珠江口鸡啼门近海海洋对台风的响应

RESPONSE TO TYPHOONS IN COASTAL WATERS AT JITIMEN IN ZHUJIANG RIVER ESTUARY

海洋对台风的响应对台风预报具有重要意义,但是由于动力结构比较复杂,近岸水体对台风的响应仍然不明确。基于珠江口海洋生态环境教育部野外科学观测研究站的1号浮标观测资料(2021年7~8月),分析了珠江口鸡啼门海域在台风“查帕卡”和“卢碧”期间海洋动力学和热力学响应特征。台风过境引起水体的纬向流速显著增强,“查帕卡”激发了强烈的顺时针近惯性振荡,“卢碧”则激发了接近惯性频率的逆时针海水运动。受当地浅水深的影响,近惯性能量在一个惯性周期(32 h)后快速耗散。两个台风引起的海表温度(sea surface temperature, SST)降温幅度均大于2.2℃,这种降温受潜热通量影响较大;同时,台风过后晚上的SST均大于白天的SST,这也是受到潜热通量的影响。

Understanding the oceanis response to typhoon is of great significance for typhoon forecasting.Due to the complexity of the dynamic structure,the response of coastal water to typhoon is still unclear.Based on observation data of a buoy(July—August 2021) deployed at Jitimen in Zhujiang(Pearl) River estuary,we analyzed the dynamical and thermodynamic responses of the ocean waters to typhoons Cempaka and Lubit passing the study areas during the observation.The two typhoons caused a significant increase in zonal velocity of water.Cempaka intensified remarkably the clockwise near-inertial oscillations,while Lupit motivated the counterclockwise seawater motion that close to inertial frequency.Affected by the local shallow water,the near-inertia kinetic energy dissipated rapidly after an inertial cycle in 32hours.The cooling amplitude of sea surface temperature(SST) caused by the two typhoons was greater than 2.2 ℃,which was apparently affected by latent heat flux.At the same time,the SST during the night was higher than that during the day after typhoon passing,which was also influenced by latent heat flux.