...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of the Atmospheric Sciences >Reexamining the dynamics of short-scale, diabatic Rossby waves and their role in midlatitude moist cyclogenesis
【24h】

Reexamining the dynamics of short-scale, diabatic Rossby waves and their role in midlatitude moist cyclogenesis

机译：重新审查短尺度，绝热Rossby波的动力学及其在中纬度湿循环过程中的作用

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

As a step toward a more comprehensive study of the physical processes that underlie explosive cyclogenesis, a two-dimensional, semigeostrophic model with a now standard parameterization of latent heat release is used to diagnose the structure, energetics, and propagation characteristics of short-scale, diabatic normal modes in a moist, baroclinic atmosphere with the Eady basic state. Upon revisiting the inviscid problem, it is found that when a thermodynamically consistent vertical profile of latent heat release is used, the short-wave cutoff vanishes, and growth rates become independent of zonal wavelength for zonal wavelengths shorter than approximately 1900 kin. The destabilized short-scale modes, identified previously as diabatic Rossby waves, owe their existence to the continuous generation of potential vorticity by moist processes associated with warm air advection, rising motion, and latent heat release. To determine if these short-scale, diabatic Rossby wave modes continue to grow at small but finite amplitudes in the presence of frictional damping, a standard Ekman boundary layer with quadratic surface drag is employed. It is found that exponential growth is robust over a wide range of zonal wavelengths during the incipient phase of moist cyclogenesis and that, once generated, the short-scale, diabatic modes persist even in the presence of "realistic" surface friction. Finally, observations have shown that a number of explosive cyclones exhibit two stages of development. The first stage, prior to the period of most rapid deepening, involves the spinup of surface vorticity that can occur independent of upper-level forcing. The results of this study, in conjunction with recent observational work, provide compelling evidence that a diabatic Rossby wave may possibly serve as a precursor, low-level cyclonic disturbance. It is advocated here that an understanding of these small-scale, "moist" coherent structures is vital to describe the life cycle of extratropical cyclones in moist, baroclinic environments. [References: 48]
机译：为了更全面地研究爆炸性循环发生基础的物理过程，采用了二维半地转模型（现在具有潜热释放的标准参数化参数）来诊断短尺度的结构，能量学和传播特征，处于Eady基本状态的潮湿斜压大气中的非绝热正常模式。再次研究了无形的问题后，发现当使用热力学上一致的潜热释放垂直剖面时，短波截止消失，并且对于小于大约1900 kin的纬向波长，生长速度变得不受纬向波长的影响。不稳定的短尺度模式以前被称为绝热的Rossby波，其存在是由于与热空气对流，上升运动和潜热释放相关的潮湿过程不断产生潜在的涡度。为了确定这些短尺度的非绝热Rossby波模式是否在存在摩擦阻尼的情况下以较小但有限的幅度继续增长，采用了具有二次表面阻力的标准Ekman边界层。发现在湿气循环发生的初始阶段，指数增长在很宽的纬向波长范围内都很稳定，并且一旦产生，即使在存在“现实的”表面摩擦的情况下，短尺度的非绝热模式仍然存在。最后，观察结果表明，许多爆炸性旋风显示出两个发展阶段。在最快速加深阶段之前的第一阶段涉及表面涡旋的旋转，旋涡可能独立于高层强迫而发生。这项研究的结果，结合最近的观测工作，提供了令人信服的证据，即绝热的罗斯比波可能是前兆，低水平的气旋扰动。在此提倡对这些小规模，“潮湿”的相干结构的理解对于描述湿润，斜压环境中温带气旋的生命周期至关重要。 [参考：48]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号