Underwater topographic survey with tide - free mode made with the digital deep sounding apparatus and the gpsrtk 相结合进行无验潮模式水下地形测量
2.
Semi - diurnal constituent is the dominant component tides in this area . the co - tidal and co - range charts show that neither semi - diurnal constituents nor diurnal constituents have tide - free points . only the shallow constituents m4 and ms4 respectively have three and two tide - free points 各分潮的潮汐同潮图表明：在本海域内，半日和全日分潮都没有出现无潮点，唯浅海分潮m _ 4和ms _ 4分别有三个和两个无潮点。
