AchutaRao, Krishna, Kenneth R. Sperber, and the CMIP Modelling Groups
The El Nino Southern Oscillation (ENSO) simulations of 17 global coupled ocean-atmosphere general circulation models (CGCMs) from the Coupled Model Intercomparison Project (CMIP) are analyzed. Monthly mean values of surface air temperature, sea level pressure and precipitation for 80 years are analyzed from control runs. Nearly half of the models studied do not employ any form of flux correction, although flux-corrected CGCMs were better at simulating the base state of the temperature field in the equatorial Pacific but not necessarily better at simulating ENSO variability. While a subset of the models produce realistic amplitudes of NINO3 and the Southern Oscillation Index (SOI), ENSO often tends to occur at a higher than observed frequency. A few models also capture the teleconnection between NINO3 temperature anomalies, SOI, and the global surface air temperature, sea level pressure and precipitation. Composities of ENSO warm and cold events demonstrate that only a few models simulate phase locking of ENSO with the seasonal cycle. Most models have problems in simulating the ENSO related sea level pressure variations over the eastern Pacific, and this is associated with errors in the precipitation response. [pdf file (revised)]
UCRL-MI-123395