Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1175/JAS-D-17-0173.1 |
Effect of Overturning Circulation on Long Equatorial Waves: A Low-Frequency Cutoff | |
Back, Amanda1,2; Biello, Joseph A.1 | |
2018-05-01 | |
发表期刊 | JOURNAL OF THE ATMOSPHERIC SCIENCES |
ISSN | 0022-4928 |
EISSN | 1520-0469 |
出版年 | 2018 |
卷号 | 75期号:5页码:1721-1739 |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | Zonally long tropical waves in the presence of a large-scale meridional and vertical overturning circulation are studied in an idealized model based on the intraseasonal multiscale moist dynamics (IMMD) theory. The model consists of a system of shallow-water equations describing barotropic and first baroclinic vertical modes coupled to one another by the zonally symmetric, time-independent background circulation. To isolate the effects of the meridional circulation alone, an idealized background flow is chosen to mimic the meridional and vertical components of the flow of the Hadley cell; the background flow meridionally converges and rises at the equator. The resulting linear eigenvalue problem is a generalization of the long-wave-scaled version of Matsuno's equatorial wave problem with the addition of meridional and vertical advection. The results demonstrate that the meridional circulation couples equatorially trapped baroclinic Rossby waves to planetary, barotropic free Rossby waves. The meridional circulation also causes the Kelvin wave to develop an equatorially trapped barotropic component, imparting a westward-tilted vertical structure to the wave. The total energy of the linear system is positive definite, so all waves are shown to be neutrally stable. A critical layer exists at latitudes where the meridional background flow vanishes, resulting in a minimum frequency cutoff for physically feasible waves. Therefore, linear Matsuno waves with periods longer than the vertical transport time of the meridional circulation do not exist in the equatorial waveguide. This implies a low-frequency cutoff for long equatorial waves. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000434270600020 |
WOS关键词 | MADDEN-JULIAN OSCILLATION ; SHEARED ZONAL FLOW ; ROSSBY WAVES ; KELVIN WAVES ; INSTABILITY ; ATMOSPHERE ; MODEL |
WOS类目 | Meteorology & Atmospheric Sciences |
WOS研究方向 | Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/29730 |
专题 | 地球科学 |
作者单位 | 1.Univ Calif Davis, Dept Math, Davis, CA 95616 USA; 2.NOAA, Global Syst Div, ESRL, Boulder, CO USA |
推荐引用方式 GB/T 7714 | Back, Amanda,Biello, Joseph A.. Effect of Overturning Circulation on Long Equatorial Waves: A Low-Frequency Cutoff[J]. JOURNAL OF THE ATMOSPHERIC SCIENCES,2018,75(5):1721-1739. |
APA | Back, Amanda,&Biello, Joseph A..(2018).Effect of Overturning Circulation on Long Equatorial Waves: A Low-Frequency Cutoff.JOURNAL OF THE ATMOSPHERIC SCIENCES,75(5),1721-1739. |
MLA | Back, Amanda,et al."Effect of Overturning Circulation on Long Equatorial Waves: A Low-Frequency Cutoff".JOURNAL OF THE ATMOSPHERIC SCIENCES 75.5(2018):1721-1739. |
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