Abstract
Abstract. The timing of the first monsoon burst of the season, or the monsoon onset, can be a critical piece of information for agriculture, fire management, water management, and emergency response in monsoon regions. Why do some monsoon seasons start earlier or later than others? Previous research has investigated the impact of climate influences such as the El Niño–Southern Oscillation (ENSO) on monsoon variability, but most studies have considered only the impact on rainfall and not the timing of the onset. While this question could be applied to any monsoon system, this research presented in this paper has focused on the Australian monsoon. Even with the wealth of research available on the variability of the Australian monsoon season, the timing of the monsoon onset is one aspect of seasonal variability that still lacks skilful seasonal prediction. To help us better understand the influence of large-scale climate drivers on monsoon onset timing, we recreated 11 previously published Australian monsoon onset datasets and extended these to all cover the same period from the 1950/1951 through the 2020/2021 Australian wet seasons. The extended datasets were then tested for correlations with several standard climate indices to identify which climate drivers could be used as predictors for monsoon onset timing. The results show that many of the relationships between monsoon onset dates and ENSO that were previously published are not as strong when considering the extended datasets. Only a strong La Niña pattern usually has an impact on monsoon onset timing, while ENSO-neutral and El Niño patterns lacked a similar relationship. Detrended Indian Ocean Dipole (IOD) data showed a weak relationship with monsoon onset dates, but when the trend in the IOD data is retained, the relationship with onset dates diminishes. Other patterns of climate variability showed little relationship with Australian monsoon onset dates. Since ENSO is a tropical climate process with global impacts, it is prudent to further re-examine its influences in other monsoon regions too, with the aim to evaluate and improve previously established prediction methodologies.
Highlights
The livelihood of about 50 % to 60 % of the world’s population is impacted by the global monsoon system (e.g. Qiao et al, 2012; Wang and Ding, 2008; Yancheva et al, 2007)
Kajikawa et al (2010) reported a correlation coefficient between the SON Southern Oscillation Index (SOI) and Australian monsoon onset of −0.48, while Holland (1986) showed no significant correlation between seasonal monsoon onset and the SOI prior to the summer monsoon season. Do these correlations remain robust when more decades of data are considered? How can the relationships between monsoon onset and climate influences from different onset criteria accurately be compared when each respective dataset covers different time periods? the aim of this study is to further investigate how much seasonalscale climate drivers influence the timing of the Australian monsoon onset based on various onset criteria over the same time period
While this study focuses on the Australian monsoon, from a global perspective an understanding of the dynamical monsoon onset is important because tropical cyclones are more likely to form along the monsoon trough (Choi and Kim, 2020; Davidson et al, 1989; Mcbride, 1983; Wheeler and McBride, 2011); and monsoon bursts, whether they include a tropical cyclone or not, can have serious impacts on public health and safety (Martinez et al, 2020), transport and aviation (Pramono et al, 2020), flooding and ecological effects (Crook et al, 2020), and the local economy (Jain et al, 2015)
Summary
The livelihood of about 50 % to 60 % of the world’s population is impacted by the global monsoon system (e.g. Qiao et al, 2012; Wang and Ding, 2008; Yancheva et al, 2007). With all regional monsoon systems, the seasonal monsoon onset, or the first burst of monsoon rains of the season, is a much-anticipated event with documented temporal variability (Ali et al, 2020; Fitzpatrick et al, 2015; Lisonbee et al, 2020; Parija, 2018; Pradhan et al, 2017). This variability may be driven by larger-scale climate variability, such as the El Niño–Southern Oscillation (ENSO). Correlations between ENSO and the monsoon onset have been reported for the South Asian and East Asian monsoons (Wang et al, 2008b; Zhou and Chan, 2007), the Indian monsoon (Misra et al, 2018; Misra and Bhardwaj, 2019; Noska and Misra, 2016), the African and southern African monsoons (Semazzi et al, 2015), the South American monsoon (Grimm et al, 2015), the Mexican and southwest US monsoon (Gochis, 2015), and the Australian monsoon
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
