...
  • 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 >Maintenance of tropical intraseasonal variability: Impact of evaporation-wind feedback and midlatitude storms
【24h】

Maintenance of tropical intraseasonal variability: Impact of evaporation-wind feedback and midlatitude storms

机译：维持热带季节内变化：蒸发-风反馈和中纬度风暴的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

An intraseasonal tropical oscillation with a period of 20-80 days is simulated in the Neelin-Zeng Quasi-Equilibrium Tropical Circulation Model. This model is an intermediate-level atmospheric model that includes primitive equation nonlinearity, radiative-convective feedbacks, a simple land model with soil moisture, and a Betts-Miller-type moist convective adjustment parameterization. Vertical temperature and moisture structures in the model are based on quasi-equilibrium profiles taken from deep convective regions. The tropical intraseasonal variability is reasonably broadband. The eastward propagating 20-80-day variability is dominated by zonal wavenumber 1, shows features similar to an irregular Madden-Julian oscillation (MJO), and exhibits amplitude and phase speeds that vary both seasonally and between events. At higher wavenumbers, the model has a distinction between the low-frequency MJO-like band and the moist Kelvin wave band, similar to that found in observations. In the model, it is conjectured that this arises by interaction of the wavenumber-1 moist Kelvin wave with the zonally asymmetric basic state. Experiments using climatological sea surface temperature forcing are conducted using this model to examine the effects of evaporation-wind feedback and extratropical excitation on the maintenance of intraseasonal variability, with particular attention paid to the low wavenumber mode in the 20-80-day band. These experiments indicate that evaporation-wind feedback partially organizes this intraseasonal variability by reducing damping, but it is not by itself sufficient to sustain this oscillation for the most realistic parameters. Excitation by extratropical variability is a major source of energy for the intraseasonal variability in this model. When midlatitude storms are suppressed, tropical intraseasonal variability is nearly eliminated. However, the eastward propagating intraseasonal signal appears most clearly when midlatitude excitation is aided by the evaporation-wind feedback. [References: 78]
机译：在Neelin-Zeng准平衡热带环流模型中模拟了一个20-80天的季节内热带振荡。该模型是一个中层大气模型，包括原始方程非线性，辐射对流反馈，具有土壤水分的简单土地模型以及贝茨-米勒式湿对流调节参数化。模型中的垂直温度和湿度结构是基于从深对流区获得的准平衡剖面。热带季节内的变异性是合理的宽带。向东传播的20-80天变异受1号纬向波控制，显示出类似于不规则的Madden-Julian振荡（MJO）的特征，并且表现出振幅和相速度随季节和事件之间变化。在较高的波数下，该模型在类似于MJO的低频频带和潮湿的Kelvin频带之间具有区别，这与观测结果相似。在模型中，推测这是由于波数为1的湿开尔文波与区域不对称基本状态的相互作用引起的。使用该模型进行了气候海面温度强迫实验，以检验蒸发风反馈和温带激发对维持季节内变异性的影响，尤其要注意20-80天波段的低波数模式。这些实验表明，蒸发风反馈通过减少阻尼来部分组织这种季节内的变化，但是对于最现实的参数而言，它本身不足以维持这种振荡。温带变异性的激发是该模型季节内变异性的主要能量来源。当中纬度风暴被抑制时，热带的季节内变化几乎被消除。但是，当中纬度激发受蒸发-风反馈的辅助时，向东传播的季节内信号最明显。 [参考：78]

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