Novel Methods to Observe Heat and Ice in the High Latitudes Using PIES

该项目将开发和测试一种非传统方法，使用配备压力传感器的反向回声探测仪(PIE)测量高纬度海域、大陆架和峡湾的时变热含量和垂直温度分布。Pie安装在破坏性冰山龙骨下方的海底，是增进对峡湾动力学和陆架-峡湾相互作用的了解的一种有前途的廉价方式，并将加强对高纬度地区的长期监测能力，因为那里偏远和恶劣的条件阻碍了传统的现场观测技术。使用馅饼来描述高纬度的可变性是现有技术的一种新颖的再利用，但其原理与传统蓝水馅饼的使用原理相同：由于声速对温度的依赖，与馅饼与海-气界面之间的反射相关的从表面到底部的往返声波旅行时间是中间水柱中热含量的极好替代。此外，由于当冰存在时，海水-冰界面的反射也会被探测到，PIES还提供了一种手段来表征高纬度系统中的冰成分。和平研究所建议利用在格陵兰东部谢米利克峡湾进行为期一年的试验部署所收集的现有馅饼数据，以及在峡湾和附近大陆架进行为期两年的三个馅饼部署所收集的观测数据，来开发这些方法。

This project will develop and test a non-traditional method to measure the time-varying heat content and vertical temperature profile in high-latitude seas, shelves, and fjords using pressure-sensor-equipped inverted echo sounders (PIES). PIES, which are installed on the seafloor below the reach of destructive iceberg keels, present a promising and inexpensive way to improve understanding of fjord dynamics and shelf-fjord interactions and will increase long-term monitoring capabilities in high latitudes where remoteness and harsh conditions hamper traditional in situ observation techniques. The use of PIES to characterize variability at high latitudes is a novel repurposing of an existing technology, but rests on the same principle as the traditional blue-water uses for PIES: due to the dependence of sound speed on temperature, the surface-to-bottom round-trip acoustic-travel-time associated with reflections between the PIES and the air-sea interface is an excellent proxy for heat content in the intervening water column. Furthermore, since reflections from seawater-ice interfaces are also detected when ice is present, PIES also provide a means to characterize the ice component in high-latitude systems. The PIs propose to develop these methods with existing PIES data collected in a 1-year test deployment in Sermilik Fjord in eastern Greenland and with observations to be collected in a 2-year deployment of three PIES in the fjord and on the nearby shelf.