The Role of Convective Inhibition in Convectively-Coupled Tropical Waves

We find strong evidence of a triggering mechanism related to convective inhibition in spectral-filtered lagged and cross-correlated regressions, composites and individual cases in the Indian and West Pacific basins. We use a simple linear index to illustrate the degree of deep convective inhibition at each location. This index therefore expresses the degree of disequilibrium between a nominal boundary layer and the lower troposphere.

This index becomes negative preceding the precipitation maximum that characterizes both convectively coupled Kelvin wave and MJO events. This suggests that a lower-tropospheric quasi-equilibrium plays a role in triggering the convective events related to these phenomena.