Nearfield measurements of ice melting noise in the central Arctic Ocean in summer

• Published in: Polar Science
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Ice melting noise; Bubble clouds; Air temperature; Summer; Central arctic ocean; Arctic; Arctic Ocean; Polar Science; Sea ice
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=16019; http://id.nii.ac.jp/1291/00015907/

Sea ice melting is very common in Arctic summer, so it is important to study ice melting noise. This paper analyzes a 456 min time series of under-ice noise that was recorded at a depth of 29.9 m in the central Arctic Ocean when the area was approximately 89% ice cover, UTC time, on August 8th, 2017. When the air temperature was higher than the freezing point of the surface sea water, the under-ice noise levels increased. In particular, the noise levels at 80–240 Hz and 380–660 Hz had two broad peaks and increased by 5–15 dB, furthermore, there was a large number of transient signals in the noise data. When the air temperature decreased and was less than the freezing point of the surface sea water, the under-ice noise levels gradually decreased, the broad peaks of the under-ice noise levels gradually disappeared, and the transient signals also disappeared. At the above two frequency bands, the correlation coefficients between the air temperature and under-ice noise levels were generally above 0.5 and reached a maximum value of 0.81. These results suggest that the changes in the under-ice noise levels could be attributed to sea ice melting.