Monitoring ocean currents during the passage of Typhoon Muifa using optical-fiber distributed acoustic sensing

Jianmin Lin; Sunke Fang; Runjing He; Qunshu Tang; Fengzhong Qu; Baoshan Wang; Wen Xu

doi:10.1038/s41467-024-45412-x

Monitoring ocean currents during the passage of Typhoon Muifa using optical-fiber distributed acoustic sensing

Nat Commun. 2024 Feb 6;15(1):1111. doi: 10.1038/s41467-024-45412-x.

Authors

Jianmin Lin^{1

2}, Sunke Fang³, Runjing He³, Qunshu Tang^{3

4}, Fengzhong Qu^{3

4}, Baoshan Wang^{5

6}, Wen Xu^{7

8}

Affiliations

¹ Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province, Zhejiang University, Zhoushan, 316021, China. jmlin@zju.edu.cn.
² Donghai Laboratory, Zhoushan, 316021, China. jmlin@zju.edu.cn.
³ Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province, Zhejiang University, Zhoushan, 316021, China.
⁴ Donghai Laboratory, Zhoushan, 316021, China.
⁵ Deep Space Exploration Laboratory/School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China. bwgeo@ustc.edu.cn.
⁶ Mengcheng National Geophysical Observatory, University of Science and Technology of China, Hefei, 230026, China. bwgeo@ustc.edu.cn.
⁷ Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province, Zhejiang University, Zhoushan, 316021, China. wxu@zju.edu.cn.
⁸ Donghai Laboratory, Zhoushan, 316021, China. wxu@zju.edu.cn.

Abstract

In situ observations under typhoon conditions are sparse and limited. Distributed acoustic sensing (DAS) is an emerging technology that uses submarine optical-fiber (OF) cables to monitor the sea state. Here, we present DAS-based ocean current observations when a super typhoon passed overhead. The microseismic noise induced by ocean surface gravity waves (OSGWs) during Typhoon Muifa (2022) is observed in the ~0.08-0.38 Hz frequency band, with high-frequency (>0.3 Hz) component being tidally modulated. The OSGW propagation along the entire cable is successfully revealed via frequency-wavenumber analysis. Further, a method based on the current-induced Doppler shifts of DAS-recorded OSGW dispersions is proposed to calculate both speeds and directions of horizontal ocean currents. The measured current is consistent with the tidally induced sea-level fluctuations and sea-surface winds observed at a nearby ocean buoy. These observations demonstrate the feasibility of monitoring the ocean current under typhoon conditions using DAS-instrumented cables.

Abstract

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