加勒比海三重双向嵌套三维环流模型的应用

A 3D ocean circulation model with triply two-way nesting-technique applied in Caribbean Sea

对三重双向嵌套海洋环流三维数值模型系统(CANDIE),用尤卡坦海峡实测横断面流速和海温等值线、1990年代根据卫星跟踪漂移轨迹推求得到的15m水深处的时间平均流场、实测平均海温过程和西加勒比海体积输送流函数等资料进行了验证,结果表明所建三重双向嵌套模型系统结构与参数合理,模型能较好地模拟西加勒比海的环流特征如加勒比流、巴拿马-哥伦比亚漩涡和该地区温盐的季节性变化。模型被用来计算小模型计算域(伯利兹大陆架)珊瑚礁地区不同水深处悬浮颗粒的运动轨迹线、颗粒的保留与耗散。近表层耗散在Lighthouse Reef Atoll和Glovers Reef Atolls以东相对较强,在内大陆架特别在Inner Channel内和South Water Cay附近相对较低。为了测试伯里兹大陆架海表面珊瑚礁之间的水动力连接特性,计算了位于Turneffe Islands Atoll和GloversReef Atolls珊瑚礁的上游颗粒来源区(源)和下游颗粒耗散区(汇),在30天内到达这两处环形珊瑚礁的近表面颗粒的可能来源区包括该两者周围的浅水区域、两者之间的深水区域和洪都拉斯Bay Islands的沿岸水域,Turneffe和Glovers Reef Atolls 30天下游耗散区分别覆盖了伯里兹大陆架的中部和南部水域。

The ocean circulation model with triply two-way nesting-technique is verified using the data of velocity and sea temperature along the transect of Yucatan Strait, time-mean currents inferred from the trajectories of satellite-tracked 15m drogue drifters in the 1990s, climatological monthly mean temperature and the volume transportation stream function in the western Caribbean Sea （WCS）. The results show that the structure and parameters of the nesting model system are reasonable. The main circulation features simulated by the model system, for instance, the Caribbean Current, the Panama-Colombia Gyre and the seasonal variations of the T/S fields in the western Caribbean Sea, are consistent with the known facts in the region. The nesting model system is applied to calculate the trace, retention and dispersion of the passive particles released at different water depth of the coral reefs in the Belize Shelf （inner model domain）. The near-surface dispersion is relatively higher to the east of the Lighthouse and the Glovers Reef Atolls, and lower in the inner shelf, particularly within the Inner Channel and in the vicinity of the South Water Cay. To examine the hydrodynamic connectivity of the surface ocean in the reefs of the Belize Shelf, the upstream and downstream areas for the coral reefs of the Turneffe Islands and the Glovers Reef Atolls are calculated. The potential sources of passive, near-surface particle supply reaching these two reef atolls within 30 days include both the shallow waters around the two atolls, the deep waters between them and the coastal waters of the Bay Islands （Honduras）. The 30-day downstream areas of the Turneffe and Glovers atolls cover the central and southern Belize shelf respectively.