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One possible uncertainty in CMIP5 projections of low‐oxygen water volume in the Eastern Tropical Pacific
Author(s) -
Shigemitsu M.,
Yamamoto A.,
Oka A.,
Yamanaka Y.
Publication year - 2017
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/2016gb005447
Subject(s) - coupled model intercomparison project , biogeochemical cycle , environmental science , oxygen , volume (thermodynamics) , climatology , flux (metallurgy) , climate model , atmospheric sciences , oceanography , climate change , chemistry , geology , environmental chemistry , physics , organic chemistry , quantum mechanics
Using the results from nine Earth system models submitted to the Coupled Model Intercomparison Project Phase 5 (CMIP5), we identify the Eastern Tropical Pacific (ETP) as the region with the greatest uncertainty of future changes in oxygen‐deficient (<30 μ M ) water volumes since different models variously project both positive and negative changes in the oxygen‐deficient volume and export flux there. We investigate the factors controlling future changes in oxygen‐deficient volume in the ETP with global warming using a single off‐line biogeochemical model. Oxygen budget analysis clarifies that the Equatorial Undercurrent (EUC) is the key mechanism controlling future variations in the oxygen‐deficient volume in the ETP in our model. From the outputs of all of the CMIP5 models and our model, we identify a significant negative relationship between changes in the EUC volume transport and the oxygen‐deficient water volume from the present to the end of the 21st century, which indicates that the response of the EUC to global warming leads to one possible uncertainty in future projections of oxygen‐deficient volume in the ETP.