Instabilities in the Agulhas Retroflection Current System: a comparative model study
Instabilities in the Agulhas Retroflection Current System: a comparative model study
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阿加勒斯逆反射电流系统的不稳定性：比较模型研究
DOI：
10.1029/1999jc900283
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发表时间：
2000
影响因子：
--
通讯作者：
S. Best
中科院分区：
文献类型：
--
作者：
N. Wells;V. Ivchenko;S. Best
厄加勒斯逆反射流系统在两个海洋大气环流模型中进行了分析，即英国高分辨率南极模型 (FRAM) 和美国平行海洋计划 (POP)。结果表明，两个模型都有两个准带急流，一个偏北向西流动的急流（阿加勒斯洋流）和一个偏南向东流动的急流（阿加勒斯回流），分别作为逆反射区域的入口和出口。对两个喷流进行了不稳定性分析，结果表明不稳定波是斜压不稳定的。结果表明，这种不稳定过程在 POP 模型中得到了很好的解决，但在 FRAM 中却很难解决。 POP的能量分析表明，正压不稳定过程和斜压不稳定过程在水流系统中都发挥着重要作用，前者集中在两个水流之间的表层，后者发生在两个水流的下方。在 FRAM 中，区域能量收支表明正压不稳定是产生涡流的主要机制，而经向截面分析表明，这种情况主要发生在厄加勒斯回流的北缘。
The Agulhas Retroflection Current system is analyzed in two ocean general circulation models, U.K. Fine Resolution Antarctic Model (FRAM) and U.S. Parallel Ocean Program (POP). It is shown that both models have two quasizonal jets, a northerly westward flowing jet (Agulhas Current) and a more southerly eastward flowing jet (Agulhas Return Current), which act as the entrance and exits of the Retroflection region, respectively. An instability analysis has been performed on both jets, and the unstable waves are shown to be baroclinicly unstable. It is shown that this instability process is well resolved in the POP model but is poorly resolved in FRAM. An energy analysis of POP shows that both barotropic and baroclinic instability processes play a major role in the current systems, with the former process concentrated in the surface layers between the two currents, and the latter process occurring below the two currents. In FRAM a regional energy budget suggests that barotropic instability is the main mechanism by which the eddies are generated, and a meridional cross-sectional analysis shows that this occurs principally on the northern edge of the Agulhas Return Current.