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Interannual Variation of Modified Circumpolar Deep Water in the Dotson‐Getz Trough, West Antarctica
Author(s) -
Kim TaeWan,
Yang Hee Won,
Dutrieux Pierre,
Wåhlin Anna K.,
Jenkins Adrian,
Kim Yeong Gi,
Ha Ho Kyung,
Kim ChangSin,
Cho KyoungHo,
Park Taewook,
Park Jisoo,
Lee SangHoon,
Cho YangKi
Publication year - 2021
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2021jc017491
Subject(s) - oceanography , upwelling , ice shelf , geology , hydrography , trough (economics) , ekman transport , continental shelf , sea ice , circumpolar deep water , climatology , circumpolar star , cryosphere , deep water , north atlantic deep water , economics , macroeconomics
Widespread ice shelf thinning has been recorded in the Amundsen Sea in recent decades, driven by basal melting and intrusions of relatively warm Circumpolar Deep Water (CDW) onto the continental shelf. The Dotson Ice Shelf (DIS) is located to the south of the Amundsen Sea polynya, and has a high basal melting rate because modified CDW (mCDW) fills the Dotson‐Getz Trough (DGT) and reaches the base of the ice shelf. Here, hydrographic data in the DGT obtained during seven oceanographic surveys from 2007 to 2018 were used to study the interannual variation in mCDW volume and properties and their causes. Although mCDW volume showed relatively weak interannual variations at the continental shelf break, these variations intensified southward and reached a maximum in front of the DIS. There, the mCDW volume was ∼8,000 km 3 in 2007, rapidly decreased to 4,700 km 3 in 2014 before rebounding to 7,300 km 3 in 2018. We find that such interannual variability is coherent with local Ekman pumping integrated along the DGT modulated by the presence of sea ice, and complementing earlier theories involving shelf break winds only. The interannual variability in strength of the dominant south‐southeast coastal wind modulates the amplitude of Ekman upwelling along the eastern boundary of the Amundsen Sea polynya during the austral summers of the surveyed years, apparently leading to change in the volume of mCDW along the DGT. We note a strong correlation between the wind variability and the longitudinal location of the Amundsen Sea Low.