TY - JOUR

T1 - Turbulent mixing and the formation of an intermediate nepheloid layer above the Siberian continental shelf break

AU - Shultz, Kirsten

AU - Buttner, Stefan

AU - Rogge, Andreas

AU - Janout, M.A.

AU - Holemann, J.

AU - Rippeth, Tom

PY - 2021/5/16

Y1 - 2021/5/16

N2 - Intermediate nepheloid layers (INLs) form important pathways for the cross-slope transport and subsequent vertical export of particulate matter, including carbon. While intermediate maxima in particle settling fluxes have been reported in the Eurasian Basin of the Arctic Ocean, direct observations of turbid INLs above the surrounding continental slope are still lacking. In this study, we provide the first direct evidence of a turbid INL, coinciding with enhanced mid-water turbulent dissipation rates, based on data from the Laptev Sea continental slope in summer 2018. Prior to the INL observation, co-located long-term current velocity data show a period of intensified down-slope flow and isopycnal depression, which might have caused the enhanced mid-water turbulence via the generation of an unsteady lee wave. Similar periods of intensified down-slope flow were observed mostly in the ice-free season, suggesting an intensification of cross-slope particle transport in the future. The presented evidence for the existence of turbid INLs above28 the Laptev Sea slope and their generation mechanism provide new insights into the im29portant particle transport dynamics in this rapidly changing environment.

AB - Intermediate nepheloid layers (INLs) form important pathways for the cross-slope transport and subsequent vertical export of particulate matter, including carbon. While intermediate maxima in particle settling fluxes have been reported in the Eurasian Basin of the Arctic Ocean, direct observations of turbid INLs above the surrounding continental slope are still lacking. In this study, we provide the first direct evidence of a turbid INL, coinciding with enhanced mid-water turbulent dissipation rates, based on data from the Laptev Sea continental slope in summer 2018. Prior to the INL observation, co-located long-term current velocity data show a period of intensified down-slope flow and isopycnal depression, which might have caused the enhanced mid-water turbulence via the generation of an unsteady lee wave. Similar periods of intensified down-slope flow were observed mostly in the ice-free season, suggesting an intensification of cross-slope particle transport in the future. The presented evidence for the existence of turbid INLs above28 the Laptev Sea slope and their generation mechanism provide new insights into the im29portant particle transport dynamics in this rapidly changing environment.

M3 - Article

JO - Geophysical Research Letters

JF - Geophysical Research Letters

SN - 0094-8276

M1 - e2021GL092988

ER -