Distinct growth rates of the two ENSO types

El Niño-Southern Oscillation (ENSO) events can be grouped into two types based on their sea surface temperature anomaly (SSTA) spatial patterns , i.e., eastern-Pacific ( EP ) and central-Pacific (CP) types. In this study, we propose a new method to empirically diagnose linear growth rates of the EP and CP ENSO types due to a limitation of applying the traditional Bjerknes stability (BJ) index method simply to these two types. We spatially project the peak-time symmetric component of the mixed-layer oceanic heat budget terms onto the ENSO-related SSTA patterns to estimate the ENSO grow rate. After validating the method by comparing it with the BJ index , we show that the growth rate is positive for the CP ENSO type and weakly negative for the EP ENSO type, contributed by different feedback terms. The CMIP5-based multi-model ensemble mean shows similar characteristics as the reanalysis for the EP ENSO type rather than CP ENSO type.