MJO: Madden-Julian Oscillation Diagnostics
"The Madden–Julian oscillation (MJO) is the largest element of the intraseasonal (30–90 days) variability in the tropical atmosphere. It is a large-scale coupling between atmospheric circulation and tropical deep convection.[1][2] Rather than being a standing pattern (like ENSO) it is a traveling pattern, propagating eastwards at approximately 4 to 8 m/s, through the atmosphere above the warm parts of the Indian and Pacific oceans. This overall circulation pattern manifests itself in various ways, most clearly as anomalous rainfall." (Wikipedia)
The US-CLIVAR MJO working group has developed diagnostics for objectively evaluating the MJO. Two WWW sites demonstrate the diagnostics: http://www.ncl.ucar.edu/Applications/mjoclivar.shtml and http://climate.snu.ac.kr/mjo_diagnostics/index.htm. Operational centers monitor the MJO and indicies are available at: http://cawcr.gov.au/staff/mwheeler/maproom/RMM/ and http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_mjo_index/mjo_...
Key Figures
Hovmuller diagram (time vs longitude) for an active MJO two-year period (1996-1997). (Climate Data Guide; D. Shea)
MJO phase diagram for period 10/16/1996 to 4/15/1997. (Climate Data Guide; D. Shea)
Composite life cycle of 20-100 day band passed filtered anomaly OLR, U850, V850 for the years 1995-1999. The phase (eg P3, means "Phase 3") and the number of days used to create the composite are at the lower right. (Climate Data Guide; D. Shea)
Climatological cross correlations spanning the period Oct 1996 - Dec 2005 using 20-100 band pass filtered data. The reference time series is the central Indian Ocean regional precipitation time series. This is correlated with precipitation and zonal wind anomalies. (Climate Data Guide; D. Shea)