The Role of Unbalanced Motion in the Upper Troposphere and Stratosphere

9903514 Dunkerton，NWRA“对流层上部和平流层不平衡运动的作用”运动的不平衡分量--包括重力波、惯性不稳定性和强迫环流--对大气中大尺度平衡流的演变至关重要。 主要研究者和同事将研究与热带对流层，平流层和中间层以及对流层和平流层外的不平衡动力学的几个方面，试图了解这些不平衡运动是如何产生的。 PI将研究：（1）近赤道Rossby波临界层对不平衡气流不稳定的稳定性，包括惯性和辐散正压不稳定。 当来自中纬度的行星Rossby波将异常位涡（PV）引入冬季半球，同时建立反向的PV纬向梯度时，会发生局部不稳定。 局部不稳定性的结构和增长率将被探索为实际的位涡分布。(2)重力波在准两年振荡和半年振荡中的作用。 PI将使用一个新的参数化重力波诱导力的这项研究，和平均垂直切变的重力波动量通量的诊断措施将扩展到赤道捕获模式。 (3)物体力对哈德利环流的影响。 (4)在一个理想的斜压生命周期中，利用一个数值模式激发惯性重力波，其中斜压不稳定的类型在更大的生命周期范围内变化。 (5)急流附近观测到的浅层扰动的性质。 将与京都大学的Kaoru Sato博士合作进行一项研究，分析中高层大气雷达和日本无线电探空仪对速度层的观测。 (6)惯性重力波在对流层顶附近输送中的作用。 这也将与佐藤博士合作完成，并将使用高分辨率大气环流模型的模拟。

9903514Dunkerton, NWRA"The Role of Unbalanced Motion in the Upper Troposphere and Stratosphere" The unbalanced component of motion - consisting of gravity waves, inertial instabilities and forced circulations - is essential to the evolution of large-scale balanced flow in the atmosphere. The principal investigator and colleagues will examine several aspects of unbalanced dynamics relevant to the tropical troposphere, stratosphere, and mesosphere as well as the extratropical upper troposphere and stratosphere in an attempt to understand how these unbalanced motions are produced. The PI will examine:(1) the stability of the near-equatorial Rossby-wave critical layer to unbalanced flow instabilities, including inertial and divergent barotropic instability. Local instabilities occur as planetary Rossby waves from midlatitudes draw anomalous potential vorticity (PV) into the winter hemisphere while setting up a reversed meridional gradient of PV. The structure and growth rate of local instabilities will be explored for realistic distributions of potential vorticity.(2) the role of gravity waves in the quasi-biennial and semiannual oscillations. The PI will use a new parameterization for gravity wave induced force for this study, and a diagnostic measure of gravity wave momentum flux in mean vertical shear will be extended to equatorially trapped modes. (3) the effect of body forces on the Hadley circulations. (4) the excitation of inertia-gravity waves (IGWs) in an idealized baroclinic lifecycle using a numerical model in which type of baroclinic instability is varied over a wider range of lifecycles. (5) the nature of observed shallow disturbances near the jetstream. Observations from the Middle and Upper Atmosphere (MU) radar and Japanese rawinsonde observations of velocity layers will be analyzed in a collaborative study with Dr. Kaoru Sato of Kyoto University. (6) the role of inertia-gravity waves in transport near the tropopause. This also will be done in collaboration with Dr. Sato and will use simulations from a high-resolution general circulation model.