On the linkage between extreme rainfall and the Madden–Julian Oscillation over the Indian region

Abstract

The relationship between extreme rainfall events (ERE) and the Madden-Julian Oscillation (MJO) over the Indian Subcontinent is intriguing. In this regard, the study investigates in detail the association between the ERE and the MJO. Daily Tropical Rainfall Measuring Mission (TRMM) data were used for the period 1998-2015. The real-time multivariate MJO index was applied to classify active and suppressed phases of the MJO. The percentile-based threshold indices, change in probability, logistic regression models and composite analysis were used to understand the statistical and atmospheric circulation features. The results suggest that the frequency and rainfall contribution of the ERE were found to be higher during the active phases of the MJO across the seasons over the geographically distinct regions. The profound influence of the MJO on the ERE was found during the post-monsoon over the southern Indian peninsula and Bay of Bengal regions. During the Indian Summer Monsoon (ISM), the prominent signals of the MJO are limited to the south of 20 N. The logistic regression and cumulative probability changes affirm the above results. The composite analysis of various diagnostic parameters reveals the background synoptic conditions during the post-monsoon and the propagation of the Rossby convective lobe during the ISM might facilitate the occurrences of the ERE during the active phases of the MJO. The study highlights the space-time evolution of the ERE and the relative influence of the MJO across the seasons.Besides, its insights have practical implications for the understanding and prediction of sub-seasonal rainfall extremes over the Indian Subcontinent.

The Anomalous Weather Parameters that Lead to the Extreme Rainfall of Kerala in August 2018

“…3 Madden Julian Oscillation (MJO) is one factor that affects the intraseasonal variability of the monsoon. During the active phase of MJO, precipitation intensity can increase considerably (Roxy et al 2019;Peng et al 2019;Anandh and Vissa 2020). Wind speed anomalies, cloudiness and precipitation analyses elucidate the presence of an active phase of MJO.…”

Intraseasonal variability of sea level in the Western North Pacific

“…After the Maritime Continent, it starts weakening but continues to travel eastward before finally dissipating in the Western Hemisphere. MJO is associated with planetary-scale convections, which could have a strong impact on extreme rainfall in the tropics (e.g., Anandh & Vissa, 2020;Xavier et al, 2014). In boreal summer (June-August), the Boreal Summer Intraseasonal Oscillation (BSISO) is the prevailing ISO mode in the tropics (J.-Y.…”

“…The ISO of the atmosphere can significantly influence the ocean. Due to the strong modulations on heavy rainfall (e.g., Anandh & Vissa, 2020;P. Ren et al, 2018;Xavier et al, 2014) and tropical cyclones (e.g., Hall et al, 2001;Maloney & Hartmann, 2000a, 2000b, the atmospheric ISO can reduce the sea surface temperature after a few days of lag (e.g., Feng, Haines, & de Boisséson, 2018;Feng, Haines, Liu, et al, 2018;Roxy & Tanimoto, 2012;Shinoda et al, 1998;Woolnough et al, 2000).…”

Role of synoptic-scale circulations, mechanisms, and precursors during extreme rainfall events over the Southern Indian Peninsula

“…The intricate interactions among the synoptic-scale monsoon circulations, oscillating monsoon trough, propagating intraseasonal oscillations (ISO), atmospheric rivers, and tropical (extratropical) teleconnections play a crucial role in the occurrences of ERE Responsible Editor: J.-F. Miao. (Francis and Gadgil, 2006;Romatschke et al 2010;Roxy et al 2017;Murata et al 2017;Hunt et al 2018;Viswanadhapalli et al 2019;Anandh and Vissa 2020). The manifestations of synoptic drivers in the occurrences of ERE are not only limited to ISM, but also other seasons as well.…”