The Combined Influence of the Madden-Julian Oscillation and El Niño-Southern Oscillation on Australian Rainfall
Presentation
Paper/Presentation Title | The Combined Influence of the Madden-Julian Oscillation and El Niño-Southern Oscillation on Australian Rainfall |
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Presentation Type | Presentation |
Authors | Cowan, Tim, Wheeler, Matthew C. and Marshall, Andrew |
Year | 2022 |
Conference/Event | 19th Annual Meeting of the Asia Oceania Geosciences Society (AOGS 2022) Conference |
Event Details | 19th Annual Meeting of the Asia Oceania Geosciences Society (AOGS 2022) Conference AOGS 2022 Delivery In person Event Date 01 to end of 05 Aug 2022 Event Location Singapore Event Web Address (URL) |
Abstract | The statistical relationship between climate and weather variability modes and Australian rainfall has been an ongoing research question since the early 1980s. Nowadays, the tropical weather monitoring is a key service offered by the Australian Bureau of Meteorology (BoM), complementing the multi-week to seasonal prediction service. Modes like the Madden Julian Oscillation (MJO) are tracked and displayed each day on the BoM's tropical monitoring web page alongside maps displaying the MJO-related weekly rainfall probabilities and wind anomalies across Australia for each season. Motivated by the need for a contemporary understanding, we re-examine the MJO's impact on Australian rainfall, and then investigate the joint role of ENSO and the MJO on rainfall, with particular focus on the austral summer monsoon season. Using updated observations (1974-2021), we find that the strong impact of MJO Phases 5 and 6 on northern Australia's summer rainfall has weakened by around 5% over the tropical central north. Over southeast Australia, there has also been a weakening in the suppressed rainfall teleconnection in MJO Phases 2 and 3 in austral spring. During the El Niño years, the dry MJO Phases 8, 1 and 2 are associated with a reduction in summer rainfall probabilities to below 30% in the far north, yet the chances of increased rainfall in wet MJO Phases 5 and 6 remain much the same as for all years. In contrast, the impact of La Niña on the MJO phase composites is less pronounced, with only marginally increased summer rainfall probabilities across much of Australia in most MJO phases. The largest contrast between El Niño and La Niña conditions occurs in spring over northern and eastern Australia. The updated composite maps and statistics will become an important resource for estimating the influence of the MJO and ENSO on regional rainfall variations at intraseasonal timescales. |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 370105. Atmospheric dynamics |
370202. Climatology | |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Centre for Applied Climate Sciences (Research) |
Australian Bureau of Meteorology |
https://research.usq.edu.au/item/zyz33/the-combined-influence-of-the-madden-julian-oscillation-and-el-ni-o-southern-oscillation-on-australian-rainfall
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