内陆水域水下地形测量中声速改正方法探讨

Discussion on sound velocity correction for underwater topographic survey in inland waters

声速改正误差所引起的测深误差是影响测深精度的主要因素之一。通过对不同测深环境、不同声速改正模型的研究,提出了在几种典型测深环境下的声速改正方案。在长江中下游地区的施测结果表明,计算值和测量数据吻合性较好,采用间接法能够较好地满足该地区水下地形测量精度要求;在西藏惹雍错的施测结果表明,间接公式法计算的声速比实测值偏大,推荐采用直接法即通过声速剖面仪获取水体声速,或对水体水温分层观测,然后利用公式计算得出声速。在江河入海口水域,当采用直接法计算声速时,应考虑含盐量的影响。

Sounding error caused by sound velocity correction is one of major factors influencing sounding accuracy.By studying various sounding environment and models for sound velocity correction,a scheme is put forward under several typical sounding environments.The results from the survey conducted in the lower reaches of Yangtze River show that the calculated value matches the measured value,and the indirect method meets the accuracy requirement of underwater topographic survey in the area.The results obtained from survey in Reyong Lake,Tibet show that the sound velocity value calculated by indirect method is higher than measured value,thus a direct method by sound velocity profiler or formula method by observing stratified temperature are recommended;at the estuary of rivers,salinity should also be incorporated as an influencer when calculating sound velocity.