Articles | Volume 17, issue 5
https://doi.org/10.5194/os-17-1303-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-17-1303-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
28 Sep 2021
Research article |
| 28 Sep 2021
| 28 Sep 2021
Causes of uncertainties in the representation of the Arabian Sea oxygen minimum zone in CMIP5 models
Henrike Schmidt
CORRESPONDING AUTHOR
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
Kiel University, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
Julia Getzlaff
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
Ulrike Löptien
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
Kiel University, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
Andreas Oschlies
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
Kiel University, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
Related authors
Tim Rixen, Greg Cowie, Birgit Gaye, Joaquim Goes, Helga do Rosário Gomes, Raleigh R. Hood, Zouhair Lachkar, Henrike Schmidt, Joachim Segschneider, and Arvind Singh
Biogeosciences, 17, 6051–6080, https://doi.org/10.5194/bg-17-6051-2020, https://doi.org/10.5194/bg-17-6051-2020, 2020
Short summary
Short summary
The northern Indian Ocean hosts an extensive oxygen minimum zone (OMZ), which intensified due to human-induced global changes. This includes the occurrence of anoxic events on the Indian shelf and affects benthic ecosystems and the pelagic ecosystem structure in the Arabian Sea. Consequences for biogeochemical cycles are unknown, which, in addition to the poor representation of mesoscale features, reduces the reliability of predictions of the future OMZ development in the northern Indian Ocean.
Henrike Schmidt, Rena Czeschel, and Martin Visbeck
Ocean Sci., 16, 1459–1474, https://doi.org/10.5194/os-16-1459-2020, https://doi.org/10.5194/os-16-1459-2020, 2020
Short summary
Short summary
Our investigations give detailed insight on the seasonally changing current system at intermediate depth in the Arabian Sea that is influenced by the monsoon. The changing currents influence the oxygen transport in the interior ocean and thus allow us to draw conclusions on the maintenance and seasonal variability of the upper part of the oxygen minimum zone in the Arabian Sea.
Henrike Schmidt, Rena Czeschel, and Martin Visbeck
Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-168, https://doi.org/10.5194/bg-2019-168, 2019
Manuscript not accepted for further review
Short summary
Short summary
Our investigations give a detailed insight on the changing current system at intermediate depth in the Arabian Sea and allow to draw conclusions on ventilation pathways of the oxygen minimum zone and its seasonal variability. In response to the monsoon system the boundary currents change direction and feature a regionally varying ventilation pattern.
Miriam Tivig, David P. Keller, and Andreas Oschlies
Biogeosciences, 21, 4469–4493, https://doi.org/10.5194/bg-21-4469-2024, https://doi.org/10.5194/bg-21-4469-2024, 2024
Short summary
Short summary
Marine biological production is highly dependent on the availability of nitrogen and phosphorus. Rivers are the main source of phosphorus to the oceans but poorly represented in global model oceans. We include dissolved nitrogen and phosphorus from river export in a global model ocean and find that the addition of riverine phosphorus affects marine biology on millennial timescales more than riverine nitrogen alone. Globally, riverine phosphorus input increases primary production rates.
Na Li, Christopher J. Somes, Angela Landolfi, Chia-Te Chien, Markus Pahlow, and Andreas Oschlies
Biogeosciences, 21, 4361–4380, https://doi.org/10.5194/bg-21-4361-2024, https://doi.org/10.5194/bg-21-4361-2024, 2024
Short summary
Short summary
N is a crucial nutrient that limits phytoplankton growth in large ocean areas. The amount of oceanic N is governed by the balance of N2 fixation and denitrification. Here we incorporate benthic denitrification into an Earth system model with variable particulate stoichiometry. Our model compares better to the observed surface nutrient distributions, marine N2 fixation, and primary production. Benthic denitrification plays an important role in marine N and C cycling and hence the global climate.
Timothée Bourgeois, Olivier Torres, Friederike Fröb, Aurich Jeltsch-Thömmes, Giang G. Tran, Jörg Schwinger, Thomas L. Frölicher, Jean Negrel, David Keller, Andreas Oschlies, Laurent Bopp, and Fortunat Joos
EGUsphere, https://doi.org/10.5194/egusphere-2024-2768, https://doi.org/10.5194/egusphere-2024-2768, 2024
Short summary
Short summary
Anthropogenic greenhouse gas emissions significantly impact ocean ecosystems through climate change and acidification, leading to either progressive or abrupt changes. This study maps the crossing of physical and ecological limits for various ocean impact metrics under three emission scenarios. Using Earth system models, we identify when these limits are exceeded, highlighting the urgent need for ambitious climate action to safeguard the world's oceans and ecosystems.
