Dynamics and Maintenance of the Intertropical Convergence Zones

热带辐合带(ITCZ)是地球大气中的气候学特征，与热带大尺度经向环流(Hadley)和低纬地面环流密切相关。ITCZ驱动经向环流单元，将动量和多余的热量从热带输送到中纬度，从而影响中纬度的斜压性，从而影响气候。此外，东太平洋ITCZ似乎在大的厄尔尼诺/南方涛动气候波动中发挥了作用。然而，人们对维持热带辐合带的过程的动力学和能量学知之甚少。本文利用热带大气的一般环流模式和简化的三层模式，研究了ITCZ现象及其相关大尺度环流的维持。PI将通过一套精心设计的具有越来越复杂的强迫的GCM实验，探索表面边界加热(海洋表面温度)和地形如何影响ITCZ的位置、强度、能量和动力学。将建立一个热带大气的三层模式，并用于解释GCM实验(该模式将显式地解析边界层和自由斜压热带对流层环流)。这些结果将有助于更好地确定ITCZ与大尺度经向环流和地面环流的关系，从而有助于我们对全球气候的了解。

The Intertropical Convergence Zones (ITCZs) are climatological features in the earth's atmosphere that are intimately tied to both the tropical large-scale meridional (Hadley) circulation and the low-latitude surface circulation. The ITCZs drive the meridional circulation cells which transport momentum and excess heat from the tropics to midlatitudes, thereby affecting the baroclinity of the midlatitudes and hence climate. In addition, the eastern Pacific ITCZ appears to play a role in the large El Nino/Southern Oscillation climate fluctuations. Yet the dynamics and energetics of the processes maintaining the Intertropical Convergence Zones are poorly understood. This study examines the maintenance of the ITCZ phenomenon and the associated large-scale circulation, using a General Circulation Model and a simplified 3-layer model of the tropical atmosphere. The PI will explore how the surface boundary heating (sea surface temperature) and orography effect the location, strength, energetics and dynamics of the ITCZ through a carefully designed set of GCM experiments with increasingly complicated forcing. A 3-layer model of the tropical atmosphere will be constructed and employed to facilitate in the interpretation of the GCM experiments (this model will explicitly resolve the boundary layer and the free baroclinic tropical tropospheric circulations). The results will help to better define the relationship between the ITCZ and large-scale meridional and surface circulations, and hence contribute to our knowledge of the global climate.