Extracting tidal variability of sea ice concentration from AMSR-E passive microwave single-swath data: A case study of the Ross Sea

Abstract

The periodic divergence of stress applied by ocean tidal currents to sea ice affects the time-averaged ice concentration (C ice) and heat and freshwater fluxes at the ocean surface. We demonstrate that, at sufficiently high latitudes, tidal variability in C ice can be extracted from single-swath data from the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) satellite passive microwave sensor, although time intervals between swaths are irregular. For the northwest Ross Sea where tidal currents are large, tidal divergence is the dominant cause of C ice variability in winter, with a range of ±0.2 about a mean of ~0.8. Daily-averaged C ice values vary from >0.9 at neap tides to ~0.7 at spring tides. Variability at the fundamental tidal periods is about half that expected from an inverse barotropic tide model for the Ross Sea, suggesting that the measured tidal signal in C ice may be used to diagnose sea ice mechanical properties and ice/ocean coupling. Key Points We can extract tidal signals in sea ice concentration from satellite data Tides are the largest signal in sea ice concentration in the northern Ross Sea Measured tidal divergence is a test of ice mechanics and ocean/ice interactions ©2013. American Geophysical Union. All Rights Reserved.