Indian Ocean Variability in the CMIP5 Multimodel Ensemble: The Basin Mode

• DOI: 10.1175/jcli-d-12-00678.1
• Publication Date: 2013-03-21T19:38:03Z
• Authors: Yan Du; Shang-Ping Xie; Ya-Li Yang; Xiao-Tong Zheng; Lin Liu; Gang Huang
• Keywords: Downwelling; Anticyclone; Madden–Julian oscillation; Kelvin wave; Anomaly (physics)

Abstract This study evaluates the simulation of Indian Ocean Basin (IOB) mode and relevant physical processes in models from phase 5 Coupled Model Intercomparison Project (CMIP5). Historical runs 20 CMIP5 are available for analysis. They reproduce IOB its close relationship to El Niño–Southern Oscillation (ENSO). Half capture key processes: a downwelling oceanic Rossby wave southern tropical (TIO) precedes development boreal fall triggers an antisymmetric wind anomaly pattern across equator following spring. The anomalous induces second warming north (NIO) through summer sustains anticyclonic anomalies northwest Pacific by radiating warm tropospheric Kelvin wave. NIO is indicative ocean–atmosphere interaction interior TIO. More than half display double peak warming, as observed Niño, while rest show only one winter peak. intermodel diversity characteristics seems related thermocline adjustment south TIO ENSO-induced variations. Almost all multidecadal variations variance, possibly modulated ENSO.