CAJ | 학술논문

根据2014年在南中国海开展声学试验的定深爆炸宽带声信号数据进行海底地声参数反演．考虑到不同海底声参数对不同声场物理参数的敏感程度不同以及不同海底声参数对不同反演方法的敏感程度亦不同，综合应用2种反演方法得到不同底质声参数：（1）根据接收的直达波和海底反射波计算得到关注海域的海底反射系数进而反演得到海底声阻抗；（2）实验海区的海底地形为大陆坡，选取 Hamilton 总结的关于沉积物声速与沉积物密度关系的经验公式，结合沉积物声阻抗与沉积物声速、沉积物密度的关系，进而反演得到沉积物声速和沉积物密度．沉积物声学参数的取样测量是在实验室条件下进行的，温度为23℃，大气压1×105 Pa，由于沉积物孔隙海水是决定沉积物声速的关键且受温度压强变化的影响显著，本研究利用沉积物声速与孔隙海水声速的比值即使在温度压强变化的情况下较稳定的特点，可对沉积物声速在实验室条件和海底原位条件进行校正．校正到海底温度和压强后，反演结果与沉积物取样的实测结果和 Hamilton 总结的结果吻合得相当好：（1）声阻抗的反演结果为2.0656×105 g／（cm2·s），修正后的沉积物取样结果则为2.0460×105 g／（cm2·s），Hamilton 总结的结果为2.2380×105 g／（cm2·s）；（2）声速的反演结果为1482.6 m ／s，修正后的沉积物取样结果为1467.5 m ／s，Hamilton 总结的结果为1502.8 m ／s；（3）密度的反演结果为1.3932 g／cm3，沉积物取样结果为1.4000 g／cm3，Hamilton 总结的结果为1.4890 g／cm3．
근거2014년재남중국해개전성학시험적정심폭작관대성신호수거진행해저지성삼수반연．고필도불동해저성삼수대불동성장물리삼수적민감정도불동이급불동해저성삼수대불동반연방법적민감정도역불동，종합응용2충반연방법득도불동저질성삼수：（1）근거접수적직체파화해저반사파계산득도관주해역적해저반사계수진이반연득도해저성조항；（2）실험해구적해저지형위대륙파，선취 Hamilton 총결적관우침적물성속여침적물밀도관계적경험공식，결합침적물성조항여침적물성속、침적물밀도적관계，진이반연득도침적물성속화침적물밀도．침적물성학삼수적취양측량시재실험실조건하진행적，온도위23℃，대기압1×105 Pa，유우침적물공극해수시결정침적물성속적관건차수온도압강변화적영향현저，본연구이용침적물성속여공극해수성속적비치즉사재온도압강변화적정황하교은정적특점，가대침적물성속재실험실조건화해저원위조건진행교정．교정도해저온도화압강후，반연결과여침적물취양적실측결과화 Hamilton 총결적결과문합득상당호：（1）성조항적반연결과위2.0656×105 g／（cm2·s），수정후적침적물취양결과칙위2.0460×105 g／（cm2·s），Hamilton 총결적결과위2.2380×105 g／（cm2·s）；（2）성속적반연결과위1482.6 m ／s，수정후적침적물취양결과위1467.5 m ／s，Hamilton 총결적결과위1502.8 m ／s；（3）밀도적반연결과위1.3932 g／cm3，침적물취양결과위1.4000 g／cm3，Hamilton 총결적결과위1.4890 g／cm3．
This paper provides the geoacoustic inversion results used broadband data from underwater explosion at fixed depth in an Acoustics Experiment in the South China Sea,2014.Considering sensitivity differences of acous-tic parameters of sediments to physical parameters of sound field and geoacoustic inversion methods,2 approaches are used respectively for different acoustic parameters of sediments.Firstly,acoustic impedance can be achieved by vertical bottom reflective coefficients from sound reflected of sea bottom divided by directly arrived sound.Second-ly,sound velocity and density can also be achieved by combining Hamilton empirical equation to the relationship between acoustic impedance,sound velocity and density of sediments.The Hamilton empirical equation is about sound velocity and density of sediments and another key is to choose appropriate terrain which is continental terrace in this experiment.On different sea bottom,acoustic parameters of sediment samples are measured in laboratory conditions of temperature 23℃ and standard atmospheric pressure 1-atm.As a result,acoustic parameters especial-ly sound velocity need to be corrected to match different temperatures and pressures.Sound velocity is corrected successfully,in this paper,due to the fact that porewater of sediment critically determines sound velocity and the ratio of the sediment sound velocity to the porewater sound velocity is relatively stable even in the conditions that the temperature and pressure varies greatly.Inversion results appear to be well consistent when compared with in situ gravity core measurements and with data from Hamilton.In detail,in terms of acoustic impedance,the gravity core result after correction and the Hamilton conclusion are 2.065 6 ×105 ,2.046 0 ×105 and 2.238 0 ×105 g/(cm2 ·s), respectively.In terms of sound velocity,the gravity core result after correction and the Hamilton conclusion are 1 482.6,1 467.5 and 1 502.8m /s,respectively.In terms of sediment density,the gravity core result after correc-tion and the Hamilton conclusion are 1.393 2,1.400 0 and 1.489 0 g/cm3 ,respectively.