Evaluation of rainfall drivers and teleconnections in an ACCESS AMIP run

Abstract

This study examines teleconnections from the El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), the Southern Annular Mode (SAM), and atmospheric blocking to rainfall over the Australian continent. The analysis is carried out for observations and an atmospheric GCM driven by prescribed time-varying sea surface temperatures. The model rainfall teleconnection to the blocking index is well captured in each season, whereas the IOD rainfall teleconnection is only weakly evident in the model. The ENSO rainfall response in eastern Australia is evident in spring in the model, but not winter. The small scale topographically-induced rainfall teleconnections from SAM are generally not captured in the model. In observations, ENSO and IOD are well correlated in spring, as are SAM and blocking. Only the first of these relationships between drivers is evident in the model. These mixed results indicate the need to improve representation of teleconnection processes.