002-4538-3055"

Eisenman, Ian  ^[5]

• Search DOE PAGES for author "Eisenman, Ian"
• Search DOE PAGES for ORCID "0000-0003-0190-2869"

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+ Show Author Affiliations

1. Johns Hopkins Univ., Baltimore, MD (United States)
2. California Institute of Technology (CalTech), Pasadena, CA (United States); California Institute of Technology (CalTech), Pasadena, CA (United States). Jet Propulsion Lab. (JPL)
3. California Institute of Technology (CalTech), Pasadena, CA (United States)
4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
5. Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography

Publication Date:

Thu Dec 23 00:00:00 EST 2021

Research Org.:

Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE; National Science Foundation (NSF)

OSTI Identifier:

1847560

Report Number(s):

PNNL-SA-167085
Journal ID: ISSN 1942-2466

Grant/Contract Number:  

AC05-76RL01830; 1852977; AGS-1835860

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Advances in Modeling Earth Systems

Additional Journal Information:

Journal Volume: 14; Journal Issue: 1; Journal ID: ISSN 1942-2466

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; cloud; LES; Arctic; seasonal cycle; mixed-phase cloud; GCM