Seismic Ocean Thermometry Using CTBTO Hydrophones

被引:4
作者
Wu, Wenbo [1 ,2 ]
Shen, Zhichao [1 ,2 ]
Peng, Shirui [2 ]
Zhan, Zhongwen [2 ]
Callies, Joern [2 ]
机构
[1] Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA
[2] CALTECH, Pasadena, CA 91125 USA
基金
美国国家科学基金会;
关键词
T-wave; ocean temperature change; earthquake; CTBTO hydrophone; SEA-LEVEL; LEEUWIN CURRENT; TEMPORAL COHERENCE; SOUTHERN-OCEAN; EVENTS; DECADE; ARRAY; HEAT;
D O I
10.1029/2023JB026687
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Due to limited observational coverage, monitoring the warming of the global ocean, especially the deep ocean, remains a challenging sampling problem. Seismic ocean thermometry (SOT) complements existing point measurements by inferring large-scale averaged ocean temperature changes using the sound waves generated by submarine earthquakes, called T waves. We demonstrate here that Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) hydrophones can record T waves with a higher signal-to-noise ratio compared to a previously used land-based T-wave station. This allows us to use small earthquakes (magnitude <4.0), which occur much more frequently than large events, dramatically improving the resulting temporal resolution of SOT. We also find that the travel time changes of T waves at the land-based T-wave station and the CTBTO hydrophone show small but systematic differences, although the two stations are only about 20 km apart. We attribute this feature to their different acoustic mode components sampling different parts of the ocean. Applying SOT to two CTBTO hydrophones in the East Indian Ocean reveals signals from decadal warming, seasonal variations, and mesoscale eddies, some of which are missing or underestimated in previously available temperature reconstructions. This application demonstrates the great advantage of hydrophone stations for global SOT, especially in regions with a low seismicity level.
引用
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页数:19
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