LONG-RANGE REVERBERATION AND BOTTOM SCATTERING STRENGTH IN SHALLOW WATER

According to the method of angular power spectrum for averaged sound field in shallow water,the transformation relation between arbitrary angle dependence of hottom scattering and the rangedependence of long-range reverberation in shallow water homogeneous layer is established.Ascompared with the conventional model of boundary reverberation at short range in deep sea,a multipath correction factor is added.By using the transformation relation,the bottombackscattering strength for the frequency band of 0.8—4.0kHz and grazing angle range of 2—10°has been derived from shallow-water reverberation data at five locations in the Yellow Sea,theBobai Sea and the East China Sea.It is shown that the bottom scattering constant(μ)and theangle index(2n)for high speed sediment of the continental shelf depend not only on sea area andfrqucncy,but also on angle range.     

浅海远程混响与海底散射强度

利用浅海平均声场角度谱分析法,在海底散射的任意角度关系和浅海均匀层远程混响的距离关系之间建立了变换关系。与国外沿用的深海近程界面混响理论相比,多了多途传播修正因子K(公式18)。利用该变换关系式,由黄海、渤海、东海等5个海区的浅海远程混响资料,推得频率为0.8—4kHz,掠射角为2—10°的低频、小掠角海底散射强度。所得结果与国外深海直接测量的大掠角数据衔接较好。结果同时表明,大陆架高声速海底散射常数(μ)和角度指数(2n)不仅与海区、频率有关,而且与角度范围有关。在掠角很小时,海底散射强度随掠角减小比中等掠角时衰减更快。     

中国科学院声学研究所成立卅周年

1994年7月1日，声学所度过了自己卅周岁的生日．中科院老一辈领导严济慈、郁文，中科院周光召院长、国家科委惠永正副主任及国防科工委、中船总、海军等80余位来宾出席了声学所建所卅周年庆祝会．会上，侯自强所长做了题为“面向甘一世纪的声学所”的报告，周光召院长、惠永正副主任，以及中科院院士汪德昭、马大酞、应崇福等做了重要讲话．侯自强所长的报告，从声学所的实际出发，面对声学发展和信息产业革命，把声场声信息研究和数字信号处理研究确定为声学所的两个研究方向．前者重点是水声物理和海洋声学、非线性声学、有源治声、检测超…