On the role of oceanic entrainment temperature ( T e ) in decadal changes of El Niño/Southern Oscillation

摘要: Abstract. The role of decadal changes in ocean thermal structure modulating El Nino/Southern Oscillation (ENSO) properties was examined using a hybrid coupled model (HCM), consisting statistical atmospheric and an oceanic general circulation (OGCM) with explicitly embedded empirical parameterization for the temperature subsurface water entrained into mixed layer (Te), which constructed via EOF analysis model-based historical data. Using Te models from two subperiods, 1963–1979 (Te63−79) 1980–1996 (Te80−96), system exhibits striking different interannual variability, including oscillation periods propagation characteristic sea surface anomalies (SSTAs) along equator. In Te63−79 run, features 2–3 yr westward SSTAs equator, while Te80−96 it is characterized by 4–5 eastward propagation. Furthermore, Lag Covariance Analysis (LCOA) utilized to illustrate leading physical processes responsible change SST. It shown that acts modulate relative strength zonal advective thermocline feedbacks system, ENSO properties. Two additional sensitive experiments were conducted further respective roles mean states behaviors. These simulated are consistent observed shift occurred late 1970s previous simulation performed intermediate (ICM) described Zhang Busalacchi (2005), indicating dominant plays changes.