Relative Contribution of Seawater Physical Property to Seismic Reflection Coefficient
详细信息
- 责任者：Dong Chongzhi (Key Laboratory of Submarine Geosciences ; Second Institute of Oceanography ; Hangzhou 310012 ; China) ; Song Haibin
- 刊名：Chinese Journal of Geophysics
- 出版年：2013
- 卷期：56(6)
- 关键词：地震勘探 ; seismic exploration ; 海洋物探 ; marine geophysical exploration ; 反射系数 ; reflectance coefficient
- 页码：p.2123-2132
- 图表：8 illus., 1 table, 32 refs.
- 分类号：1600
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
The relation between seismic profile and seawater physical property is one of the key problems urgent to be studied in seismic oceanography. This paper choose three groups of CTD data, including the section of Meddy, ten stations at different latitudes of the oceans, monthly data in the northeastern South China Sea, to study the normal and non-normal relative contribution according to the sea area, season and depth of water. The results show that the average normal relative contributions of sound speed and temperature similarly vary with sea area, season and water depth in a range of 78%~94% and 74%~98% respectively, mainly determined by the physical differences between adjacent water masses. The non-normal relative contributions of sound speed and temperature are enhanced with the increasing incidence angle, but the relative contributions of density and salinity are opposite. The prestack seismic data for inversion should contain gathers with a wide range of incidence angles. It is especially important to contain seismic traces with small incidence angle to improve the accuracy of density and salinity inversion which have smaller relative contribution. Through comparing the relative contribution of Meddy with the Turner angle section, it is found that Turner angle has an excellent indicative function to relative contribution. The zone, where the relative contributions of density and salinity are larger, well corresponds to the boundary between double stable region and diffusive region, where Turner angle is about -45°. The density ratios are relatively small at high latitude stations which result in small relative contribution of sound speed and temperature. The relative contributions of sound speed and temperature are slightly larger in the surface seawater in the northeastern South China Sea. This may be caused by temperature difference and density ratio increasing due to the Kuroshio intrusion.