飓风Isidore与海洋相互作用数值模拟研究

A Numerical Simulation of Interaction Between Hurricane Isidore and Ocean

本文利用MM5大气模型和HYCOM海洋环流模型,模拟研究了2002年飓风Isidore过境墨西哥湾后上层海洋的响应以及墨西哥湾常态水(Gulf common water,GCW)和湾流(Loop Current,LC)对飓风Isidore的不同响应。飓风Isidore穿过GCW区后,导致海表最大降温接近5℃,混合层深度由30m加深到70m,上层海洋损失热量较多,上层海洋的结构恢复时间较长;但在LC区,由于亚热带持续不断的高温、高速水体输运,该区域水体具有较深的混合层和较大的能量,虽然在飓风过程中损失了较多的热量,但仅造成2℃的海表面降温,上层海洋的结构恢复时间较短;此外,飓风过境后,在上层海洋激发近惯性震荡,在LC区可导致1.0m/s近惯性震荡流,能量可传播至1500m以深,但在GCW区,由于较浅的上混合层、较弱的流速和较强的层化结构,近惯性震荡运动影响深度较浅。

The Hybrid Coordinate Ocean Model(HYCOM) was used in this study to examine the different ocean feedback of Gulf Common Water(GCW) and Loop Current(LC) to hurricanes during the 2002 hurricane season. The HYCOM simulations was coincided well with the satellite observations, which showed a similar SST cooling scope and a obvious maximum SST cooling close to 5 C cross the Yucatan Shelf after hurricane Isidore. the mixing layer depth increased form 25 m to about 70 m. In LC region, because of its deep mixing layer(ML) and persistent heat and kinetic energy transports from the subtropical ocean, the maximum SST cooling was only about 2 C. After hurricanes, near-inertial oscillation dominated the upper ocean which could cause near-inertial currents more than 1.0 m/s in LC region, the induced energy could transfer to the interior ocean more than 1500 m. However, the energy propagation depth decreased to about 1000 m in GCW region, which may be caused by its shallow mixing layer, weak currents and strong stratification.