The Vertical Structures of Atmospheric Temperature Anomalies Associated with Two Flavors of El Niño Simulated by AMIP II Models

Recent studies have identified different modes associated with two flavors of El Nino in terms of the three-dimensional structure of atmospheric temperature. The first is a deep-warm mode, which features a coherent zonal mean warming throughout the troposphere from 30°N to 30°S with cooling aloft. The second is a shallow-warm mode, which features strong wave signatures in the troposphere with warmth (coolness) over the central Pacific (western Pacific). The ability to simulate these two modes is a useful metric for evaluating climate models. To understand the reproducibility of these two modes, the authors analyzed the multimodel ensemble mean (MMEM) of 11 atmospheric general circulation models (AGCMs) that participated in the second phase of the Atmospheric Model Intercomparison Project (AMIP II). Each model was run in an AGCM-alone mode forced by historical sea surface temperatures covering the period 1980–99. The authors find that atmospheric temperature variability is generally well captured ...