Model Diagnosis of El Niño Teleconnections to the Global Atmosphere-Ocean System
Prof. Lau Ngar-Cheung (劉雅章教授)
Chinese University of Hong Kong
The essential El Niño-Southern Oscillation (ENSO) signals originate from the tropical Pacific (TP). However, the impacts of ENSO are felt in many other parts of the globe. Major ENSO events are accompanied by notable changes in the extratropical atmospheric circulation in both hemispheres, various monsoon systems located beyond the TP, global air temperature and precipitation patterns, and the sea surface temperature (SST) distribution throughout the World Oceans. During the past several decades, this investigator has participated in a sustained effort to study the processes contributing to these ‘teleconnections’ between ENSO forcing in TP and variations in the atmosphere-ocean system elsewhere. These diagnoses are based on a large suite of experiments with several generations of general circulation models (GCMs) at the Geophysical Fluid Dynamics Laboratory (GFDL). These experiments are specifically designed to reveal various facets of the teleconnections with ENSO. In this presentation, a summary is offered of the principal findings of this series of model studies. An account is given of the train of thought underpinning this sequence of experiments, so as to illustrate how certain experimental setups have been motivated by the problem or hypothesis at hand.