• 主题
高级搜索  >
历史搜索 清空历史
首页> 美国政府科技报告 >Assessment of Hydroacoustic Propagation Using Autonomous Hydrophones in the Scotia Sea.
【24h】

Assessment of Hydroacoustic Propagation Using Autonomous Hydrophones in the Scotia Sea.

机译：利用斯科舍海自主水声对水声传播的评估。

获取原文
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The remote area of the Atlantic Ocean near the Antarctic Peninsula and the South Scotia Sea is a region where acoustic surveillance by International Monitoring System hydrophones is at best limited. Sound originating in this area is either blocked or hindered by the South Georgia, South Sandwich Islands and the associated seafloor ridge system, making the region a potential hydroacoustic blind spot. To investigate the sound propagation and interferences affected by these landmasses in the vicinity of the Antarctic polar front, an array of autonomous hydrophones (AUHs) was deployed in the Scotia Sea in December 2007. In January 2009, five AUHs were recovered, completing a 13-month-long acoustic monitoring operation. Four of the recovered instruments continuously recorded low-frequency acoustic signals (1:110 Hz) at a sampling rate of 250 Hz, with one instrument sampling at a rate a rate of 1000 Hz (1:440 Hz band-passed). The submerged moorings utilized autonomous crystal oscillator clocks, with small time shifts that average approximately 2 seconds per year. Despite the fact that the high-latitude ocean lacks a deep sound channel, low-frequency sound tends to travel relatively efficiently. Regional seismo-acoustic signals (bottom sources) and episodic tremors from large icebergs (near-surface sources) were utilized as natural sound sources. Surface sound sources, e.g., ice-related events, tend to suffer less transmission loss (TL) and dominate the background noise as a result of surface duct transmission and less interaction with seafloor features. On the other hand, earthquake-generated signals (bottom sources) interact more strongly with the shallow arc, and TL tends to be larger. The RAM PE-code (Collins, 1993a,b) was used to model TL, and the AUH data were used to compare with these modeling results. Both the observational and model results indicate a unique acoustic environment of the Scotia Sea, including the evidences of reflected T-waves by the steep slope of the South Georgia Island and efficient P-to-T conversion by the Scotia Ridge system. We found that transmission loss for the shallow-depth sources tends to follow an approximately 171og10(r) loss model at ranges of 10s to 100s km. Seafloor sources are characterized by greater TL, and where the range-dependent bathymetry shallows, the results deviate strongly from a simple log10(r) relationship. We present two-dimensional path-dependent TL models relative to the hydrophone receivers for near-surface and bottom sources.

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号