2015年6月南海北部陆坡气旋-反气旋涡对陆坡水文和环流影响的观测

利用2015年6月南海北部现场观测的水文数据,结合卫星高度计资料,分析了2015年6月13日—28日南海北部陆坡在气旋涡-反气旋涡的双涡结构影响下的水文和环流特征。结果表明,2015年6月南海北部陆坡调查海区表层50 m以浅盐度存在NE—SW向低盐区,表层盐度最小值低于32,这表明南海北部陆坡存在跨陆架海水输送。在观测期间,南海北部陆坡调查海区受气旋涡和反气旋涡双涡结构影响,使得南海北部陆坡表层100 m以浅存在跨陆坡流,流速最大值出现在两涡交汇区域。此外,通过潜标连续海流资料,发现南海北部陆坡环流呈现了“深入浅出”(100 m以深层为向岸的入侵、以浅层为离岸的出流)的“两层结构”。

Observed hydrographical features and circulation with influences of cyclonic-anticyclonic eddy-pair in the northern slope of the South China Sea during June 2015

Using in situ hydrographic measurements during June 2015 and satellite altimeter data provided by archiving validation and interpretation of satellite oceanographic data(AVISO), the hydrographical features and circulation with influences of cyclonic-anticyclonic eddy-pair in the northern slope of the South China Sea during June 2015 were studied. The results showed that the low-salinity water in northeast-southwest direction was found in the upper 50 m in the northern slope of the South China Sea during June 2015. The minimum surface salinity values were below 32, which indicated the presence of cross-slope transport in the northern slope of the South China Sea. Due to the existence of cyclonic-anticyclonic eddy-pair in the northern slope of the South China Sea during the observation, the cross-slope currents were found in the upper 100 m,of which the maximum velocity was observed in the intersection of two eddies. In addition, the circulation across the continental slope in the Northern South China Sea derived from the moored current measurements, presented two-layer structure: offshore flow in the upper 100 m and onshore flow beneath 100 m.