The MJO anomalies have the following characteristics:

1. Gaussian about the equator

2. Sinusoidal in x, with phase advancing eastward

3. The eastern edge of the MJO envelope can either be coupled to the SST or uncoupled.

If coupled, the eastern edge is a specified isotherm (usually 28°C)

As the isotherm moves, the east edge of the MJO moves with it. (258)

If uncoupled, the edge is a specified longitude that remains fixed. (262)

In either case:

A 20° longitude wide ramp tapers the sinusoid at the eastern edge.

East of the edge isotherm, forcing remains climatological

The imposed anomalies affect the model ocean in three ways:

1. The stress works on the ocean dynamics

2. The windspeed affects the latent heat fluxes and vertical mixing

3. Clouds affect the short-wave radiation.

Experiments consist of varying the strength of stress, windspeed and clouds, either singly or in combination.

All the plots show results from years 4 and 5 of the model (days 1080-1800). Model spinup is 3 years, then the anomalies are imposed, so at day 1080 all the runs are identical.

- Mean SST difference (x,y) with MJOs (coupled)
- Mean SST difference (x,y) with MJOs (uncoupled)
- Mean surface zonal current difference (x,y) with MJOs (coupled)
- Mean surface zonal current difference (x,y) with MJOs (uncoupled)
- Mean surface meridional current difference (x,y) with MJOs (uncoupled)
- Mean surface vector current difference (x,y) with MJOs (uncoupled)
- Mean w and u,v vectors in the surface layer due to MJOs (uncoupled)
- Mean zonal current difference on the equator (x,z) with MJOs (uncoupled)
- Mean meridional plane circulation difference at 145°E-165°E (y,z) with MJOs (uncoupled)
- SST difference on the equator (uncoupled MJOs) (smooth 25 days)
- SST difference on the equator (stress only) (smooth 95 days)
- Zonal current difference on the equator (stress only) (smooth 25 days)
- Zonal current difference on the equator (stress only) (smooth 95 days)
- SST and zonal current difference on the equator (stress+speed). Detail of west-central Pacific)
- SST and zonal current difference on the equator (stress+speed) (smooth 95-day triangle). Detail of west-central Pacific
- SST and zonal current difference on the equator (stress+speed)(smoothed and unsmoothed)
- Longitude of SST=28°C on the equator (stress only) (smooth 35 days)
- Mean SST, sea level, U difference on the equator due to (uncoupled) MJOs
- Mean temperature and zonal current difference on the equator due to CMJOs (x,z)
- dSST/dt difference on the equator due to CMJOs
- Heat balance terms difference on the equator due to CMJOs
- Upward advection of eastward momentum on the equator due to CMJOs
- Mean advective zonal momentum terms in the surface layer due to MJOs
- Mean advective SST terms due to MJOs
The effect of allowing the MJO windspeed to influence the vertical mixing and evaporation. In this model, evaporation is a function of windspeed and SST (through a simplified bulk formula), while vertical mixing is a (complicated) function of windspeed, mixed layer depth, dT/dz and shear.

- The windspeed at 0°, 155°E with and without MJOs
- SST along the equator with and without MJO windspeed
- SST at 0°, 155°E with and without MJO windspeed
- Time series of evaporation at 0°, 155°E with and without MJO windspeed
- Time series of evaporation and vertical mixing difference at 0°, 155°E-165°E due to MJO windspeed
- Time series of evaporation, vertical mixing and vertical advection at 0°, 150°E-170°E compare different runs
- Time series of combined evaporation, vertical mixing and vertical advection at 0°, 150°E-170°E compare different runs
- Time series of SST and differences at 150°E-170°E compare different runs: 2°S, Eq, 2°N, Another version at Eq
- Time series of heat flux terms at 150°E-170°E compare different runs: Eq, 2°S, 1°S, 1°N, 2°N
- Time series of advective heat flux terms at 150°E-170°E due to MJOs. Compare different runs: Stress+speed. Stress only
- Mean evaporation and vertical mixing difference due to MJO windspeed
- Mean evaporation, vertical mixing and vertical advection difference due to MJO winds: Stress+speed, Stress only, Stress+speed, Include zonal adv too, Stress+speed, zonal adv but no Vmix
- Time series of evaporation at the equator with and without MJO windspeed
- Time series of the zonal SST gradient at the equator with and without MJO windspeed
- Time series of zonal SST advection at the equator, 170°E-180° due to MJO windspeed
- Mean SST differences (x,y) due to MJOs: Including windspeed.
Difference with and without windspeed. Combined plot
- Temperature as a function of true z and time (Eq, 150°E-170°E) (Climatology, MJOs, Difference). For stress-only run (262)
- Zonal current as a function of true z and time (Eq, 150°E-170°E) (Climatology, MJOs, Difference)
- Zonal wind and pressure gradient difference (MJO-climatological run) (Eq, 150°E-170°E)
- Timing of features related to upwelling (MJO run 267)
- Timing of features related to upwelling (with dT/dz) (MJO run 267)
- Timing of features related to upwelling (with dT/dz) (MJO run 267) (nicer labels)
- Timing of features related to upwelling (MJO run difference from climatology 267-255)
- Momentum balance terms (Tau-x, dP/dx, U1, U6) (MJO run difference from climatology 267-255)
- Mean heat flux terms (mean difference compared to 255 over days 60-180): 282 - 4 N/m2 winds 285 - 3 N/m2 winds 286 - 4 N/m2 winds and clouds
- Check heat flux terms in a run with cloud oscillations, too (286): SST Solar and vertical advection terms Solar and Vertical advection differences SST and integrated heat fluxes
Compare the difference between the effects of 60-day or 30-day MJOs:

- 60-day MJOs zonal current
- 30-day MJOs zonal current
- 60-day MJOs SST
- 30-day MJOs SST
**A run with oscillating winds on a resting ocean. No other forcing.**

In this run the ocean was initialized with flat isotherms and zero currents. Winds and thermal forcing remained zero throughout, except for weak MJO-like oscillating winds (60-day period, amplitude 1 m/s) over the western equatorial region (the first figures in this set show the region of the wind). The oscillating wind forcing has zero mean. - Mean surface zonal current
- Mean sea level
- Mean circulation in the zonal-vertical plane on the equator: U and vector u,w. U and contour w.
- Mean v and w in the meridional plane at 150°E due to MJOs
- Mean v,w vectors in the meridional plane at 150°E due to MJOs
- Mean w and u,v vectors in the surface layer due to MJOs
- 60-day running mean zonal current at 0°, 170°E (z,t)
- 60-day running mean surface zonal current at the equator (x,t)
- 60-day running mean layer-4 zonal current (x,t)
- Mean zonal momentum nonlinear terms (surface)
**A run with 6m/s MJO winds, including windspeed and clouds.**

- Mean SST difference with MJO (stress+speed+cloud)
- SST difference on the equator (stress+speed+cloud)
**A run with 6m/s MJO winds, including windspeed but no clouds.**

- Mean SST difference with MJO (stress+speed+cloud)
- SST difference on the equator (stress+speed+cloud)

The main (?) MJO page

A page documenting an idealized "canonical" MJO

The main figures page