PIESs and Seaglider SG628 data for ISWs in the northern SCS

The dataset consisting of two PIESs and one Seaglider collected acoustic travel time, bottom, and hydrography data is used in the article entitled "Anatomy of mode-1 internal solitary waves derived from Seaglider observations in the northern South China Sea". Observations from a Seaglider, two pressure sensor-equipped inverted echo sounders (PIESs), and a thermistor chain (T-chain) mooring were used to determine the waveform and timing of internal solitary waves (ISWs) over the continental slope east of Dongsha Atoll. The Korteweg-De Vries (KdV) and Dubreil-Jacotin-Long (DJL) equations supplemented the data from repeated profiling by the glider at a fixed position (depth ~1017 m) during 19–24 May 2019. The glider recorded pressure perturbations were used to compute the rarely-measured vertical velocity (w) with a static glider flight model. After removing the internal tide-caused vertical velocity, the w of the eight mode-1 ISWs ranged from –0.35 to 0.36 m s–1 with an uncertainty of ±0.005 m s–1 due to turbulent oscillations and measurement error. The horizontal velocity profiles, wave speeds, and amplitudes of the eight ISWs were further derived from the KdV and DJL equations using the glider-observed w and potential density profiles. The mean speed of the corresponding ISW from the PIES deployed at ~2000 m depth to the T-chain moored at 500 m depth and the 19°C isotherm displacement computed from the T-chain were used to validate the waveform derived from KdV and DJL. The validation suggests that the DJL equation provides reasonably representative wave speed and amplitude for the eight ISWs compared to the KdV equation. Stand-alone glider data provides near real-time hydrography and vertical velocities for mode-1 ISWs and is useful for characterizing the anatomy of ISWs and validating numerical simulations of these waves.

本数据集由两台带压力传感器的倒置回声测深仪（pressure sensor-equipped inverted echo sounders，缩写PIES）与一台海洋滑翔机（Seaglider）采集的声传播时间、海底与水文数据组成，被应用于题为《南海北部基于海洋滑翔机观测的第一模态内孤立波特征解析》的论文中。研究利用海洋滑翔机、两台带压力传感器的倒置回声测深仪（PIES）以及热敏电阻链锚系（thermistor chain mooring，T-chain）的观测数据，解析了东沙环礁以东大陆坡区域内孤立波（internal solitary waves，ISWs）的波形与传播时刻。2019年5月19日至24日期间，滑翔机在固定位置（水深约1017米）开展重复剖面观测，其数据辅以Korteweg-De Vries（KdV）方程与Dubreil-Jacotin-Long（DJL）方程开展分析。研究人员通过静态滑翔机飞行模型，利用滑翔机记录的压力扰动数据计算了鲜有观测的垂直速度（w）。在去除由内潮引起的垂直速度后，8个第一模态内孤立波的垂直速度w介于-0.35至0.36 m·s⁻¹之间，受湍流振荡与测量误差影响，其不确定度为±0.005 m·s⁻¹。基于滑翔机观测得到的垂直速度w与位势密度剖面，结合KdV与DJL方程，研究人员进一步推导得到8个内孤立波的水平速度剖面、波速与波幅。以部署于约2000米水深的PIES至锚泊于500米水深的T-chain之间的内孤立波平均传播速度，以及由T-chain计算得到的19℃等温线位移，对KdV与DJL方程推导得到的波形进行验证。验证结果表明，相较于KdV方程，DJL方程能够更合理地反映这8个内孤立波的波速与波幅特征。单台海洋滑翔机即可为第一模态内孤立波提供近实时的水文与垂直速度数据，该数据集可用于解析内孤立波的结构特征，并验证此类波浪的数值模拟结果。