IMOS - ANMN Passive Acoustic Observatory at Perth Canyon, WA (PAPCA)

The Perth Canyon Passive Acoustic Observatory consists of two to four moorings fitted with hydrophones set on the seabed at 400-490 m depth that record noise in the ocean. This system can be used to monitor whale and fish migrations, seismic activity and other natural and man-made noise sources. If four moorings are set they are configured with a mooring at each apex of an approximate equilateral triangle of 5 km side with the fourth mooring in the triangle centre. Temperature loggers are set on each mooring at the seabed.

Each logger records at a sampling rate of 6 kHz for between 3-8 min of every 15 min. If four loggers are set a 22 kHz recording is also made once a day to allow accurate synchronisation of the instrument clocks. This is required for locating the source of a sound based on its time of arrival at each hydrophone in the array. A 7 kHz pinger set on the central mooring pings for 35 minutes at a 20 s interval once per day to overlap the 22 kHz sample.

Raw data from each logger is in the form of mixed binary/text files comprised of:
1) text header and footer containing recording start and end date/time, quality control and sampling configuration; and
2) sea noise data of 16 bit unsigned integer, binary values (IEEE, little endian).

Instruments are calibrated for system gain with white noise of known level input with the hydrophone in series, before and after deployments. System calibrations are made over 2 Hz to the Nyquist frequency. The instrument clock drift is checked against GPS transmitted UTC time before and after deployment.

The raw data can be obtained on portable disk from IMOS eMarine Information Infrastructure (eMII).

The Centre for Marine Science and Technology (CMST) at Curtin University has developed Matlab software to process and analyse these data.

This observatory was decommissioned in October 2017.

珀斯峡谷被动声学观测站（Perth Canyon Passive Acoustic Observatory）由2至4套锚系（mooring）组成，每套锚系搭载水听器（hydrophone）布设于400~490米深的海底，用于记录海洋噪声。该系统可用于监测鲸类与鱼类洄游、地震活动，以及其他自然与人为噪声源。若布设4套锚系，则在边长5公里的近似等边三角形的三个顶点各部署一套锚系，第四套锚系布设于三角形中心。每套锚系的海底位置均安装温度记录仪（temperature logger）。

每台记录仪的采样率为6 kHz，每15分钟内记录3至8分钟的数据。若部署4台记录仪，则每日额外进行一次22 kHz的采样，以实现各仪器时钟的精准同步——这一操作是基于声信号到达阵列中各水听器的时间差进行声源定位的必要前提。布放在中心锚系上的7 kHz脉冲发射器（pinger）每日以20秒的间隔持续发射35分钟，与22 kHz采样时段重合。

各记录仪的原始数据为混合二进制/文本文件，包含两部分内容：1）包含记录起止日期/时间、质控信息与采样配置的文本头与尾注；2）16位无符号整数格式的海洋噪声二进制数据（符合IEEE标准，小端序）。

仪器在部署前后均通过串联水听器输入已知幅值的白噪声完成系统增益校准。系统校准的频段覆盖2 Hz至奈奎斯特频率（Nyquist frequency）。仪器时钟漂移情况会在部署前后与GPS发送的UTC时间进行比对校正。

原始数据可通过IMOS海洋电子信息基础设施（eMarine Information Infrastructure, eMII）提供的便携式磁盘获取。

科廷大学（Curtin University）海洋科学与技术中心（Centre for Marine Science and Technology, CMST）开发了用于处理与分析该类数据的Matlab软件。

本观测站已于2017年10月退役。