Time-longitude (Hovmoller) section of various OLR products averaged from 15S to 2.5S. Shaded is the 3-day running mean total OLR field. Contoured are the anomalies calculated by filtering the total OLR for the specific regions of the wavenumber-frequency domain defined in Fig. 1a or 1b. Note the sometimes close correspondence between the solid (negative) contours of the filtered fields with the red shading (low values) of the 3-day running mean total field, indicating the significant amount of variability of the OLR that is captured by the MJO and convectively coupled equatorial waves. Times when there is not a close correspondence between the total OLR field and the contours of the filtered fields are an indication of convective events that cannot be attributed to the MJO or convectively coupled equatorial waves, and these events contribute to the red background spectrum removed from Figs. 1a and 1b.
For a similar plot, but showing the 3-day running mean OLR anomalies (with mean and seasonal cycle removed) as the shaded field, click here.