Midlatitude atmosphere-ocean interaction during El Nino. Part I. The north Pacific ocean

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Journal of Climate; (United States)

DOI:https://doi.org/10.1175/1520-0442(1992)005<0944:MAIDEN>2.0.CO;2· OSTI ID:6617184

Alexander, M A ^[1]

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1. Univ. of Wisconsin, Madison (United States)

Atmosphere-ocean modeling experiments are used to investigate the formation of sea surface temperature (SST) anomalies in the North Pacific Ocean during fall and winter of the El Nino year. Experiments in which the NCAR Community Climate Model (CCM) surface fields are used to force a mixed-layer ocean model in the North Pacific (no air-sea feedback) are compared to simulations in which the CCM and North Pacific Ocean model are coupled. Anomalies in the atmosphere and the North Pacific Ocean during El Nino are obtained from the difference between simulations with and without prescribed warm SST anomalies in the tropical Pacific. In both the forced and coupled experiments, the anomaly pattern resembles a composite of the actual SST anomaly field during El Nino: warm SSTs develop along the coast of North America and cold SSTs form in the central Pacific. In the coupled simulations, air-sea interaction results in a 25% to 50% reduction in the magnitude of the SST and mixed-layer depth anomalies, resulting in more realistic SST fields. Coupling also decreases the SST anomaly variance; as a result, the anomaly centers remain statistically significant even though the magnitude of the anomalies is reduced. Three additional sensitivity studies indicate that air-sea feedback and entrainment act to damp SST anomalies while Ekman pumping has a negligible effect on mixed-layer depth and SST anomalies in midatitudes.

• OSTI ID: 6617184
• Journal Information: Journal of Climate; (United States), Journal Name: Journal of Climate; (United States) Vol. 5:9; ISSN JLCLEL; ISSN 0894-8755
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
540310 -- Environment
Aquatic-- Basic Studies-- (1990-)
AIR
ATMOSPHERIC CIRCULATION
CLIMATE MODELS
COUPLING
ENTRAINMENT
FEEDBACK
FLUIDS
FUNCTIONAL MODELS
GASES
MATHEMATICAL MODELS
MONITORING
NORTH AMERICA
OCEANIC CIRCULATION
PACIFIC OCEAN
SEAS
SEASONAL VARIATIONS
SENSITIVITY
SOUTHERN OSCILLATION
SURFACE WATERS
TEMPERATURE MEASUREMENT
VARIATIONS