Tripling of MJO residence time over the rapidly warming Indian Ocean during summer monsoon.

The Madden-Julian Oscillation (MJO) is the dominant mode of intraseasonal tropical atmospheric variability with far-reaching influences on global weather systems. During boreal winter, the MJO typically exhibits regular eastward propagation, whereas in summer, it displays more complex propagation characteristics, such as frequent stalling over the Indian Ocean. Here we show a threefold increase in the MJO residence time over the Indian Ocean during the Asian summer monsoon in recent four decades.