TY - JOUR
T1 - Meltwater layer dynamics in a central Arctic lead
T2 - Effects of lead width, re-freezing, and mixing during late summer
AU - Nomura, Daiki
AU - Kawaguchi, Yusuke
AU - Webb, Alison L.
AU - Li, Yuhong
AU - Dall'osto, Manuel
AU - Schmidt, Katrin
AU - Droste, Elise S.
AU - Chamberlain, Emelia J.
AU - Kolabutin, Nikolai
AU - Shimanchuk, Egor
AU - Hoppmann, Mario
AU - Gallagher, Michael R.
AU - Meyer, Hanno
AU - Mellat, Moein
AU - Bauch, Dorothea
AU - Gabarró, Carolina
AU - Smith, Madison M.
AU - Inoue, Jun
AU - Damm, Ellen
AU - Delille, Bruno
N1 - Publisher Copyright:
Copyright: © 2023 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See http://creativecommons.org/licenses/by/4.0/.
PY - 2023/5/15
Y1 - 2023/5/15
N2 - Leads play an important role in the exchange of heat, gases, vapour, and particles between seawater and the atmosphere in ice-covered polar oceans. In summer, these processes can be modified significantly by the formation of a meltwater layer at the surface, yet we know little about the dynamics of meltwater layer formation and persistence. During the drift campaign of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC), we examined how variation in lead width, re-freezing, and mixing events affected the vertical structure of lead waters during late summer in the central Arctic. At the beginning of the 4-week survey period, a meltwater layer occupied the surface 0.8 m of the lead, and temperature and salinity showed strong vertical gradients. Stable oxygen isotopes indicate that the meltwater consisted mainly of sea ice meltwater rather than snow meltwater. During the first half of the survey period (before freezing), the meltwater layer thickness decreased rapidly as lead width increased and stretched the layer horizontally. During the latter half of the survey period (after freezing of the lead surface), stratification weakened and the meltwater layer became thinner before disappearing completely due to surface ice formation and mixing processes. Removal of meltwater during surface ice formation explained about 43% of the reduction in thickness of the meltwater layer. The remaining approximate 57% could be explained by mixing within the water column initiated by disturbance of the lower boundary of the meltwater layer through wind-induced ice floe drift. These results indicate that rapid, dynamic changes to lead water structure can have potentially significant effects on the exchange of physical and biogeochemical components throughout the atmosphere-lead-underlying seawater system.
AB - Leads play an important role in the exchange of heat, gases, vapour, and particles between seawater and the atmosphere in ice-covered polar oceans. In summer, these processes can be modified significantly by the formation of a meltwater layer at the surface, yet we know little about the dynamics of meltwater layer formation and persistence. During the drift campaign of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC), we examined how variation in lead width, re-freezing, and mixing events affected the vertical structure of lead waters during late summer in the central Arctic. At the beginning of the 4-week survey period, a meltwater layer occupied the surface 0.8 m of the lead, and temperature and salinity showed strong vertical gradients. Stable oxygen isotopes indicate that the meltwater consisted mainly of sea ice meltwater rather than snow meltwater. During the first half of the survey period (before freezing), the meltwater layer thickness decreased rapidly as lead width increased and stretched the layer horizontally. During the latter half of the survey period (after freezing of the lead surface), stratification weakened and the meltwater layer became thinner before disappearing completely due to surface ice formation and mixing processes. Removal of meltwater during surface ice formation explained about 43% of the reduction in thickness of the meltwater layer. The remaining approximate 57% could be explained by mixing within the water column initiated by disturbance of the lower boundary of the meltwater layer through wind-induced ice floe drift. These results indicate that rapid, dynamic changes to lead water structure can have potentially significant effects on the exchange of physical and biogeochemical components throughout the atmosphere-lead-underlying seawater system.
KW - Arctic Ocean
KW - Lead
KW - Meltwater
KW - Mixing
KW - Re-freezing
KW - Sea ice
UR - http://www.scopus.com/inward/record.url?scp=85168997135&partnerID=8YFLogxK
UR - https://pearl.plymouth.ac.uk/context/gees-research/article/2417/viewcontent/elementa.2022.00102.pdf
U2 - 10.1525/elementa.2022.00102
DO - 10.1525/elementa.2022.00102
M3 - Article
AN - SCOPUS:85168997135
SN - 2325-1026
VL - 11
JO - Elementa
JF - Elementa
IS - 1
M1 - 00102
ER -