TY - JOUR T1 - Freshwater input and vertical mixing in the Canada Basin’s seasonal halocline: 1975 versus 2006-2012 A1 - Rosenblum,Erica A1 - Stroeve,Julienne A1 - Gille,Sarah T A1 - Tremblay,L Bruno A1 - Lique,Camille A1 - Fajber,Robert A1 - Galley,Ryan A1 - Barber,David A1 - Loureiro,Thiago A1 - Lukovich,Jennifer AD - Centre for Earth Observation Science, University of Manitoba, Winnipeg, Manitoba, Canada AD - Department of Atmospheric Science, McGill University, Montreal, Quebec, Canada AD - Centre for Polar Observation and Modelling, University College London, Earth Sciences, London, United Kingdom AD - National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA AD - Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA AD - University of Brest, CNRS, IRD, Ifremer, Laboratoire d‘Oceanographie Physique et Spatiale (LOPS), IUEM, Brest, France AD - Department of Physics, University of Toronto, Toronto, Ontario, Canada AD - Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada AD - Ryerson University, Toronto, Ontario, Canada UR - https://doi.org/10.1175/JPO-D-21-0116.1 DO - 10.1175/JPO-D-21-0116.1 KW - Ocean KW - Arctic KW - Ocean dynamics KW - Mixed layer KW - Seasonal variability KW - Multidecadal variability N2 - The seasonal halocline impacts the exchange of heat, energy, and nutrients between the surface and the deeper ocean, and it is changing in response to Arctic sea ice melt over the past several decades. Here, we assess seasonal halocline formation in 1975 and 2006-2012 by comparing daily, May to September, below-ice salinity profiles collected in the Canada Basin. We evaluate differences between the two time periods using a one-dimensional (1D) bulk model to quantify differences in freshwater input and vertical mixing. The 1D model metrics indicate that two separate factors contribute similarly to stronger stratification in 2006-2012 than in 1975: (1) larger surface freshwater input and (2) less vertical mixing of that freshwater. The first factor is mainly important in August-September, consistent with a longer melt season in recent years. The second factor is mainly important from June until mid-August, when similar levels of freshwater input in 1975 and 2006-2012 are mixed over a different depth range, resulting in different stratification. These results imply that decadal changes to ice-ocean dynamics, in addition to freshwater input, significantly contribute to the stronger seasonal stratification in 2006-2012 than in 1975. The findings highlight the need for near-surface process studies to elucidate the roles of lateral processes and ice-ocean momentum exchange on vertical mixing. Y1 - 2022/07 PB - American Meteorological Society JF - Journal Of Physical Oceanography SN - 0022-3670 VL - 52 IS - 7 SP - 1383 EP - 1396 ID - 86374 ER -