Elucidation of the mechanism for the phase change in the tropical Pacific decadal variability during the mid 1990s

2016 Fiscal Year Final Research Report

• Project/Area Number: 26400471
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Meteorology/Physical oceanography/Hydrology
• Research Institution: Japan, Meteorological Research Institute
• Principal Investigator: Yamanaka Goro 気象庁気象研究所, 海洋・地球化学研究部, 室長 (60442745)
• Co-Investigator(Renkei-kenkyūsha): NAKANO Hideyuki 気象庁・気象研究所, 海洋地球化学研究部, 主任研究官 (60370334)
• Research Collaborator: ISHIZAKI Hiroshi 気象庁・気象研究所, 海洋地球化学研究部, 客員研究員
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 大気海洋相互作用 / 十年規模変動 / 海面水位 / 太平洋亜熱帯セル / 熱帯太平洋 / 地球温暖化の停滞 / 海洋大循環モデル / 海洋物質循環

Outline of Final Research Achievements

The processes of the phase change in the tropical Pacific decadal variability are examined using numerical models and atmospheric reanalysis data. The tropical Pacific decadal variability, which is associated with the shallow overturning circulation of the Pacific, is found not only in the physical fields, such as sea surface temperatures and sea surface height, but also in the bio-geochemical fields like anthropogenic carbon dioxide. It is found that heat exchange between the tropical and subtropical regions plays an important role in the weakening of the positive phase around 1985. It is also suggested that the increase in the poleward heat transport associated with the enhanced equatorial trade winds, which originate from the atmospheric variability in the mid-latitude North Pacific, mainly contributes to the enhancement of the negative phase after the mid-1990s.

Free Research Field

海洋物理学