The Impact of Convection on ENSO: From a Delayed Oscillator to a Series of Events

Abstract The NCAR Community Climate System Model, version 3 (CCSM3) exhibits persistent errors in its simulation of the El Niño–Southern Oscillation (ENSO) mode of coupled variability. The amplitude of the oscillation is too strong, the dominant 2-yr period too regular, and the width of the sea surface temperature response in the Pacific too narrow, with positive anomalies extending too far into the western Pacific. Two changes in the parameterization of deep convection result in a significant improvement to many aspects of the ENSO simulation. The inclusion of convective momentum transport (CMT) and a dilution approximation for the calculation of convective available potential energy (CAPE) are used in…

• NS
  National Science Foundation
• UD
  U.S. Department of Energy
• NA
  National Aeronautics and Space Administration
• OR
  Oak Ridge National Laboratory