Responses of the circulation and water mass in the Beibu Gulf to the seasonal forcing regimes
Responses of the circulation and water mass in the Beibu Gulf to the seasonal forcing regimes
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DOI：
10.1007/s13131-014-0506-6
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发表时间：
2014-06
影响因子：
1.4
通讯作者：
Jingsong Gao;M. Shi;Bo Chen;Peifang Guo;D. Zhao
中科院分区：
文献类型：
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作者：
Jingsong Gao;M. Shi;Bo Chen;Peifang Guo;D. Zhao
在过去的20 a中，北部湾的海湾尺度环流通常被认为是由风应力或密度梯度驱动的。然而，利用三维斜压模式进行的三次敏感性试验揭示了北部湾环流的形成机制：北方环流全年受季风驱动，而北部湾南部环流则分别在冬、夏季受季风和南海环流驱动。热通量和潮汐谐波对北部湾环流的强度和范围以及局地环流结构都有很大的影响，但对北部湾主要环流结构没有影响。另一方面，由于热量的输入产生了季节性的温跃层，阻止了上层热水和下层冷水的垂直混合，在没有热量输入的情况下，北部湾冷水团将消失。另外，北方海湾的风致气旋性环流有利于大涡的存在。然而，没有潮汐谐波的力量，BGCWM的覆盖面积略有增加。当模式由月平均的地面强迫驱动时，环流结构发生了一定的变化，模式的覆盖范围几乎100%向外扩展，表明北部湾环流和水团对地面强迫的时间分辨率有较强的响应。
In the past 20 a, the gulf-scale circulation in the Beibu Gulf has been commonly accepted to be driven by a wind stress or density gradient. However, using three sensitive experiments based on a three-dimensional baroclinic model that was verified by observations, the formation mechanisms were revealed: the circulation in the northern Beibu Gulf was triggered by the monsoon wind throughout a year; whereas the southern gulf circulation was driven by the monsoon wind and South China Sea (SCS) circulation in winter and summer, respectively. The force of heat flux and tidal harmonics had a strong effect on the circulation strength and range, as well as the local circulation structures, but these factors did not influence the major circulation structure in the Beibu Gulf. On the other hand, the Beibu Gulf Cold Water Mass (BGCWM) would disappear without the force of heat flux because the seasonal thermocline layer was generated by the input of heat so that the vertical mixing between the upper hot water and lower cold water was blocked. In addition, the wind-induced cyclonic gyre in the northern gulf was favorable to the existence of the BGCWM. However, the coverage area of the BGCWM was increased slightly without the force of the tidal harmonics. When the model was driven by the monthly averaged surface forcing, the circulation structure was changed to some extent, and the coverage area of the BGCWM almost extended outwards 100%, implying the circulation and water mass in the Beibu Gulf had strong responses to the temporal resolution of the surface forces.