Haichao Guo, Wolfgang Koeve, Andreas Oschlies, Yan-Chun He, Tronje Peer Kemena, Lennart Gerke, and Iris Kriest
EGUsphere, https://doi.org/10.5194/egusphere-2024-2552, https://doi.org/10.5194/egusphere-2024-2552, 2024
Short summary
Short summary
We evaluated the effectiveness of the Inverse Gaussian Transit Time Distribution (IG-TTD) in estimating the mean state and temporal changes of seawater age, defined as the duration since water last contact with atmosphere, within the tropical thermocline. Results suggest IG-TTD underestimates seawater age. Besides, IG-TTD constrained by a single tracer gives spurious trends of water age. Incorporating an additional tracer improves IG-TTD's accuracy in estimating temporal change of seawater age.
Tianfei Xue, Jens Terhaar, A. E. Friederike Prowe, Thomas L. Frölicher, Andreas Oschlies, and Ivy Frenger
Biogeosciences, 21, 2473–2491, https://doi.org/10.5194/bg-21-2473-2024, https://doi.org/10.5194/bg-21-2473-2024, 2024
Short summary
Short summary
Phytoplankton play a crucial role in marine ecosystems. However, climate change's impact on phytoplankton biomass remains uncertain, particularly in the Southern Ocean. In this region, phytoplankton biomass within the water column is likely to remain stable in response to climate change, as supported by models. This stability arises from a shallower mixed layer, favoring phytoplankton growth but also increasing zooplankton grazing due to phytoplankton concentration near the surface.
Katja Fennel, Matthew C. Long, Christopher Algar, Brendan Carter, David Keller, Arnaud Laurent, Jann Paul Mattern, Ruth Musgrave, Andreas Oschlies, Josiane Ostiguy, Jaime B. Palter, and Daniel B. Whitt
State Planet, 2-oae2023, 9, https://doi.org/10.5194/sp-2-oae2023-9-2023, https://doi.org/10.5194/sp-2-oae2023-9-2023, 2023
Short summary
Short summary
This paper describes biogeochemical models and modelling techniques for applications related to ocean alkalinity enhancement (OAE) research. Many of the most pressing OAE-related research questions cannot be addressed by observation alone but will require a combination of skilful models and observations. We present illustrative examples with references to further information; describe limitations, caveats, and future research needs; and provide practical recommendations.
Andreas Oschlies, Lennart T. Bach, Rosalind E. M. Rickaby, Terre Satterfield, Romany Webb, and Jean-Pierre Gattuso
State Planet, 2-oae2023, 1, https://doi.org/10.5194/sp-2-oae2023-1-2023, https://doi.org/10.5194/sp-2-oae2023-1-2023, 2023
Short summary
Short summary
Reaching promised climate targets will require the deployment of carbon dioxide removal (CDR). Marine CDR options receive more and more interest. Based on idealized theoretical studies, ocean alkalinity enhancement (OAE) appears as a promising marine CDR method. We provide an overview on the current situation of developing OAE as a marine CDR method and describe the history that has led to the creation of the OAE research best practice guide.
Iris Kriest, Julia Getzlaff, Angela Landolfi, Volkmar Sauerland, Markus Schartau, and Andreas Oschlies
Biogeosciences, 20, 2645–2669, https://doi.org/10.5194/bg-20-2645-2023, https://doi.org/10.5194/bg-20-2645-2023, 2023
Short summary
Short summary
Global biogeochemical ocean models are often subjectively assessed and tuned against observations. We applied different strategies to calibrate a global model against observations. Although the calibrated models show similar tracer distributions at the surface, they differ in global biogeochemical fluxes, especially in global particle flux. Simulated global volume of oxygen minimum zones varies strongly with calibration strategy and over time, rendering its temporal extrapolation difficult.
Jiajun Wu, David P. Keller, and Andreas Oschlies
Earth Syst. Dynam., 14, 185–221, https://doi.org/10.5194/esd-14-185-2023, https://doi.org/10.5194/esd-14-185-2023, 2023
Short summary
Short summary
In this study we investigate an ocean-based carbon dioxide removal method: macroalgae open-ocean mariculture and sinking (MOS), which aims to cultivate seaweed in the open-ocean surface and to sink matured biomass quickly to the deep seafloor. Our results suggest that MOS has considerable potential as an ocean-based CDR method. However, MOS has inherent side effects on marine ecosystems and biogeochemistry, which will require careful evaluation beyond this first idealized modeling study.
