Multiple Equilibria of the Hadley Circulation in an Intermediate-Complexity Axisymmetric Model
Multiple Equilibria of the Hadley Circulation in an Intermediate-Complexity Axisymmetric Model
复制标题
中等复杂度轴对称模型中哈德来环流的多重平衡
DOI：
10.1175/2009jcli3105.1
复制
发表时间：
2010
影响因子：
4.9
通讯作者：
A. Sobel
中科院分区：
文献类型：
--
作者：
G. Bellon;A. Sobel
基于准平衡理论的中等复杂模式——具有预测大气边界层的准平衡热带环流模式，以及两个自由对流层动量模态和一个湿度模态和一个温度模态——在纬向对称水行星配置中研究了Hadley环流对海表温度纬向分布的敏感性。对于热带海温梯度大的赤道对称海温强迫，模式模拟了经典的双Hadley环流和一个赤道热带辐合带（ITCZ）。对于热带的小海温梯度，该模式表现出多个平衡，一个赤道对称平衡和两个非对称平衡（互为镜像），具有一个离赤道的ITCZ。对模型中所起作用的反馈的进一步研究表明，假设的温度变化的垂直结构对温度变化的存在和稳定至关重要。
Abstract A model of intermediate complexity based on quasi-equilibrium theory—a version of the Quasi-Equilibrium Tropical Circulation Model with a prognostic atmospheric boundary layer, as well as two free-tropospheric modes in momentum, and one each in moisture and temperature—is used in a zonally symmetric aquaplanet configuration to study the sensitivity of the Hadley circulation to the sea surface temperature (SST) latitudinal distribution. For equatorially symmetric SST forcing with large SST gradients in the tropics, the model simulates the classical double Hadley cell with one equatorial intertropical convergence zone (ITCZ). For small SST gradients in the tropics, the model exhibits multiple equilibria, with one equatorially symmetric equilibrium and two asymmetric equilibria (mirror images of each other) with an off-equatorial ITCZ. Further investigation of the feedbacks at play in the model shows that the assumed vertical structure of temperature variations is crucial to the existence and stabil...