Title: Cloud transitions: comparison of temporal variation in the southeastern Pacific with the spatial variation in the northeastern Pacific at low latitudes

Abstract

ABSTRACT The seasonal variation of clouds in the southeastern equatorial Pacific ( SEP ) is analysed and compared with the spatial variation of clouds in the northeastern Pacific along the Global Energy and Water Cycle Experiment Cloud System Study/Working Group on Numerical Experimentation ( GCSS / WGNE ) Pacific Cross‐Section Intercomparison ( GPCI ) transect. A ‘seasonal cloud transition’ – from stratocumulus to shallow cumulus and eventually to deep convection – is found in the SEP from September to April, which is similar to the spatial cloud transition along the GPCI transect from the California coast to the equator. It is shown that this seasonal cloud transition in the SEP is associated with increasing sea surface temperature ( SST ), decreasing lower tropospheric stability and large‐scale subsidence, which are all similar to the spatial variation of these fields along the GPCI transect. Difference is found that the SEP cloud transition is associated with decreasing surface wind speed and surface latent heat flux, weaker larger‐scale upward motion and convective instability, which lead to less deepening of the low clouds and less frequent deep convection than those in the GPCI transect. The seasonal cloud transition in the SEP provides a test for climate models to simulatemore » the relationships between clouds and large‐scale atmospheric fields in a region that features a spurious double inter‐tropical convergence zone ( ITCZ ) in most models.« less

Authors:

Yu, Haiyang ^[1]; Zhang, Minghua  ^[2];

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Lin, Wuyin ^[3]; Zhang, Xiaoxiao ^[4]

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+ Show Author Affiliations

1. School of Marine and Atmospheric Sciences Stony Brook University NY USA
2. School of Marine and Atmospheric Sciences Stony Brook University NY USA, ICCES Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences Beijing China
3. Brookhaven National Laboratory Upton NY USA
4. ICCES Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences Beijing China, College of Earth Science University of Chinese Academy of Sciences Beijing China

Publication Date:

Fri Oct 14 00:00:00 EDT 2016

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1328966

Alternate Identifier(s):

OSTI ID: 1328967; OSTI ID: 1392222

Report Number(s):

BNL-114209-2017-JA
Journal ID: ISSN 0899-8418

Grant/Contract Number:  

SC0012704

Resource Type:

Published Article

Journal Name:

International Journal of Climatology

Additional Journal Information:

Journal Name: International Journal of Climatology Journal Volume: 37 Journal Issue: 6; Journal ID: ISSN 0899-8418

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

United Kingdom

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; cloud transition; GPCI; southeastern equatorial Pacific; marine boundary layer; deep convection