RMM

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

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 Hovmöllers 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.

Summary of all modes
Original: The original Wheeler-Hendon (2004) methodology of subtracting the 120-day running mean	Total	Components by Variable
Total: As above, but retaining the interannual (120-day) signal	Total	Components by Variable
MJO: MJO-filtered OLR, U-850, and U-200 projected onto the original Wheeler-Hendon EOFs	Total	Components by Variable
Low: Lowpss-filtered (&gt 120 days) OLR, U-850, and U-200 projected onto the original Wheeler-Hendon EOFs	Total	Components by Variable
ER: OLR, U-850, and U-200 filtered for Equatorial Rossby (ER) waves and projected onto the original Wheeler-Hendon EOFs	Total	Components by Variable
Kelvin: OLR, U-850, and U-200 filtered for Kelvin waves and projected onto the original Wheeler-Hendon EOFs	Total	Components by Variable

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
Hovmöller with 120-day mean removed	40 days	90 days
Hovmöller of 120-day running mean	90 days	180 days