基于Argo资料的热带印度洋上层声场分析

为了解热带印度洋的水声场,利用2004-2013年10a的地转海洋学实时观测阵(Argo)资料,根据声速计算经验公式,对水声的水平分布、铅直断面分布、声跃层的分布、季节变化和铅直结构进行了较为全面的分析,并对强跃层区进行逐月研究。结果表明,50m深度层声速场呈北高南低的纬向带状分布形式,而200m深度层声速场由北向南呈现高—低—高—低分布;在85°E断面上,声速等值线在赤道以南存在较大的槽、脊,而在赤道以北较为平直;声跃层的深度冬季总体分布为南浅北深,夏季在10°N西印度洋和10°S东印度洋各有一部分明显的较深区域;跃层厚度普遍冬季大于夏季,东部大于西部,跃层强度的分布在冬季存在1个高值区,在夏季存在2个高值区;跃层的断面分布上,其结构、强度和位置都随季节有明显变化。

Analysis of acoustic field in tropical Indian Ocean upper based on Argo data

For an in-depth knowledge of the underwater acoustic field in the tropical Indian Ocean, a relatively comprehensive research and analysis is made, including the horizontal distribution and vertical cross-section distribution of underwater sound, the distribution of acoustic spring layer, the seasonal variation and the vertical structure by the use of the Argo (Array for Real-time Geostrophic Oceanography)data from 2004 to 2013 and in accordance with the empirical formula offered by Chen and Millero for sound velocity calculation. In addition, the strong spring layer was researched month by month. The result shows that the 50-meter-deep acoustic velocity field distributs in annuluses broadwise, high in the north and low in the south, while the 200-meter-deep acoustic velocity field distributes in the form of upland-bottomland-upland-bottomland from north to south. On the fracture surface at 85°E, there are larger trough and ridge for acoustic velocity isogram to the south of the equator while there is flat and straight land to the north; and acoustic spring layer generally distributes shallowly in south and deeply in north in winter. There are some visible deep regions in the Western Indian Ocean at 10°N and the Eastern Indian Ocean at 10°S. The thickness of spring layer is usually larger in winter than in summer and larger in the east than in the west, and there is a high value area for the distribution of the layer intensity in winter and two high value areas in summer. About the cross-section distribution of the layer, its structure, intensity and position change significantly from season to season.