The origin of the intermodel diversity of the El Niño–Southern Oscillation (ENSO) variability is investigated by applying a singular value decomposition (SVD) analysis between the intermodel tropical Pacific sea surface temperature anomalies (SSTA) variance and the intermodel ENSO stability index (BJ index). The first SVD mode features an ENSO-like pattern for the intermodel SSTA variance (74% of total variance) and the dominant thermocline feedback (TH) for the BJ index (51%). Intermodel TH is mainly modified by the intermodel sensitivity of the zonal thermocline gradient response to zonal winds over the equatorial Pacific (βh), and the intermodel βh is correlated higher with the intermodel off-equatorial wind stress curl anomalies than the equatorial zonal wind stress anomalies. Finally, the intermodel off-equatorial wind stress curl is associated with the meridional shape and intensity of ENSO-related wind patterns, which may cause a model-to-model difference in ENSO variability by influencing the off-equatorial oceanic Rossby wave response.
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2014 R1A2A1A11049497). The authors appreciate all data providers, which can be found at the following web addresses: ERSSTv3b at http://www.esrl.noaa.gov/psd/data/gridded/data.noaa.ersst.html, SODAv2.2.4 at http://sodaserver.tamu.edu/assim/SODA_2.2.4/, and CMIP5 at http://www-pcmdi.llnl.gov/.
All Science Journal Classification (ASJC) codes
- Earth and Planetary Sciences(all)