MJO (Madden Julian Oscillation)
The links and descriptions are below as well as links to some other MJO timeseries created at other institutions.
A description of the timeseries format is available. NOTE: OMI has been updated through August 28, 2017. These PCs will differ slightly from the previous version since the sample used for the 20-96 day filter is longer (1979-2017), resulting in slightly different values for the filtered OLR. The EOFs used are still from 1979-2012 (see below). The previous (1979-2012) version of OMI can be obtained here. NOTE: When comparing OMI directly with RMM, to obtain the proper phase the sign of OMI PC1 and the PC ordering should be reversed, so that OMI(PC2) is analogous to RMM(PC1) and -OMI(PC1) is analogous to RMM (PC2).
Daily MJO index time series from 1979.
The OLR MJO Index
|Projection of 20-96 day filtered OLR, including all eastward and westward wave numbers onto the daily spatial EOF patterns of 30-96 day eastward filtered OLR.||OMI values|
The Original OLR MJO Index
|Projection of 30-96 day eastward only filtered OLR onto the spatial EOF patterns of 30-96 day eastward filtered OLR. This results in a smoother index than OMI due to more restrictive filtering.||OOMI values|
The Real-time OLR MJO Index
|Projection of 9 day running average OLR anomalies onto the daily spatial EOF patterns of 30-96 day eastward filtered OLR. OLR anomalies are calculated by first subtracting the previous 40 day mean OLR. The running average is tapered as the target date is approached.||ROMI values|
The Filtered OLR MJO index.
|Univariate EOF of normalized 20-96 day filtered OLR averaged from 15S-15N, by longitude. The same spatial EOF pattern is used for the entire year (see below).||FMO values|
The Velocity Potential MJO index.
|Calculated in the same way as the Wheeler-Hendon RMM, except using 200 hPa Velocity Potential instead of OLR, along with U200 and U850 in a combined EOF (see link to Ventrice et al. 2013 below).||VPM values|
Kiladis G.N., J. Dias, K.H. Straub, M.C Wheeler, S.N. Tulich, K. Kikuchi, K.M. Weickmann, M.J. Ventrice. A comparison of OLR and circulation based indices for tracking the MJO. Monthly Weather Review, May 2014, 142 1697-1715.For the VPM, please cite:
Ventrice et al. A Modified Multivariate Madden-Julian Oscillation Index Using Velocity Potential. Monthly Weather Review, December 2013, 141, p. 4197-4120.
Composite streamfunction and OLR patterns for RMM and OMI based on the events that exceed 1 standard deviation for each phase of the PC combination.These are based on data from 1979 through 2012, and the number of events in each composite is given as "N= " at the bottom of each plot. Blue shading denotes negative OLR anomalies (regions of convection) and red positive (suppressed), with two levels of shading at +- 10 and +- 6 W/m**2. Streamfunction contour interval is 5 X 10**5 m**2/s at 200 hPa, and 2 X 10**5 m**2/s at 850 hPa. To facilitate comparison with RMM, these composites are constructed by reversing the sign of OMI PC1 and the OMI PC ordering, so that OMI(PC2) is analogous to RMM(PC1) and -OMI(PC1) is analogous to RMM(PC2), as described in Kiladis et al. 2014.
- 200mb OMI DJF
- 200mb OMI JJA
- 200mb RMM DJF
- 200mb RMM JJA
- 850mb OMI DJF
- 850mb OMI JJA
- 850mb RMM DJF
- 850mb RMM JJA
MJO EOF Patterns
OMI EOF patterns.
- The ASCII EOF values are available via ftp for EOF1 and EOF2 . They can be read using the code read.eof.f. User can retrieve the files via the web or using an (anonymous) ftp client at the address ftp.cdc.noaa.gov. Then, cd to /Datasets.other/MJO/.
OMI EOF Animations
- An animation of the daily OMI EOF's (realtime player format).
VPM EOF patterns.
- The VPM EOFs are computed using zonal wind and velocity potential based on NCEP reanalysis version 1 from 1979 to 2012.
FMO EOF patterns.
- The ASCII FMO EOF values are available from here.
FMO Spatial EOFs
Other MJO indices and MJO information.
- The All-season Real-time Multivariate (RMM) MJO Index (Wheeler-Hendon) from the The Centre for Australian Weather and Climate Research.
- Bimodal ISO Index for historical data analysis and real time monitoring from the International Pacific Research Center.
- The NOAA/CPC MJO page: Contains monitoring maps and plots, data and forecasts.
- Adrian Matthews MJO page: A very complete page with MJO description, current research topics, illustrations and animations from Adrian Matthews at the University of East Anglia.
- Carl Schreck's analysis of the RMM components.
- A MJO tutorial from the University of Wyoming.