Arctic ice cap characteristics (rectangle indicates the study area). (a) Sea-ice concentrations during its minimum extent in September 2005. (b) Sea-ice concentrations during its maximum extent in March 2006. (c) Ice thickness in October/November 2005, showing accumulation of multi-year ice along the Canadian archipelago. (d) Ice thickness during the winter (February/March 2006), showing its extension west, up to the Alaskan coast. (e) Arctic Ocean dominant current structure, showing the Beaufort Gyre (BG) and the transpolar drift (TPD), and an example of the ice-drift vector fields on December 26, 2005. Data are from the NSIDC.
(Color online) Map of the study area, showing the bathymetry and the locations of the recording station in the Amundsen Gulf and the coastal weather stations of Cape Parry and Sachs Harbor.
Annual spectrograms of hourly spectral levels of (a) total ocean noise; (b) ANL; and (c) their ratio. (d) Percentiles of hourly spectral levels of the under-ice ANL, from November 6, 2005, to June 23, 2006. Black pixels in (a), (b), and (c) correspond to time-frequency bins affected by strum; white pixels correspond to bins with levels below the instrument floor in (a) and (b), and to a ratio of 1 (0 dB) in (c).
Time-series (daily medians) of the environmental variables and the under-ice [10–500 Hz] ANL at the mouth of the Amundsen Gulf in winter 2005–2006. (a) Local ice concentration (100-km radius around the recording station). (b) Air temperature. (c) Air pressure. (d) Wind speed. (e) Ice-drift speed in the Amundsen Gulf (solid line) and in the multi-year ice plume off the Gulf (dashed line). (f) In situ current speed, showing the immediate under-ice current (solid line) and the ∼50 m depth current (dashed line). (g)Broadband sound pressure level of the [10–500 Hz] ANL.
PSDs of the hourly time-series presented in Fig. 4 . (a) Air pressure. (b) Wind speed. (c) Currents at 11 m. (d) Broadband sound pressure level of the [10–500 Hz] ANL.
Proportion of time (bars) and corresponding mean speed (lines) as functions of the direction the mean hourly wind is blowing to (a) and the ice drift within 100-km radius of the recording station (b), for the period of November 6, 2005, to June 23, 2006, as shown in Fig. 4 .
Scatter plot of the PCA factor scores in the spaces of the first two principal components, along with the factor loadings for each environmental variable. Color scale indicates the daily median under-ice [10–500 Hz] ANL. Larger dots represent several points. Ice Con., ice concentration; P, air pressure; ISNS, ice speed north-south component, with northwards positive; ISEW, ice speed east-west component, with eastwards positive; ISEP, ice speed; W, wind speed; CSurf, current speed at 11 m; CAural, current speed at 51 m; T, air temperature.
Maps of the correlations (Pearson r) between the daily under-ice [10–500 Hz] ANL and Arctic ice-drift magnitudes. The correlations are shown for different percentiles of the daily CDFs of the hourly [10–500 Hz] ANL. (a) 10th percentile. (b) 25th percentile. (c) 50th percentile. (d) 75th percentile.
Map of correlations (Pearson r) between the ice drift time-series at the location of maximum correlation in Fig. 8 and the ice-drift time-series at other nodes of the ice-drift grid, showing the large-scale continuity in the regional ice drift.
(Color online) Schematic representation of the ocean-noise propagation from the multi-year ice plume that is drifting westerly from offshore Beaufort Sea to the 50-m deep recording location on the shelf in the Amundsen Gulf.
Periods corresponding to significant peaks in the spectra of the hourly time-series of under-ice [10–500 Hz] ANL and environmental variables, with their interpretation.
Pearson correlations between under-ice [10–500 Hz] ANL and daily median and environmental variables. Underlined: p < 0.05; bold: r 2 ≥ 0.10.
Article metrics loading...
Full text loading...