Long-term underwater acoustic recordings 2013-2021

This dataset contains long-term underwater acoustic recordings made under Australian Antarctic Science Projects 4101 and 4102, and the International Whaling Commission’s Southern Ocean Research Partnership (IWC-SORP) Southern Ocean Hydrophone Network (SOHN). Calibrated measurements of sound pressure were made at several sites across several years using custom moored acoustic recorders (MARs) designed and manufactured by the Science Technical Support group of the Australian Antarctic Division. These moored acoustic recorders were designed to operate for year-long, deep-water, Antarctic deployments. Each moored acoustic recorder included a factory calibrated HTI 90-U hydrophone and workshop-calibrated frontend electronics (hydrophone preamplifier, bandpass filter, and analog-digital converter), and used solid state digital storage (SDHC) to reduce power consumption and mechanical self-noise (e.g. from hard-drives with motors and rotating disks). Electronics were placed in a glass instrumentation sphere rated to a depth of 6000 m, and the sphere was attached to a short mooring with nylon straps to decouple recorder and hydrophone from sea-bed. The hydrophone was mounted above the glass sphere with elastic connections to the mooring frame to reduce mechanical self-noise from movement of the hydrophone. The target noise floor of each recorder was below that expected for a quiet ocean at sea state zero. The analog-digital converter, based on an AD7683B chip, provides 100 dB of spurious free dynamic range, but a total signal-to-noise and distortion of 86 dB which yields 14 effective bits of dynamic range at a 1 kHz input frequency. The data for each recording site comprise a folder of 16-bit WAV audio files recorded at a nominal sample rate of 12 kHz. The names of each WAV file correspond to a deployment code followed by the start time (in UTC) of the file as determined by the microprocessor’s real-time clock e.g. 201_2013-12-25_13-00-00.wav would correspond to a wav file with deployment code 201 that starts at 1 pm on December 25th 2013 (UTC). Recording locations were chosen to correspond to sites used during AAS Project 2683. These sites were along the resupply routes for Australia’s Antarctic stations, and typically there was only one opportunity to recover and redeploy MARs each year.

本数据集收录了由澳大利亚南极科学项目4101、4102，以及国际捕鲸委员会南大洋研究伙伴关系（International Whaling Commission’s Southern Ocean Research Partnership, IWC-SORP）下属南大洋水听器网络（Southern Ocean Hydrophone Network, SOHN）采集的长期水下声学录音。
澳大利亚南极署（Australian Antarctic Division）科学技术支持小组设计并制造了定制系泊声学记录仪（MARs），研究团队使用该设备于多年间在多个观测站点完成了经校准的声压测量。
此类系泊声学记录仪专为南极深水环境下的年度长期部署设计。每台记录仪均搭载经工厂校准的HTI 90-U型水听器，以及经车间校准的前端电子系统（含水听器前置放大器、带通滤波器与模数转换器），并采用固态数字存储（SDHC卡）以降低功耗与机械自噪声（例如带电机和旋转盘的硬盘所产生的噪声）。
电子系统被封装于额定深度达6000米的玻璃仪器舱内，该舱通过尼龙绑带连接至短系泊缆，以实现记录仪、水听器与海床之间的解耦。
水听器通过弹性连接件安装于玻璃舱上方的系泊框架上，以此降低水听器运动产生的机械自噪声。每台记录仪的目标本底噪声低于海况0级时的安静海洋本底噪声水平。
该记录仪配备的模数转换器基于AD7683B芯片设计，具备100 dB的无杂散动态范围，总信噪比与失真度为86 dB，在1 kHz输入频率下可实现14有效位的动态范围。
每个观测站点的数据存储为一个文件夹，内含以标称采样率12 kHz录制的16位WAV音频文件。每个WAV文件的文件名由部署代码与该文件的UTC起始时间（由微处理器实时时钟生成）组成，例如201_2013-12-25_13-00-00.wav即代表部署代码为201、于2013年12月25日13时（UTC）开始录制的音频文件。
本次录音站点的选择对应于澳大利亚南极科学项目（Australian Antarctic Science, AAS）2683所使用的站点，这些站点沿澳大利亚南极科考站的补给航线分布，且每年通常仅有一次回收并重新部署MARs记录仪的机会。