Lesley L. Smith – Madden-Julian Oscillation

All plots preliminary.        

The main PSL MJO webpage is here.

Generally, the transformation from PCs to MJO phase and strength is the same as the transformation from 2-D Cartesian coordinates to 2-D Spherical-Polar coordinates

OLR-based MJO index "mjoindices" from https://github.com/cghoffmann/mjoindices

Comparison of mjoindices 1979-2018 calculation and 1940-2023 calculation

Comparison of ERA-5 OLR version with original version of MJO Indices (1979-2018)
where original method is described in "A Comparison of OLR and Circulation-Based Indices for Tracking the MJO"
G.N. Kiladis, et al., Mon. Wea. Rev., 142, pp 1697-1715, May 2014.

For day-of-year 23:

For all days-of-year:

For sample year 2011:

For day-of-year 50: