ONR Graduate Traineeship Award: Multi-modal, near-shore, ice-covered Arctic acoustic propagation measurements and analysis

It is well known that the global climate change is affecting the Arctic ice layers [1-4]. In general, the ice layer formations are much different than those which were studied in early acoustic experiments. This changing Arctic environment warrants new investigation into the acoustic detection, identification, and tracking of anthropogenic sources. Because there is less ice in the Arctic environment for longer time periods during the year, there is expected to be increased near-shore anthropogenic activity. This activity may come in the form of Arctic shipping through the Northwest Passage, natural resource exploration, tourism, and both foreign and domestic military activity. It is of interest to determine the location and type of these anthropogenic sources for situational awareness in the ocean battlespace. Sensing of sources in the first-year shore-fast ice environment is non-trivial due to ice ridging and ever-changing ice movements. Furthermore, first-year, near-shore ice is not well understood in terms of acoustic properties. Therefore, new data are required to understand the acoustic transmission paths in the first-year, near-shore ice environment and to validate algorithms for detection, identification, and tracking of anthropogenic sources in shallow water (less than 50 m) with thin, irregular ice sheets.'The technical goals of this proposal are:1) To process the transmission loss (TL) and frequency response function (FRF) data for the first-year, shore-fast Arctic ice environment captured during field test in Barrow, AK, in April 2016.2) Generate and process new surrogate measurement data from ice-covered waters at Michigan Tech to help answer propagation path questions from the Arctic experiment.3) Create and test anthropogenic acoustic source localization and tracking methods using underwater and/or in-air vector sensors.The educational goal of this proposal is to support completion of the research started by DARPA. Miles Penhale, a Ph.D. candidate who has passed the proposal stage and is expected to finish his degree in summer 2019, will complete this research as part of the ONR Graduate Traineeship opportunity in Arctic Acoustics. The description of this effort can be located in R2 Sub-Activity Ocean Sciences in PE 0601153N.