Cloud transitions: comparison of temporal variation in the southeastern Pacific with the spatial variation in the northeastern Pacific at low latitudes
[2];
- School of Marine and Atmospheric Sciences Stony Brook University NY USA
- School of Marine and Atmospheric Sciences Stony Brook University NY USA, ICCES Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences Beijing China
- Brookhaven National Laboratory Upton NY USA
- ICCES Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences Beijing China, College of Earth Science University of Chinese Academy of Sciences Beijing China
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 simulate 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.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0012704
- OSTI ID:
- 1328966
- Alternate ID(s):
- OSTI ID: 1328967; OSTI ID: 1392222
- Report Number(s):
- BNL-114209-2017-JA
- Journal Information:
- International Journal of Climatology, Journal Name: International Journal of Climatology Vol. 37 Journal Issue: 6; ISSN 0899-8418
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- United Kingdom
- Language:
- English
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