Isentropic Mass Exchange between the Tropics and Extratropics in the Stratosphere
Isentropic Mass Exchange between the Tropics and Extratropics in the Stratosphere
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DOI：
10.1175/1520-0469(1994)051
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发表时间：
1994-10
影响因子：
3.1
通讯作者：
Ping Chen;J. Holton;A. O'Neill;R. Swinbank
中科院分区：
文献类型：
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作者：
Ping Chen;J. Holton;A. O'Neill;R. Swinbank
摘要：利用英国气象局资料同化系统提供的风场资料，采用半拉格朗日输送模式，对1992年6月1日至10月31日以及1992年12月1日至1993年4月30日期间平流层热带与温带之间的等熵质量交换进行了研究。对一种理想化的、初始呈纬向对称的示踪物进行的计算表明，在平流层中上部，尽管副热带地区存在准渗透屏障，但大部分热带空气仍被输送到冬季半球的中纬度地区。这种输送是以行星尺度的物质“舌状区”形式进行的，这些“舌状区”与冬季半球高纬度地区行星尺度波的偶发性增强相关联而向极地延伸。一旦源于热带的空气被输送到中纬度地区，它就在“冲浪区”与中纬度空气不可逆地混合。然而，源于热带的空气很难渗透到冬季极地的内部……
Abstract The isentropic mass exchange between the Tropics and extratropics in the stratosphere is investigated with a semi-Lagrangian transport model for the periods from 1 June to 31 October 1992 and from 1 December 1992 to 30 April 1993 using winds from the U.K. Meteorological Office data assimilation system. Calculations with an idealized, initially zonally symmetric tracer show that in the middle and upper stratosphere the bulk of tropical air is transported into the midlatitudes of the winter hemisphere although there exist quasi-permeable barriers in the subtropics. The transport takes place in the form of planetary-scale “tongues” of material that are drawn poleward in association with the episodic amplification of planetary-scale waves in high latitudes of the winter hemisphere. Once air of tropical origin is transported to the midlatitudes it is irreversibly mixed with the midlatitude air in the “surf zone.” Air of tropical origin can, however, hardly penetrate into the interior of the winter pol...