Observed Structure of Convectively Coupled Waves as a Function of Equivalent Depth: Kelvin Waves and the Madden Julian Oscillation

Figure 3. Horizontal maps of regressed OLR anomalies (shading, Wm^-2), geopotential height anomalies (positive in red, contour interval 0.15m), and wind anomalies at 900 hPa for signals along the Kelvin wave dispersion solutions for zonal wave number 4. Panels correspond to equivalent depths of 90, 25, 12, 8, and 5m, corresponding to the same panels of Fig. 2.

Figure 4. a. Anomalies of 900 hPa wind (vectors), OLR (shading, with negative in blue), and geopotential height (with negative anomalies in blue) regressed against OLR anomalies filtered in the wave number frequency domain for the MJO. b. Vertical cross section of zonal wind (shading) and geopotential height anomalies (contours, with negative in blue) on the equator, plotted against regressed total geopotential height.

Figure 5. Shading shows the result of regressing absolute value of OLR anomalies along the Kelvin wave dispersion curves for zonal wave numbers 3-8 against MJO-filtered OLR anomalies at 80E (Wm^-2). The local mean is subtracted at each grid point. The shading thus provides a measure of how Kelvin wave activity at particular equivalent depths varies with the local phase of the MJO. Red (blue) shading thus represents anomalously active (suppressed) mean OLR anomaly amplitude at the equivalent depth noted in the panel title. Contours represent regressed MJO-filtered OLR anomalies, with negative in blue (the interval is 5Wm^-2 with the zero contour omitted). Panels a through e show results for signals along Kelvin wave dispersion solutions at equivalent depths of 90, 25, 12, 8, and 5m (respectively).