南海北部海底沉积物在温度变化下的三种声速类型

研究南海北部海底沉积物温度变化状态下声速性质,得出以下结论:(1) 南海北部海底沉积物具有声速温度正增长(STPIK)、声速温度负增长(STNIK)和声速温度波动(STWK)三种类型,后两种类型在世界其他范围内海域未见报道.(2) 声速温度正增长类型和声速温度负增长类型沉积物的温度变化对声速影响都具有十分显著的线性关系,但是原状样品由于组成不均匀性,增大了声速的非线性变化.(3)南海北部海底沉积物的孔隙度、密度等主要物理参数差异不明显,难以直接解释三类样品的温度-声速性质的不同.(4)对于STPIK类型沉积物,理论分析与实验结果的统一性,可以运用海底沉积物与海水声速比进行校正不同温度状态下的海底沉积物的声速.(5)对于STNIK和STWK类型沉积物,需要深入研究,从理论和实验角度揭开其机理和成因.海底沉积物声速-温度特性研究将为提高南海北部海域天然气水合物声学探测精度和准确度提供声速性质依据.

Three kinds of acoustic speeds of seafloor sediments in the northern South China Sea with temperature variation

The properties of acoustic speeds of seafloor sediments in varied temperature in the northern South China Sea were researched to draw some conclusions as follows:(1) there exist three kinds of sediments such as speed-temperature positive increase kind(STPIK),speed-temperature negative increase kind(STNIK),and speed-temperature waving kind(STWK).(2) According to the correlation analysis,speed and temperature of the STPIK and STNIK are in good linearity,while the nonlinearity of original samples is bigger than reconstructed ones because of their more inhomogeneous state.(3)The comparison of main physical parameters such as porosity and density is too weak to explain the difference of the three kinds.(4) The acoustic properties of STPIK are characterized by the accordance of theoretical and experimental research,and the speed ratio of sediment to sea water could be used to adjust the speed at different temperature.(5) The acoustic properties of STNIK and STWK need further study in theory and experiment.The study on the relationship of marine sediment sound speed with temperature will benefit the enhancement of the precision and accuracy of acoustic measurement in the northern South China Sea natural gas hydrate exploration.