Evaluating theories of convectively-coupled equatorial waves using observations of 2-day waves

There are multiple, conflicting explanations for convectively coupled equatorial waves (CCEWs). Fortunately, most if not all of these theories are testable, because they make predictions about phase and amplitude relationships of various kinematic and thermodynamic variables. In this study the authors test theories of CCEWs using observations of 2-day waves. These waves were well sampled by TOGA COARE, which produced some of the most reliable measurements of large-scale divergence, heating, and moistening in addition to surface fluxes, making 2-day waves excellent candidates for such tests. Moreover, 2-day waves (also referred to as westward-inertio gravity (WIG) waves) share their equivalent depth and probably their propagation mechanism with other CCEWs, so conclusions drawn from this analysis may apply to a broad spectrum of CCEWs. The energetics and dynamics of the composite COARE 2-day wave are analyzed using a moist static energy budget and a vertical mode decomposition. The authors examinine whether the structure and equivalent depth of the wave are consistent with: 1) the gross moist static stability concept; 2) quasi-equilibrium theory; and 3) two-vertical-mode models of equatorial waves.