Biogeochemical modelling of dissolved oxygen in a changing ocean

TY - JOUR

T1 - Biogeochemical modelling of dissolved oxygen in a changing ocean

AU - Andrews, Oliver

AU - Buitenhuis, Erik

AU - Le Quéré, Corinne

AU - Suntharalingam, Parvadha

N1 - Publisher Copyright: © 2017 The Author(s) Published by the Royal Society. All rights reserved.

PY - 2017/9/13

Y1 - 2017/9/13

N2 - Secular decreases in dissolved oxygen concentration have been observed within the tropical oxygen minimum zones (OMZs) and at mid- to high latitudes over the last approximately 50 years. Earth system model projections indicate that a reduction in the oxygen inventory of the global ocean, termed ocean deoxygenation, is a likely consequence of on-going anthropogenic warming. Current models are, however, unable to consistently reproduce the observed trends and variability of recent decades, particularly within the established tropical OMZs. Here, we conduct a series of targeted hindcast model simulations using a state-of-the-art global ocean biogeochemistry model in order to explore and review biases in model distributions of oceanic oxygen. We show that the largest magnitude of uncertainty is entrained into ocean oxygen response patterns due to model parametrization of pCO2-sensitive C:N ratios in carbon fixation and imposed atmospheric forcing data. Inclusion of a pCO2-sensitive C:N ratio drives historical oxygen depletion within the ocean interior due to increased organic carbon export and subsequent remineralization. Atmospheric forcing is shown to influence simulated interannual variability in ocean oxygen, particularly due to differences in imposed variability of wind stress and heat fluxes. This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'.

AB - Secular decreases in dissolved oxygen concentration have been observed within the tropical oxygen minimum zones (OMZs) and at mid- to high latitudes over the last approximately 50 years. Earth system model projections indicate that a reduction in the oxygen inventory of the global ocean, termed ocean deoxygenation, is a likely consequence of on-going anthropogenic warming. Current models are, however, unable to consistently reproduce the observed trends and variability of recent decades, particularly within the established tropical OMZs. Here, we conduct a series of targeted hindcast model simulations using a state-of-the-art global ocean biogeochemistry model in order to explore and review biases in model distributions of oceanic oxygen. We show that the largest magnitude of uncertainty is entrained into ocean oxygen response patterns due to model parametrization of pCO2-sensitive C:N ratios in carbon fixation and imposed atmospheric forcing data. Inclusion of a pCO2-sensitive C:N ratio drives historical oxygen depletion within the ocean interior due to increased organic carbon export and subsequent remineralization. Atmospheric forcing is shown to influence simulated interannual variability in ocean oxygen, particularly due to differences in imposed variability of wind stress and heat fluxes. This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'.

KW - Biogeochemical modelling

KW - Climate change

KW - Ocean deoxygenation

UR - http://www.scopus.com/inward/record.url?scp=85026862970&partnerID=8YFLogxK

U2 - 10.1098/rsta.2016.0328

DO - 10.1098/rsta.2016.0328

M3 - Article

C2 - 28784705

AN - SCOPUS:85026862970

SN - 1364-503X

VL - 375

JO - Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences

JF - Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences

IS - 2102

M1 - 20160328

ER -