对流耦合MRG波西传过程中的垂直结构变化及湿过程的作用机制

对流耦合的混合Rossby重力（MRG）波是热带太平洋对流层中最主要的波动现象之一。已有的研究表明，MRG波的水平结构会随着波动的西传而发生系统性的变化。然而，之前受限于资料的分辨率，MRG波西传过程中垂直结构的变化，并没有被很好地揭示。以往的研究往往通过基本气流的作用来解释波动的这种结构变化。然而，伴随着结构的变化，波动中对流降水的耦合特征也会随之改变。理论上说，降水导致的非绝热加热、水汽的输送等大气湿过程在对流耦合MRG波的变化过程中应能起到重要作用，但其过程并没有被揭示。本研究拟使用高分辨率的再分析资料、卫星观测资料、以及海上的各种通量资料，综合使用统计分析、动力热力诊断和数值试验的方法，从MRG波西传过程中的垂直结构的变化的特征入手，提出大气湿过程对MRG波西传过程中垂直结构发生变化的影响机制。并且，本研究还拟提出和讨论MRG波西传过程中的动能下传对于深对流活动具有激发的作用。

Convectively coupled mixed-Rossby gravity (MRG) wave is one of most prevalent disturbances in troposphere over the tropical Pacific Ocean. Previous studies indicated that horizontal structure of MRG waves changed systematically along with westward propagation. However, the changes in vertical structure of MRG waves were not well reported due to the limitation of the low-resolution data before. Role of large-scale mean flow is commonly applied to explain such changes in wave structure. Nevertheless, features of convective precipitation coupled to equatorial waves change systematically as well accompanied with change in dynamical structure. It remains vague on the roles of atmospheric moist processes, e.g., diabatic heating associated with precipitation, moisture transport, on the change in structure of westward propagating convectively coupled MRG waves, in which the moist processes should be important in determining the wave structure in theoretical. In this study, by using high-resolution reanalysis data, satellite observations, and various observational flux data over the ocean, applying statistical analysis, dynamical and thermodynamical diagnose, and numerical experiment, the characteristics of the change in the vertical structure will be investigated at first. Then, we plan to propose the roles and mechanism of atmospheric moist processes on the changes in the vertical structure of MRG waves during westward propagation of these waves. Moreover, a stimulation mechanism of the downward energy transport during westward propagation of MRG waves on deep convection development will be proposed and discussed.