Convectively Coupled Equatorial Waves. Part I: Horizontal and Vertical Structures
Convectively Coupled Equatorial Waves. Part I: Horizontal and Vertical Structures
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对流耦合赤道波。
DOI：
10.1175/jas4017.1
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发表时间：
2007
影响因子：
3.1
通讯作者：
Yang G
中科院分区：
文献类型：
--
作者：
Yang G
利用多层15a ECMWF再分析(ERA-15)资料和1992年5-10月卫星观测的亮温资料，研究了赤道对流耦合波的水平和垂直结构。使用先前开发的方法来隔离动力波。利用对流与动力结构之间的线性回归/相关关系，得到了对流耦合赤道波的复合结构。研究发现，这种关系取决于环境气流和对流耦合的性质，并且在赤道外和赤道中心对流、不同半球和季节之间存在差异。西半球的开尔文波结构与经典赤道波理论基本一致，其对流位于低层辐合区。在东半球，开尔文波在低对流层西风增强和垂直结构倾斜的区域倾向于对流。开尔文波也倾向于在500百帕的纬向风振幅中有第三个峰值，并向上传播到低平流层。低对流层西移混合Rossby重力(WMRG)和n=1 Rossby(R1)波结构及其与对流的关系与经典的赤道波动理论和隐含的低对流层辐合是一致的。在东半球，WMRG波和R1波在垂直方向上具有第一斜压模结构。然而，在西半球，R1波具有正压结构。在东半球，R1波和Kelvin波一样，在低层西风增强区倾向于赤道对流，这表明与这些波相关的增强的地表能量通量可能对这个暖水半球的赤道对流起到重要的组织作用。在对流层上层，东半球存在东移的Rossby重力(EMRG)和n=1重力波，西半球存在东移的WMRG和R1波，这表明环境气流使波发生了多普勒频移。
Multilevel 15-yr ECMWF Re-Analysis (ERA-15) and satellite-observed brightness temperature (Tb) data for the period May–October 1992 are used to examine the horizontal and vertical structures of convectively coupled equatorial waves. Dynamical waves are isolated using a methodology developed previously. Composite structures of convectively coupled equatorial waves are obtained using linear regression/correlation between convection (Tb) and dynamical structures. It is found that the relationship depends on the ambient flow and the nature of the convective coupling, and varies between off-equatorial- and equatorial-centered convection, different hemispheres, and seasons.The Kelvin wave structure in the Western Hemisphere is generally consistent with classic equatorial wave theory and has its convection located in the region of low-level convergence. In the Eastern Hemisphere the Kelvin wave tends to have convection in the region of enhanced lower-tropospheric westerlies and a tilted vertical structure. The Kelvin wave also tends to have a third peak in zonal wind amplitude at 500 hPa and exhibits upward propagation into the lower stratosphere. Lower-tropospheric westward-moving mixed Rossby–gravity (WMRG) andn= 1 Rossby (R1) wave structures and their relationship with convection are consistent with classic equatorial wave theory and the implied lower-tropospheric convergences. In the Eastern Hemisphere the WMRG and R1 waves have first baroclinic mode structures in the vertical. However, in the Western Hemisphere, the R1 wave has a barotropic structure. In the Eastern Hemisphere the R1 wave, like the Kelvin wave, tends to have equatorial convection in the region of enhanced lower-level westerlies, suggesting that enhanced surface energy fluxes associated with these waves may play an important organizing role for equatorial convection in this warm-water hemisphere.In the upper troposphere, eastward-moving Rossby–gravity (EMRG) andn= 1 gravity waves are found in the Eastern Hemisphere, and eastward-moving WMRG and R1 waves are found in the Western Hemisphere, suggestive of Doppler shifting of waves by the ambient flow.
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发表时间：
1997
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P. Pires;J. Redelsperger;J. Lafore
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DOI：
--
发表时间：
2006
期刊：
影响因子：
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作者：
M. Ringer;G. Martin;C. Z. Greeves;T. Hinton;P. James;V. Pope;Adam A. Scaife;R. Stratton;P. Inness;J. Slingo;Gui‐Ying Yang
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DOI：
--
发表时间：
1995
期刊：
影响因子：
--
作者：
T. Dunkerton;F. X. Crum
通讯作者：
F. X. Crum
影响因子：
3.1
作者：
Yang G
通讯作者：
Yang G