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ENSO phenomenon and 30–50 day variability in the Australian summer monsoon rainfall
Author(s) -
Suppiah Ramasamy
Publication year - 1993
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.3370130803
Subject(s) - climatology , el niño southern oscillation , monsoon , southern oscillation , environmental science , madden–julian oscillation , oceanography , geology , geography , meteorology , convection
The characteristics of 30–50 day variability in the Australian summer monsoon rainfall has been investigated by using station rainfall data. In particular, the influence of the El Niño/Southern Oscillation (ENSO) phenomenon on the Australian summer monsoon rainfall is analysed. Results of the power spectrum analysis indicate statistically significant peaks in the 30–50 day band during anti‐ENSO events in the north‐central, and north and east coast regions. The spectral analysis also reveals a statistically significant peak in this band during ENSO events in the inland desert and north and east coast regions. Filtered rainfall values show an eastward propagation pattern during anti‐ENSO events, whereas ENSO events demonstrate a pattern characteristic of a standing oscillation and sometimes a westward propagation pattern. The present study also suggests some tendency for the 30–50 day oscillation to be phase‐locked to the seasonal cycle of this region. The phase‐locking phenomenon is also observed in the daily mean sea‐level pressure at Darwin, which is very clear during the anti‐ENSO events.