Tropical response to increased CO sub 2 in a GCM with a simple mixed layer ocean: Similarities to an observed Pacific warm event

Journal Article · Tue Apr 01 00:00:00 EST 1986 · Monthly Weather Review; (USA)

DOI:https://doi.org/10.1175/1520-0493(1986)114<0667:TRTICI>2.0.CO;2· OSTI ID:7017961

Meehl, G A; Washington, W M ^[1]

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1. National Center for Atmospheric Research, Boulder, CO (USA)

A version of the NCAR Community Climate Model (CCM), a global spectral atmospheric general circulation model, is coupled to a simple ocean mixed layer model with fixed depth. This mixed layer model is a simple slab of water that crudely accounts for seasonal heat storage but has no dynamics (e.g., advection, diffusion or upwelling). As a result, tropical sea surface temperatures (SSTs) produced by the simple mixed layer are warmer than observed in the equatorial tropics on the order of 1{degree}-2{degree}C. However, this uniform longitudinal warming is not associated with uniform longitudinal increases of tropical precipitation. Greatest area-averaged increases of precipitation occur in the tropical Pacific, while decreases of area-averaged precipitation are noted in the Asian monsoon regions. This is attributed to a disruption of the east-west circulation between the Pacific and Indian sectors similar to that observed during Pacific Warm Events. Accordingly, a number of the features of the model response to increased CO{sub 2} resemble those of a Warm Event. These include, for example, westerly upper-level wind anomalies in the subtropics of the pacific in both hemispheres, westerly similarities, it is emphasized that the real climate system may respond differently to an increase in CO{sub 2} due to the importance of tropical ocean dynamics that are not included in the present simple mixed-layer ocean model. The next step in the modeling hierarchy, an ocean GCM coupled to the NCAR CCM, will show how the response in the tropics, documented here for SSTs determined only by surface energy balance and crude ocean heat storage, may be affected by the addition of ocean dynamics.

• OSTI ID: 7017961
• Journal Information: Monthly Weather Review; (USA), Vol. 114; ISSN 0027-0644
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CARBON DIOXIDE
CLIMATE MODELS
ENVIRONMENTAL IMPACTS
GENERAL CIRCULATION MODELS
SURFACE WATERS
AMBIENT TEMPERATURE
TROPICAL REGIONS
CLIMATES
ATMOSPHERIC CIRCULATION
ATMOSPHERIC PRECIPITATIONS
ENERGY BALANCE
INDIAN OCEAN
PACIFIC OCEAN
SEAS
WIND
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
MATHEMATICAL MODELS
OXIDES
OXYGEN COMPOUNDS
540120* - Environment
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540310 - Environment
Aquatic- Basic Studies- (1990-)