Reciprocal sound transmission measurement of mean current and temperature variations in the central part (Aki-nada) of the Seto Inland Sea, Japan
Reciprocal sound transmission measurement of mean current and temperature variations in the central part (Aki-nada) of the Seto Inland Sea, Japan
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DOI：
10.1007/s10872-011-0016-5
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发表时间：
2011-04
影响因子：
2.3
通讯作者：
Yudi Adityawarman;A. Kaneko;K. Nakano;N. Taniguchi;K. Komai;Xinyu Guo;N. Gohda
中科院分区：
文献类型：
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作者：
Yudi Adityawarman;A. Kaneko;K. Nakano;N. Taniguchi;K. Komai;Xinyu Guo;N. Gohda
2010年3月至5月，在日本濑户内海中部（昭那田）连接本州岛和四国岛（分别为日本第一和第四大主要岛屿）的线路上进行了30公里范围的相互声传输实验，以测量海洋上的平均洋流和温度变化。将行时差数据转换为电流后，估计沿声传输线的距离平均电流的平均值和标准差为（3.8-4.4）±（1.7-1.8）cm/s，其中两周潮汐变化在±30 cm/s范围内。正的平均流意味着水流从西向东缓慢地流经昭南。根据标准声速公式，将平均传播时间或单向传播时间转换为声速，再将固定的盐度和深度值转换为温度，估算出距离平均声速。除了精确测量（精度为0.01°C）的半日潮和日潮变化和季节增温外，气温数据显示出7.0和21.1 d的周期性变化，这在Aki-nada以前从未观测到过。这项研究表明，声波互向传输是一种长期精确测量沿海和内海平均洋流和温度变化的有力技术。
A 30 km-range reciprocal sound transmission experiment was carried out on the line connecting Honshu and Shikoku (the first and fourth biggest main Japanese islands, respectively) in the central part (Aki-nada) of the Seto Inland Sea, Japan, during March–May 2010 to measure the mean current and temperature variations over the sea. The range-averaged current along the sound transmission line was estimated to have a mean and standard deviation of (3.8–4.4) ± (1.7–1.8) cm/s after converting the travel time difference data into currents, including a fortnightly tidal variation in the range of ±30 cm/s. The positive mean current implies slow water movement from the west to east through Aki-nada. The range-averaged speed of sound was estimated by converting from the mean travel time or one-way travel time into the speed of sound, and further converted into temperature for fixed values of salinity and depth, according to the standard speed of sound formula. Besides the precise measurement (to an accuracy of 0.01°C) of semidiurnal and diurnal tidal variations and seasonal warming, the temperature data showed periodic variations with periods of 7.0 and 21.1 days that had never been observed in Aki-nada before. This study suggests that reciprocal sound transmission is a powerful technique for the long-term accurate measurement of mean current and temperature variations in coastal and inland seas.