Acoustic observation of ice rifting and breaking events on the Antarctic ice shelf using remote hydroacoustic listening stations
Long-term continuous monitoring of ice break-up on ice shelves and icebergs in Antarctica is essential for a global observation system of climate change and its consequences. While calving of massive pieces of ice from the Antarctic ice shelf is well observed from satellites, numerous ice breaks of...
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| Format: | Thesis |
| Language: | English |
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Curtin University
2010
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| Online Access: | https://hdl.handle.net/20.500.11937/2616 |
| Summary: | Long-term continuous monitoring of ice break-up on ice shelves and icebergs in Antarctica is essential for a global observation system of climate change and its consequences. While calving of massive pieces of ice from the Antarctic ice shelf is well observed from satellites, numerous ice breaks of smaller volume cannot be systematically monitored and statistically analysed by the existing means of remote sensing and local in-situ observations. This study aimed to investigate the feasibility of an alternative monitoring approach based on remote acoustic observations of ice rifting and breaking events on Antarctic ice shelves and icebergs using distant underwater acoustic listening stations in the ocean. This investigation was carried out using long-term continuous sea noise recordings made from 2002 to 2007 at two hydroacoustic stations deployed in the Indian Ocean as part of the International Monitoring System of the Comprehensive Nuclear-Test-Ban Treaty: off Cape Leeuwin in Western Australia (HA01) and off Chagos Archipelago (HA08).Investigations of a number of scientific and technical issues relevant to the main objective were carried out in this study. They include: 1) processing of the CTBT hydroacoustic data from the two IMS stations with the aim of detecting and identifying signals received from Antarctic ice breaking events; 2) investigating the time-frequency arrival structure of the signals expected from ice events using experimental data and numerical modelling of acoustic propagation from Antarctica to the IMS stations in the Indian Ocean; 3) analysing the bearing accuracy of the IMS stations; 4) examining three different schemes for localization of ice events using either one or two IMS stations; 5) analysing the spatial distribution of Antarctic ice events observed over 6 years of data collection and its correlation with the major glacial features of the Eastern Antarctic coastal zone which are most likely sources of newly calved icebergs and underwater noise produced by ice breakup; 6) analysing ... |
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