中文摘要：

本文首次提出了一套从反射地震数据提取反射强度、反射体倾角和反射体波动振幅等属性参数的方法,并将其应用到南海西南海域.计算结果进一步表明南海西南海域在夏季主要的海洋学现象为西南季风诱发的冷流.它首先在越南东部海域自南向北流动,然后在约12°N附近开始向东弥散.海表面表现为温度低异常和海面高度低异常;水体内部则表现为以温度低异常为特征的底层冷水上涌.同时,由于地震海洋学数据具有高横向分辨率和全海洋深度成像的优点,从计算结果中还可以识别出3个视宽度为~20 km的上升流区;其上涌的视幅度约为50~150 m,且在不同的深度具有各自的特点.我们的结果可以为南海西南海域夏季上升流的精细化、定量化研究提供必不可少的数据支持;这套方法在其他海域的扩展应用也有望成为研究海水垂向分布横向变化的有力工具.

英文摘要：

This paper first proposes a method to extract a reflection intensity,slope and fluctuation amplitude of a reflector from a seismic profile,and is applied to the seismic data acquired in the southwestern South China Sea. The results confirm that the main oceanographic phenomenon of the Southwestern South China Sea in summer is a cold current induced by the southwest monsoon. It first flows northward along the east coast of Vietnam, then diffuses eastward at around 12 ° N. It is manifested as a low temperature anomaly and a low height anomaly on the surface,and upwelling of deep water characterized by a low temperature anomaly inside the water column. Besides, due to the advantages of seismic oceanography in high lateral resolution and fast imaging of the full ocean depth, three upwelling zones can be recognized from calculation results with an apparent-width of ～ 20 km and apparent magnitudes of upwelling ranging from 50 m to 150 m. Upwelling zones represent varying characteristics at different depths. Our results can provide essential data support for refined and quantitative studies to the upwelling in the southwestern South China Sea in summer. Application of this method in other regions is also expected to become a powerful tool for studying the vertical distribution of lateral variations in seawater.