粤西阳江海域春夏季沿岸激流现象及机理分析

Mechanism analysis of alongshore shock current phenomenon in Yangjiang sea area along the coast of western Guangdong in spring and summer

通过分析2018–2019年粤西阳江沿岸流海域多站点周年观测水文气象实测资料,发现2019年春季和夏季阳江沿岸流海域存在激流现象。研究结果表明:(1)2019年5月5日凌晨6时,观测站点2 m水深处流速达到164.7 cm/s,9 m水深处流速达到127.6 cm/s。2019年8月1日凌晨4时至5时,阳江沙扒海域2 m水深处流速达到161.8 cm/s,9 m水深处流速达到156.6 cm/s。(2)粤西沿岸流阳江20~30 m水深海域春夏季突发性强流具有典型的激流特征。激流在涨急时刻发生在海洋表层,持续2~4 h。(3)在西南风与东北风转换期间,粤西沿岸海域容易形成海水幅聚带,近岸海域海平面上升,外海海域海平面下降,强劲的自岸向外水平压强梯度力导致近岸海水加强向西运动,从而产生激流。

We can discover that there exist storm currents along Yangjiang sea area of western Guangdong waters in spring and summer of 2019 by analyzing materials which measure hydrologic and hydrometeorological along west coast of Guangdong flow Yangjiang sea area from 2018 to 2019. The result of research shows: Firstly, the velocity of 2 m water depth at the observation site reached 164.7 cm/s and 9 m water depth at the observation site reached 127.6 cm/s at 6:00 a.m. on May 5, 2019. The velocity of Yangjiang Shapa sea area 2 m water depth at the observation site reached 161.8 cm/s and 9 m water depth at the observation site reached 156.6 cm/s at 4:00 to 5:00a.m. on August 1, 2019. Secondly, the suddenly strong currents in spring and summer have typically shock current trait in the Yangjiang 20 m to 30 m sea area along the shore current area of western Guangdong. The strong current happens at the surface of the ocean during the time of rising tide for 2 h to 4 h. Thirdly, during the transition period of southwest wind and northeast wind, the coastal sea area of western Guangdong is prone to form a water convergence zone. The sea level of the coastal sea area rises, and the sea level of the offshore sea area drops. The strong horizontal pressure gradient force from the shore to the outside causes the coastal water to strengthen the westward movement, resulting in shock current.