An apparent relationship between Madden–Julian Oscillation and the advance of Indian summer monsoon

Abstract

A marked seasonality in the occurrence of Madden–Julian Oscillation (MJO) events is well known. The core region of oscillation is located at low latitudes (between the equator and 15°) in the summer hemisphere. The eastward progression of MJO signal interacts with the monsoon circulation and modulates the advance period of Indian summer monsoon (ISM). The analyses suggest that the mean advance period of ISM (41 days) is comparable with the life cycle of the MJO (30–60 days). The advance period of ISM has been categorised into normal, fast and slow‐advance years to decide the pace of the monsoon during progression of monsoon. During the period 1983–2015, the fastest progress of the monsoon was seen in the year 2013 (fastest advancement in the last 33 years) and slowest progress of monsoon was seen in the year 2002 (most lethargic advancement in the last 33 years). The results of the analyses show that variation in daily MJO‐amplitude during fast‐advancement years is more as compared with the normal and slow‐advancement years. The normal‐advancement years mostly occur during MJO phase 1 and phase 2 and fast‐advancement years frequently occur during MJO phase 2; however, slow‐advancement years are found to occur during MJO phase 5 and phase 6. The MJO phase 2 is the most frequent phase and MJO phase 8 is the least frequent phase during advance of monsoon. However, the highest amplitude is recorded during MJO phase 8. The strong (weak) monsoon current is modulated by strong (weak) MJO phases.

Orographic effect and multiscale interactions during an extreme rainfall event

“…Similar findings confirmed the contribution of ISO and quasi-biweekly oscillation components in facilitating the moisture supply during Chennai floods in 2015 (Krishnamurti et al 2017a). The 30-60 days oscillations linked to MJO have been deemed important for the Indian summer monsoon (ISM) and an intense MJO phase assists faster advancement of the ISM (Seetharam 2008, Singh et al 2017.…”

The Madden–Julian oscillation during the 2016 summer and its possible impact on rainfall in China

“…When the signals interact with the large-scale Asian monsoon circulation system, they exert a substantial influence on subseasonal rainfall variability over Asia (e.g. Lau et al, 1988;Lau and Waliser, 2012;Li, 2014;Mandapaka et al, 2017;Singh et al, 2017).…”

Modulation of active-break spell of Indian summer monsoon by Madden Julian Oscillation

“…Subsequently, as the MJO propagated eastwards, a gradual northward shift of the above normal rainfall band from south peninsula to north India was observed. Several studies have reported northward propagation of cloud bands over Indian monsoon region with MJO periodicity (Yasunari 1979;Sikka and Gadgil 1980;Gadgil 2003;Singh et al 2016). During phases 5 and 6, the above normal rainfall band was observed along monsoon trough region and active monsoon type rainfall distribution was observed.…”