An Improved Atmospheric Component of Zebiak-Cane Model for Simulating ENSO Winds

The atmospheric component of the Zebiak-Cane (ZC) coupled model is a simple elegant framework that plays an instrumental role in the investigation of the fundamental coupled dynamics of the tropical ocean-atmosphere interaction and the El Nino/Southern Oscillation (ENSO) phenomenon. We attempt two simple thermal and dynamical modifications to reduce apparently spurious wind activities simulated by this atmospheric model in the eastern tropical Pacific under ENSO sea surface temperature (SST) anomaly forcing. First, motivated by established observational evidences, we manipulate the anomalous convective heating to be dependent on the sum of mean SST and SST anomalies and the low-level convergence. Second, we add an ad hoc parameterization for the effect of convective momentum transport (CMT) into the zonal momentum balance.