Spatio-temporal property changes of the Atlantic water in the Chukchi sea

초록

The Korean icebreaking research vessel Araon has made an effort to monitor water property changes around the Chukchi Sea and Chukchi Borderland every summer from 2010. Using the 8-year hydrocast profiles we investigate spatial and temporal property changes of the Atlantic Water, typically located around 300-800 m under the Pacific Winter Water. Our special focus is on density inversions that seem to be caused by thermohaline double diffusive intrusions. We calculate dissipation rate and vertical eddy diffusivity by calculating Thorpe scales using the hydrocast profiles based on Osborn (1980) and Shih et al. (2005) methods. Evidence of enhanced ocean mixings associated with large Thorpe scales exhibits significant spatial and temporal variabilities with some vertical eddy diffusivity values larger than 10 m s around the Mendeleev and Northwind ridges, one order larger than the average over a global ocean. We relate the double-diffusion-induced Atlantic Water property changes with changes of wind fields, sea-ice coverage, bottom topography and Atlantic source water input.