Measurements of ocean currents, sea ice motion and ice draft have been made using upward looking sonar (ULS) datasets since 2008 for Shell in the Chukchi Sea. An Acoustic Doppler Current Profiler (ADCP) typically provides one to several minutes temporal resolution for currents and ice velocity and a 1 to 2 m vertical resolution for currents. An Ice Profiling Sonar (IPS) provides vertical resolution of better than 0.05 m for ice drafts and a temporal resolution of 1-2 seconds. Near ice boundary layer currents measurements are critical to understand the interaction between sea ice and the underlying ocean. These measurements allow for a better understanding of processes such as heat flux and ocean tracer mixing and thus they provide insight into the melting of sea ice from below and dispersion of oil and oil dispersants. Sea ice in the Chukchi Sea has a high degree of deformation, upwards of tens of metres, making the measurements of the near sea ice boundary currents challenging. ASL has developed semi-automated algorithms that accounts for the changing ice-canopy in order to measure these currents. Further algorithm development allows for the analysis of all valid current bins from the ADCP. By combining this analysis with ASL's standard ice velocity analysis, currents can be put into an ice-centric frame. These currents can be fitted to a law-of-the-wall logarithmic curve and thus ice roughness and turbulence parameters can be derived. Previous analysis has been completed for one of Shell's sites from the 2012-13 ice season (Mudge et al. 2014). Additional data sets and improved procedures allow for the modelling of drag coefficient from IPS derived roughness.
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