Title: Analyzing the dependence of global cloud feedback on the spatial pattern of sea surface temperature change with a Green's function approach

Abstract

The spatial pattern of sea surface temperature (SST) changes has a large impact on the magnitude of cloud feedback. In this study, we seek a basic understanding of the dependence of cloud feedback on the spatial pattern of warming. Idealized experiments are carried out with an AGCM to calculate the change in global mean cloud-induced radiation anomalies (ΔR_cloud) in response to imposed surface warming/cooling in 74 individual localized oceanic “patches”. Then the cloud feedback in response to a specific warming pattern can be approximated as the superposition of global cloud feedback in response to a temperature change in each region, weighted by the magnitude of the local temperature changes. When there is a warming in the tropical subsidence or extratropical regions, the local decrease of LCC results in a positive change in R_cloud. Conversely, warming in tropical ascent regions increases the free-tropospheric temperature throughout the tropics, thereby enhancing the inversion strength over remote regions and inducing positive global low-cloud cover (LCC) anomalies and negative Rcloud anomalies. The Green's function approach performs reasonably well in predicting the response of global mean ΔLCC and net ΔR_cloud, but poorly for shortwave and longwave components of ΔR_cloud due to its ineffectiveness in predicting middlemore » and high cloud cover changes. Finally, the approach successfully captures the change of cloud feedback in response to time-evolving CO₂-induced warming and captures the interannual variations in ΔR_cloud observed by CERES. The results highlight important nonlocal influences of SST changes on cloud feedback.« less

Authors:

Zhou, Chen  ^[1];

• Search OSTI.GOV for author "Zhou, Chen"
• Search OSTI.GOV for ORCID "0000-0003-3529-4283"
• Search orcid.org for ORCID "0000-0003-3529-4283"

Zelinka, Mark D.  ^[1];

• Search OSTI.GOV for author "Zelinka, Mark D."
• Search OSTI.GOV for ORCID "0000-0002-6570-5445"
• Search orcid.org for ORCID "0000-0002-6570-5445"

Klein, Stephen A.  ^[1]

• Search OSTI.GOV for author "Klein, Stephen A."
• Search OSTI.GOV for ORCID "0000-0002-5476-858X"
• Search orcid.org for ORCID "0000-0002-5476-858X"

---

+ Show Author Affiliations

1. Lawrence Livermore National Laboratory, Livermore California USA

Publication Date:

Thu Sep 14 00:00:00 EDT 2017

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1390341

Alternate Identifier(s):

OSTI ID: 1390342; OSTI ID: 1463011

Report Number(s):

LLNL-JRNL-733335
Journal ID: ISSN 1942-2466

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Journal Article: Published Article

Journal Name:

Journal of Advances in Modeling Earth Systems

Additional Journal Information:

Journal Name: Journal of Advances in Modeling Earth Systems Journal Volume: 9 Journal Issue: 5; Journal ID: ISSN 1942-2466

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; Green's function approach; cloud feedback; spatial pattern of warming