Simulations of precipitation and atmospheric circulation changes associated with warm SSTs: Results from an ensemble of long term integrations with idealized anomalies

Journal Article · Wed Apr 01 00:00:00 EST 1992 · Climate Dynamics; (United States)

DOI:https://doi.org/10.1007/BF00211156· OSTI ID:6535103

Smith, I N; Gordon, H B ^[1]

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1. Commonwealth Scientific and Industrial Research Organization, Victoria (Australia)

A general circulation model is used to simulate the atmospheric response to a prescribed, idealized time varying warm sea surface temperature anomaly (SSTA) in the equatorial Pacific characteristic of ENSO events. The model incorporates the full seasonal cycle and an ensemble of five anomaly simulations, each of 14 months duration, is performed and the results compared with those from a ten year control simulation involving climatological SSTS. In a test of the model, simulated perturbations to precipitation patterns are compared with the analysis by Ropelewski and Halpert which identifies regions where precipitation perturbations are associated with the ENSO cycle. Strong and statistically significant perturbations are simulated throughout much of the equatorial Pacific and the Australian region which agree with the analysis. Perturbations over the Americas and the Indian sub-continent show part agreement with observations, while elsewhere, at more remote and high latitude locations, there is less agreement, providing some indication of model limitations in simulating the hydrological cycle. Over the equatorial Pacific most of the anomalous precipitation is accounted for by moisture flux convergence. Only in the vicinity of the maximum anomaly, located in the eastern Pacific, do warmer SSTs contribute to the perturbed circulation. Elsewhere, anomalous wind speeds mainly determine anomalous heat fluxes. As a result, the large scale perturbations to wind, moisture and precipitation appear to be forced indirectly, rather than directly as assumed in simple ocean-atmosphere models.

• OSTI ID: 6535103
• Journal Information: Climate Dynamics; (United States), Vol. 7:3; ISSN 0930-7575
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
SOUTHERN OSCILLATION
GENERAL CIRCULATION MODELS
SURFACE WATERS
TEMPERATURE MEASUREMENT
ATMOSPHERIC CIRCULATION
AUSTRALIA
EQUATOR
HEAT
INDIA
NORTH AMERICA
PRECIPITATION
SEAS
SEASONAL VARIATIONS
SOUTH AMERICA
TEMPERATURE DEPENDENCE
WIND
ASIA
AUSTRALASIA
DEVELOPED COUNTRIES
DEVELOPING COUNTRIES
ENERGY
LATIN AMERICA
MATHEMATICAL MODELS
SEPARATION PROCESSES
VARIATIONS
540110*