Midlatitude atmosphere-ocean interaction during El Nino. Part II. The northern hemisphere atmosphere

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

DOI:https://doi.org/10.1175/1520-0442(1992)005<0959:MAIDEN>2.0.CO;2· OSTI ID:6619612

Alexander, M A ^[1]

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

The influence of midlatitude air-sea interaction on the atmospheric anomalies associated with El Nino is investigated by coupling the Community Climate Model to a mixed-layer ocean model in the North Pacific. Prescribed El Nino conditions, warm sea surface temperatures (SST) in the tropical Pacific, cause a southward displacement and strengthening of the Aleutian Low. This results in enhanced (reduced) advection of cold Asian air over the west-central (northwest) Pacific and northward advection of warm air over the eastern Pacific. Allowing air-sea feedback in the North Pacific slightly modified the El Nino-induced near-surface wind, air temperature, and precipitation anomalies. The anomalous cyclonic circulation over the North Pacific is more concentric and shifted slightly to the east in the coupled simulations. Air-sea feedback also damped the air temperature anomalies over most of the North Pacific and reduced the precipitation rate above the cold SST anomaly that develops in the central Pacific. The simulated North Pacific SST anomalies and the resulting Northern Hemisphere atmospheric anomalies are roughly one-third as large as those related to the prescribed El Nino conditions in a composite of five cases. The composite geopotential height anomalies associated with changes in the North Pacific SSTs have an equivalent barotropic structure and range from -65 m to 50 m at the 200-mb level. Including air-sea feedback in the North Pacific tended to damp the atmospheric anomalies caused by the prescribed El Nino conditions in the tropical Pacific. As a result, the zonally elongated geopotential height anomalies over the West Pacific are reduced and shifted to the east. However, the atmospheric changes associated with the North Pacific SST anomalies vary widely among the five cases.

• OSTI ID: 6619612
• Journal Information: Journal of Climate; (United States), Vol. 5:9; ISSN 0894-8755
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ATMOSPHERIC CIRCULATION
VARIATIONS
PACIFIC OCEAN
OCEANIC CIRCULATION
TEMPERATURE MEASUREMENT
ADVECTION
AIR
AMBIENT TEMPERATURE
CLIMATE MODELS
COUPLING
FEEDBACK
FUNCTIONAL MODELS
NORTHERN HEMISPHERE
PRECIPITATION
SEAS
SEASONAL VARIATIONS
SOUTHERN OSCILLATION
SURFACE AIR
WIND
EARTH PLANET
FLUIDS
GASES
MASS TRANSFER
MATHEMATICAL MODELS
PLANETS
SEPARATION PROCESSES
SURFACE WATERS
540110*
540310 - Environment
Aquatic- Basic Studies- (1990-)