Unstable Coupled Atmosphere–Ocean Basin Modes in the Presence of a Spatially Varying Basic State

The Role of Zonal Advection Feedback in Phase Transition and Growth of ENSO in the Cane-Zebiak Model

“…It implies that the two advective thermal effects act to favor the transition and growth of ENSO. They have been considered as the important terms in the ENSO phase transition and growth in the theoretical studies (e.g., Hirst, 1986Hirst, , 1988Wakata and Sarachik, 1991;Kang and An, 1998). The SST tendencies due to the vertical thermal advection by anomalous upwelling (Fig.…”

“…edited by Rothstein et al, 1998). A great deal of work has been done regarding the mechanism of the growth and phase transition of the ENSO (e.g., Wyrtki, 1985;Yamagata, 1985;Hirst, 1986Hirst, , 1988Suarez and Schopf, 1988;Battisti and Hirst, 1989;Wakata and Sarachik, 1991;Jin and Neelin, 1993;Jin, 1996Jin, , 1997aLi,1997;An and Kang, 1998;Wang et al, 1999;Jin and An, 1999).…”

Effects of the Meridional Extent of Mean Equatorial Upwelling on Atmosphere-Ocean Coupled Instabilities over an Unbounded Ocean

“…In this work, we will extend the work of Hirst (1985Hirst ( , 1986 by considering coupled instabilities on an unbounded equatorial beta plane in the presence of mean upwelling of finite meridional extent in the SST equation. This will provide an interpretation of some previous work Wakata and Sarachik (1991b), henceforth denoted WS, on the coupled atmosphere-ocean instabilities in a bounded basin with the size of the Pacific in the presence of both zonal inhomogeneities (thermocline tilt) and meridional inhomogeneities (upwelling extent) in the basic state. The interaction between the atmosphere and the ocean is introduced as follows.…”

“…As far as we know, no clear evidence of eastward propagating SST anomalies during ENSO has been seen in the observations. These differences in propagation characteristics were investigated by Wakata and Sarachik (1991b). They investigated the atmosphere-ocean coupled instability on an equatorial beta plane, where the ocean is bounded by walls at the east and west and the atmosphere is assumed periodic around the earth.…”

Contrasting the eastern Pacific El Niño and the central Pacific El Niño: process-based feedback attribution

“…We wish to add that the analysis of partial SST anomalies based on (4) and (7) is complementary to the heat budget analysis based on the SST equation (e.g., Hirst 1986;Wakata and Sarachik 1991;Kang et al 2001;Kug et al 2009). The term �T (ocean) corresponds to the sum of the SST anomaly due to the ocean heat storage term and the convergence of energy transport by oceanic motions (e.g., anomalous vertical, zonal and meridional advections).…”