南海北部相干内潮和非相干内潮演变特征

Evolution characteristics of coherent and incoherent internal tides in the northern South China Sea

通过南海北部跨越陆坡和陆架区的3套潜标数据,对全日和半日相干、非相干内潮的动能变化特征进行了研究。研究表明,全日内潮沿陆坡区向陆架区传播的过程中,在陆坡区主要以全日相干内潮生成为主,平均动能生成率为2.32J/(m^3·s);在陆架区以全日相干内潮耗散为主,平均动能耗散率为0.44J/(m^3·s)。全日非相干内潮动能在陆坡和陆架区均增长,平均动能生成率分别为0.39J/(m^3·s)和0.03J/(m^3·s)。全日与半日相干内潮动能在陆坡和陆架区的表现不同,陆坡区的全日相干内潮动能明显大于陆架区的全日相干内潮动能,而半日相干内潮动能在陆坡和陆架区没有明显差别;陆架区的全日和半日非相干内潮动能要大于陆坡区的全日和半日非相干内潮动能。

Three sets of mooring Acoustic Doppler Current Profiler（ADCP）data across the continental slope and shelf area in the northern South China Sea are used to study the kinetic energy characteristics of diurnal and semidiurnal coherent and incoherent internal tides（ITs）.Research shows that when diurnal ITs spread along continental slope and continental shelf,it is dominated by diurnal coherent ITs kinetic energy generation in the continental slope and the average diurnal coherent ITs kinetic energy generation rate is 2.32 J/（m^3·s）.It is dominated by diurnal coherent ITs kinetic energy dissipation in the continental shelf and the average diurnal coherent ITs kinetic energy dissipation rate is 0.44 J/（m^3·s）.The kinetic energy of diurnal incoherent ITs increases in both the continental slope and the continental shelf and the average diurnal incoherent ITs kinetic energy generation rate are 0.39 and 0.03 J/（m^3·s）.The kinetic energy characteristics of diurnal and semidiurnal coherent ITs are different in the continental slope and continental shelf.It showed that the kinetic energy of diurnal coherent ITs in the continental slope is significantly greater than the kinetic energy of diurnal coherent ITs in the continental shelf,but the kinetic energy of semidiurnal coherent ITs energy had no significant difference in the continental slope and continental shelf.The kinetic energy of diurnal and semidiurnal incoherent ITs in the continental shelf is greater than that in the continental slope.