Typhoon Wind Speed Estimation via Microseismic Noise Recorded by Submarine Optical-Fiber Distributed Acoustic Sensing

Sea surface wind speed (SSWS) is an essential parameter for typhoon monitoring and forecasting. However, in situ observations under typhoon conditions are rather rare. Distributed acoustic sensing (DAS) using optical-fiber (OF) cables has recently become widely employed to monitor sea states. This study proposes a method to estimate SSWS using a DAS-instrumented submarine OF cable. The microseismic noise generated by ocean surface gravity waves (OSGWs) during the passage of Typhoon Muifa (2022) over the OF cable serves as the input dataset. A mathematical model is developed to invert the SSWSs from the microseismic noise intensity and inferred OSGW energy. The inversion results yield a root mean square error of ∼1.76 m/s compared with simultaneous observations at a nearby ocean buoy. These findings demonstrate that DAS-instrumented cables can potentially be used to monitor SSWSs under typhoon conditions, thereby offering an interdisciplinary approach that complements traditional ocean- and satellite-based observations.