標題：
AZFP profiler聲學浮游動物魚類剖面儀，Insights from Winter?2021–22 Using an Acoustic Zooplankton Fish Profiler
摘要：
Abstract—Improved understanding of the role of the ocean in moderating climate and sustaining complex food webs is required to support ocean stewardship and ocean protection goals being pursued through Indigenous-led initiatives across Canada’s coastlines. The traditional territorial waters of the Nunatsiavut in the Labrador Sea contain a rich and diverse marine ecosystem regulated by a combination of physical oceanography and the presence of seasonal sea ice cover, transported southward by wind and ocean currents. The Nunatsiavut Government operates a growing research program to understand and monitor this complex biophysical system to support effective environmental management. As part of this research program, they are now in the fifth year of monitoring over-winter ocean and sea ice conditions at an offshore site near Nain, Labrador. Measurements made at this site have included water temperature, salinity, dissolved oxygen, turbidity, currents, and ice drafts and velocities. Combining these measurements to understand the ocean’s role in moderating climate and complex food webs is an important step in support of Indigenous-led research initiatives and ocean stewardship across Canada’s coastlines. The Nunatsiavut Government has collaborated with ASL Environmental Sciences to further develop environmental mon itoring at this site by supporting the first-ever deployment of the new ASL instrument known as the AZFP-ice. The AZFP ice is designed to collect high temporal and spatial resolution measurements of ice draft and simultaneous biological obser vations from its calibrated (±1 dB) multifrequency acoustical sensors. The AZFP-ice is a calibrated, scientific, singlebeam echosounder. The AZFP-ice uses a narrow beam 417 kHz center frequency channel to obtain ice keel depth, similar to ASL’s Ice Profiling Sonar (IPS). Simultaneous biological observations are realized using three separate channels, collecting calibrated backscatter measurements at 125 kHz, 200 kHz, and 769 kHz center frequencies. Building on ASL’s experience with the Acoustic Zooplankton Fish Profiler (AZFP) sonar system, the AZFP-ice is designed to operate autonomously for up to 12 months at a time. The AZFP-ice also features an upgraded electronics package that allows up to 1 TB of data to be stored internally. Its endurance and its internal memory capacity allow for excellent temporal coverage and make the instrument well-suited for deployment in challenging environments. The (ex situ) factory calibration allows backscatter to be measured on an absolute scale, which facilitates downstream processing such as the so-called ‘dB differencing’ approach that is common in fisheries acoustics. This paper introduces the new AZFP-ice and showcases its capabilities as a tool for environmental monitoring. An IPS-5 was located near the AZFP-ice, allowing for a comparison of the observed ice characteristics. Preliminary analysis of the data collected during an over-winter deployment from 2021 to 2022 indicates that the AZFP-ice facilitates sea-ice characterization. Much of the over-winter period is dominated by landfast ice, and segments of ice from break-up to ice clearing are compared from the closely spaced AZFP-ice and IPS-5. During the period of landfast ice, the ice dynamics are simple as the ice responds to the thermodynamic forcing. Daylight hours are greatly reduced in the winter, but this environment does not experience 24-hour darkness, unlike high-latitude environments. While the ice may be motionless, the other AZFP-ice frequencies indicate that below the ice activity continues during this period of reduced daylight. In this paper, the AZFP-ice’s acoustical observations of the under-ice biology are presented and discussed as we review examples from this deployment. The AZFP-ice is shown to provide a unique combination of measurements in a single instrument, offering researchers a physical context (i.e. ice thickness) alongside biological data.
Index Terms—sonar, underwater acoustics, instrumentation, ice characteristics, plankton.
摘要：更好地了解海洋在調(diào)節(jié)氣候和維持復雜食物網(wǎng)方面的作用，以支持通過加拿大海岸線土著主導的倡議實現(xiàn)的海洋管理和海洋保護目標。拉布拉多海Nunatsiavut的傳統(tǒng)領海包含豐富多樣的海洋生態(tài)系統(tǒng)，受物理海洋學和季節(jié)性海冰覆蓋的共同調(diào)節(jié)，由風和洋流向南輸送。Nunatsiavut政府正在開展一項不斷發(fā)展的研究計劃，以了解和監(jiān)測這一復雜的生物物理系統(tǒng)，以支持有效的環(huán)境管理。作為這項研究計劃的一部分，他們現(xiàn)在已經(jīng)進入了在拉布拉多奈因附近的一個海上地點監(jiān)測冬季海洋和海冰狀況的第五年。在該地點進行的測量包括水溫、鹽度、溶解氧、濁度、水流、冰氣流和速度。將這些測量結(jié)果結(jié)合起來，了解海洋在調(diào)節(jié)氣候和復雜食物網(wǎng)中的作用，是支持加拿大海岸線土著主導的研究倡議和海洋管理的重要一步。
索引術語 sonar、水下聲學、儀器儀表、冰的特性、浮游生物、魚探儀、AZFP、IPS5 冰剖面儀
