Simulated seasonal and interannual variability of the mixed layer heat budget in the northern Indian Ocean
Simulated seasonal and interannual variability of the mixed layer heat budget in the northern Indian Ocean
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DOI：
10.1175/jcli4148.1
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发表时间：
2007-07-01
影响因子：
4.9
通讯作者：
Madec, Gurvan
中科院分区：
文献类型：
--
作者：
de Boyer Montegut, Clement;Vialard, Jerome;Madec, Gurvan
利用一个全球海洋环流模式（OGCM）研究了北方印度洋（NIO）混合层热量收支。该模型对观测结果进行了验证，并与NIO中的混合层深度数据表现出相当好的一致性。NIO分为三个子盆地：阿拉伯海西部（AS），阿拉伯海东部（AS）和孟加拉湾（BoB）。这项研究揭示了西部和东部的AS热收支之间的强烈差异，而后者的盆地与BoB的相似之处。有趣的新的结果显示在季节性的时间尺度。由于两个原因，需要考虑太阳热通量的渗透。首先，一年中在混合层下面平均损失28 W m（-2）。其次，太阳热通量的渗透往往减少太阳热通量的SST季节循环的影响，在AS，因为最强的通量的季节也是季节与薄的混合层。这增强了潜热通量对SST季节变率的控制。盐度对SST变率的影响进行了论证。盐度分层起着明显的作用，在保持高的冬季SST在BoB和东部的AS，而不是在西部的AS。地表附近淡水的存在使得热量储存在表层以下，这些热量可以在冬季冷却期间通过夹带变暖来恢复（在BoB中，冬季贡献为+ 2.1摄氏度左右C）。在年际时间尺度上，东部的AS和BOB强烈的控制风通过潜热通量异常。在AS西部，垂直过程以及水平平流对SST年际变化的贡献很大，风不是控制热通量强迫的唯一因素。
A global ocean general circulation model (OGCM) is used to investigate the mixed layer heat budget of the northern Indian Ocean (NIO). The model is validated against observations and shows fairly good agreement with mixed layer depth data in the NIO. The NIO has been separated into three subbasins: the western Arabian Sea (AS), the eastern AS, and the Bay of Bengal (BoB). This study reveals strong differences between the western and eastern AS heat budget, while the latter basin has similarities with the BoB. Interesting new results on seasonal time scales are shown. The penetration of solar heat flux needs to be taken into account for two reasons. First, an average of 28 W m(-2) is lost beneath the mixed layer over the year. Second, the penetration of solar heat flux tends to reduce the effect of solar heat flux on the SST seasonal cycle in the AS because the seasons of strongest flux are also seasons with a thin mixed layer. This enhances the control of SST seasonal variability by latent heat flux. The impact of salinity on SST variability is demonstrated. Salinity stratification plays a clear role in maintaining a high winter SST in the BoB and eastern AS while not in the western AS. The presence of freshwater near the surface allows heat storage below the surface layer that can later be recovered by entrainment warming during winter cooling (with a winter contribution of + 2.1 degrees C over left right C in the BoB). On an interannual time scale, the eastern AS and BoB are strongly controlled by the winds through the latent heat flux anomalies. In the western AS, vertical processes, as well as horizontal advection, contribute significantly to SST interannual variability, and the wind is not the only factor controlling the heat flux forcing.