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The First Arrival Cycle Judgment Based Calculated Method for In Situ Acoustic Measurement of Attenuation in Water

The propagation loss of water is important in sediment acoustics and underwater acoustics. The propagation loss in water is analyzed theoretically and an in-situ acoustic instrument of Attenuation Array is used to measure attenuation of water. Based on the first arrival cycle (FAC) judgment method, point judgment based data analysis method (PJDAM) and cross correlation based data analysis method (CCDAM) have the similar results of attenuation as 20.89±4.67 dB/m and 22.43±7.37 dB/m respectively in a wide range of measurement frequency changing from 100 to 300 kHz, which is close to the theoretical calculation of 22.64 dB/m in water using the Attenuation Array. The analysis method will be useful in in-situ acoustic measurement of seafloor surficial sediment.