Seasonal cycle of the Mindanao Dome in the CCSR/NIES/FRCGC atmosphere-ocean coupled model

Abstract

Using atmosphere-ocean coupled general circulation models (CGCMs) with different resolution, we investigate the dependency on horizontal resolution to reproduce the seasonal variation of the Mindanao Dome (MD). The seasonal cycle of the MD is successfully simulated in the high resolution CGCM. It is generated by local Ekman upwelling and destroyed by westward warm anomaly propagation during late spring. The warm anomaly is caused by Ekman downwelling induced by westward wind stress and negative wind stress curl anomaly associated with southward shift of the inter-tropical convergence zone in the central tropical Pacific. However, in the lower resolution model, the seasonal cycle is not represented owing to the insufficient wind forcing. The higher resolution atmospheric model improves the wind forcing in the CGCM, but it doesn't go far enough. The reproduction of the wind forcing depends not only horizontal resolution of an atmospheric model but also on that of an ocean model. Copyright 2005 by the American Geophysical Union.