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The impact of the Madden-Julian Oscillation on the formation of the Arabian Sea Monsoon Onset Vortex
  • Shreyas Dhavale,
  • Anantha Aiyyer
Shreyas Dhavale
North Carolina State University

Corresponding Author:sdhaval2@ncsu.edu

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Anantha Aiyyer
North Carolina State University
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During some years, a synoptic scale vortex called the Monsoon Onset Vortex (MOV) forms within the northward advancing zone of precipitating convection over the Arabian Sea. The MOV does not form each year and the reason is unclear. Since the Madden-Julian Oscillation (MJO) is known to modulate convection and tropical cyclones in the tropics, we examined its role in the formation of the MOV. While the convective and transition phases of the MJO do not always lead to MOV formation, the suppressed phase of the MJO hinders the formation of the MOV more consistently. This non-linear relationship between the MJO and MOV can be partially explained by the modulation of the large-scale environment, measured by a tropical cyclone genesis index. It also suggests that the Arabian Sea is generally near a critical state that is favorable for MOV formation during the monsoon onset period.
19 Apr 2023Submitted to ESS Open Archive
29 Apr 2023Published in ESS Open Archive
16 Sep 2023Published in Geophysical Research Letters volume 50 issue 17. 10.1029/2023GL104156