論文

査読有り
2014年8月

Long-term variation in sea ice production and its relation to the intermediate water in the Sea of Okhotsk

PROGRESS IN OCEANOGRAPHY
  • Haruhiko Kashiwase
  • ,
  • Kay I. Ohshima
  • ,
  • Sohey Nihashi

126
開始ページ
21
終了ページ
32
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.pocean.2014.05.004
出版者・発行元
PERGAMON-ELSEVIER SCIENCE LTD

Overturning in the North Pacific extending to the intermediate layer (about 200-800 m depth) originates from the sinking of dense shelf water (DSW) formed by sea ice production in the Okhotsk coastal polynyas. It has been suggested that this overturning has weakened during the past 50 years. The purpose of this study is to clarify the long-term variability of sea ice production in the polynyas and to discuss its linkage with DSW formation and the overturning. First, we have developed a thin ice thickness retrieval algorithm using Special Sensor Microwave/Imager (SSM/I) data for the Sea of Okhotsk, and have estimated the ice production for 21 years (1988-2008) by calculating heat flux from SSM/I-derived ice thickness. From a comparison with atmospheric variables, it is suggested that interannual variability of sea ice production in the polynyas can be explained mainly by three atmospheric parameters: autumn air temperature northwest of the sea, winter air temperature north of the sea, and late winter offshoreward wind speed north of the sea. By using these parameters from atmospheric reanalysis data, the annual ice production for the 34 years period from 1974 to 2008 is reconstructed from a multiple regression coefficient analysis. The reconstructed ice production shows a significant decreasing trend of similar to 11.4% over 34 years, which is mainly explained by the warming of autumn air temperature. It is also found that the variation in the annual total ice production corresponds well with the potential temperature variation in Okhotsk Sea Intermediate Water (OSIW). This first observational evidence of a linkage between the annual total ice production and OSIW supports a hypothesis that decreasing ice production in the Okhotsk coastal polynyas, at least in part, has led to weakening of the overturning in the North Pacific. (C) 2014 Elsevier Ltd. All rights reserved.

リンク情報
DOI
https://doi.org/10.1016/j.pocean.2014.05.004
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000340851400003&DestApp=WOS_CPL
ID情報
  • DOI : 10.1016/j.pocean.2014.05.004
  • ISSN : 0079-6611
  • Web of Science ID : WOS:000340851400003

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