Freshwater and brine behaviours in the Arctic Ocean deduced from historical data of ð18O and alkalinity (1929-2002 AD)

The long-term data sets of total alkalinity (TA) (1929–2002 A.D.) and δ18O (1966–2002 A.D.) are used to investigate freshwater and brine distributions in the Arctic Ocean. Fractions of sea ice meltwater and other freshwaters (OF) (precipitation, river runoff, and freshwater carried by Pacific water...

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Bibliographic Details
Published in:Journal of Geophysical Research
Main Authors: Yamamoto-Kawai, Michiyo, Tanaka, Noriyuki, Pivovarov, Sergey
Format: Article in Journal/Newspaper
Language:English
Published: AGU 2005
Subjects:
Arctic
Arctic Ocean
East Siberian Sea
Mackenzie River
Mendeleyev
Mendeleyev Ridge
Pacific
Chukchi
Fram Strait
Mackenzie river
Sea ice
Online Access:https://oceanrep.geomar.de/id/eprint/31674/
https://oceanrep.geomar.de/id/eprint/31674/1/Yamamoto-Kawai_et_al-2005-Journal_of_Geophysical_Research__Solid_Earth_%281978-2012%29.pdf
https://doi.org/10.1029/2004JC002793
Description
Summary:The long-term data sets of total alkalinity (TA) (1929–2002 A.D.) and δ18O (1966–2002 A.D.) are used to investigate freshwater and brine distributions in the Arctic Ocean. Fractions of sea ice meltwater and other freshwaters (OF) (precipitation, river runoff, and freshwater carried by Pacific water implied as salinity deficit) are calculated on the basis of salinity-TA and salinity-δ18O relationships. Rejected brine during sea ice growth resides in surface water in the central Arctic Ocean, while net melting is found along the surface flow of water from the Pacific and Atlantic oceans. Distribution of OF at 10 m water depth suggests that Russian runoff leaves the shelf mainly west of the Mendeleyev Ridge, enters into the deep basin, and exits from the ocean through the western part of Fram Strait. The influence of Mackenzie River water is limited in the region and in depth. Accumulation of freshwater in the Canadian Basin is caused by deep penetration of OF with brine, indicating the transport of freshwater by shelf-derived water. The major origin of shelf-derived water entering into the upper halocline layer in the Canadian Basin should be the Chukchi and East Siberian Sea shelves, and the main freshwater sources are the salinity deficit of Pacific water and/or Russian runoff. An increase in OF inventory accompanied by an increase in brine content may suggest an increase of the shelf-derived water supply into the western Canadian Basin in anticyclonic years.

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