Understanding Long-Term Variability of the Madden-Julian Oscillation Leveraging in-Situ Observations

Many studies have suggested that the Madden-Julian Oscillation (MJO) is a main source of
subseasonal-to-seasonal (S2S) predictability and that its amplitude has been increasing over
the last few decades. Potential long-term variability of the MJO is an important topic of
research because changes in MJO propagation and amplitude characteristics could alter its role as a source of S2S predictability. Understanding long-term variability of the Madden-Julian Oscillation is challenging because characterizing its behavior outside of the satellite era lacks detailed information about its observed state, and relies on general circulation models’ typically poor MJO representation. In this presentation, we discuss the contrast between long-
term variability of the MJO from 1942 to present derived from global reanalysis products with the MJO behavior inferred from tropical in-situ observations during the same period.