| Many atmospheric phenomena such as Madden-Julian Oscillation, Hadley cell, equatorially trapped waves, and storm tracks are manifestations of the interactions between atmospheric flows at multiple scales and convection. In this thesis, a combination of mathematical modeling, numerical simulations, and data analysis, is used to improve the understanding of the mechanisms of coupling between moist convection and atmospheric circulation. The feedback between convectively coupled Kelvin waves (CCKWs) and the Intertropical Convergence Zone (ITCZ) is first investigated using an idealized model for the tropical atmosphere. Modeled CCKWs are shown to develop a meridional circulation and their speed of propagation ranges from the dry gravity wave (about 50 ms -1), along a narrow ITCZ, to the moist gravity wave (about 15 ms -1), along a wide ITCZ. Statistical analysis of tropical data is then used to validate the theoretical predictions for the modulation of the speed of CCKWs by the geographic distribution of the ITCZ. In the final chapter, a modeling study is presented to investigate the coupling among earth's rotation, gravity waves, and moist convection, in the context of a geostrophic adjustment problem. This study shows that an initial imbalance in precipitation induces a circulation that further enhances precipitation; however, the behavior of the flow depends critically on the ratio between planetary rotation and convective adjustment time. |
