DISCLAIMER: Please note these pages present experimental analyses developed by researchers at CICS-NC and/or of interest to the CICS-NC community and their collaborators. These analyses are subject to change as our understanding of the Earth's climate system improves and/or our interests change. There is no guarantee on their future availability.

NCSU > CICS-NC > Monitoring > MJO > RMM

CICS-NC: RMM (Real-time Multivariate MJO) Index

Updated: 19 Apr, 2014

Wheeler and Hendon (2004) constructed the RMM index for monitoring the MJO. This index consists of the first two principal components (PCs) of OLR, 850-hPa zonal wind, and 200-hPa zonal wind averaged 15S-15N.

This page takes that simple index and breaks it down into its components, either by variable, longitude, or latitude. In each case, the original RMM emperical orthogonal functions (EOFs) are used, but only a subset of the data is projected onto them. All of these plots are re-standardized based on their 1980-2010 time series. This step is necessary for comparison because the OLR PCs, for example, have significantly lower amplitudes.

The Hovmollers show longitude-time plots for OLR, U-850, and U-200. The shading indicates the observed anomalies, while the contours are the projection of those anomalies onto the RMM EOFs.

Total RMM 40 days 90 days
RMM by variable 40 days 90 days
RMM by latitude 40 days 90 days
RMM by longitude 40 days 90 days
RMM of 120-day running average 120 days 240 days
Hovmoller with 120-day
mean removed
40 days 90 days
Hovmoller of 120-day
running mean
90 days 180 days