Chia-Te Chien, Jonathan V. Durgadoo, Dana Ehlert, Ivy Frenger, David P. Keller, Wolfgang Koeve, Iris Kriest, Angela Landolfi, Lavinia Patara, Sebastian Wahl, and Andreas Oschlies
Geosci. Model Dev., 15, 5987–6024, https://doi.org/10.5194/gmd-15-5987-2022, https://doi.org/10.5194/gmd-15-5987-2022, 2022
Short summary
Short summary
We present the implementation and evaluation of a marine biogeochemical model, Model of Oceanic Pelagic Stoichiometry (MOPS) in the Flexible Ocean and Climate Infrastructure (FOCI) climate model. FOCI-MOPS enables the simulation of marine biological processes, the marine carbon, nitrogen and oxygen cycles, and air–sea gas exchange of CO2 and O2. As shown by our evaluation, FOCI-MOPS shows an overall adequate performance that makes it an appropriate tool for Earth climate system simulations.
Tianfei Xue, Ivy Frenger, A. E. Friederike Prowe, Yonss Saranga José, and Andreas Oschlies
Biogeosciences, 19, 455–475, https://doi.org/10.5194/bg-19-455-2022, https://doi.org/10.5194/bg-19-455-2022, 2022
Short summary
Short summary
The Peruvian system supports 10 % of the world's fishing yield. In the Peruvian system, wind and earth’s rotation bring cold, nutrient-rich water to the surface and allow phytoplankton to grow. But observations show that it grows worse at high upwelling. Using a model, we find that high upwelling happens when air mixes the water the most. Then phytoplankton is diluted and grows slowly due to low light and cool upwelled water. This study helps to estimate how it might change in a warming climate.
Karin Kvale, David P. Keller, Wolfgang Koeve, Katrin J. Meissner, Christopher J. Somes, Wanxuan Yao, and Andreas Oschlies
Geosci. Model Dev., 14, 7255–7285, https://doi.org/10.5194/gmd-14-7255-2021, https://doi.org/10.5194/gmd-14-7255-2021, 2021
Short summary
Short summary
We present a new model of biological marine silicate cycling for the University of Victoria Earth System Climate Model (UVic ESCM). This new model adds diatoms, which are a key aspect of the biological carbon pump, to an existing ecosystem model. Our modifications change how the model responds to warming, with net primary production declining more strongly than in previous versions. Diatoms in particular are simulated to decline with climate warming due to their high nutrient requirements.
Olaf Duteil, Ivy Frenger, and Julia Getzlaff
Ocean Sci., 17, 1489–1507, https://doi.org/10.5194/os-17-1489-2021, https://doi.org/10.5194/os-17-1489-2021, 2021
Short summary
Short summary
The large oxygen minimum zones in the tropical Pacific Ocean are still not well represented by typical climate models. We analyze a set of ocean models and highlight the fact that an oxygen concentration that is too low at intermediate depth in the subtropical regions associated with a sluggish representation of the intermediate equatorial current system may be responsible for the overly large extension of the modeled oxygen minimum zones, potentially hampering future projections.
Maria-Theresia Verwega, Christopher J. Somes, Markus Schartau, Robyn Elizabeth Tuerena, Anne Lorrain, Andreas Oschlies, and Thomas Slawig
Earth Syst. Sci. Data, 13, 4861–4880, https://doi.org/10.5194/essd-13-4861-2021, https://doi.org/10.5194/essd-13-4861-2021, 2021
Short summary
Short summary
This work describes a ready-to-use collection of particulate organic carbon stable isotope ratio data sets. It covers the 1960s–2010s and all main oceans, providing meta-information and gridded data. The best coverage exists in Atlantic, Indian and Southern Ocean surface waters during the 1990s. It indicates no major difference between methods and shows decreasing values towards high latitudes, with the lowest in the Southern Ocean, and a long-term decline in all regions but the Southern Ocean.
Miriam Tivig, David P. Keller, and Andreas Oschlies
Biogeosciences, 18, 5327–5350, https://doi.org/10.5194/bg-18-5327-2021, https://doi.org/10.5194/bg-18-5327-2021, 2021
Short summary
Short summary
Nitrogen is one of the most important elements for life in the ocean. A major source is the riverine discharge of dissolved nitrogen. While global models often omit rivers as a nutrient source, we included nitrogen from rivers in our Earth system model and found that additional nitrogen affected marine biology not only locally but also in regions far off the coast. Depending on regional conditions, primary production was enhanced or even decreased due to internal feedbacks in the nitrogen cycle.
Jaard Hauschildt, Soeren Thomsen, Vincent Echevin, Andreas Oschlies, Yonss Saranga José, Gerd Krahmann, Laura A. Bristow, and Gaute Lavik
Biogeosciences, 18, 3605–3629, https://doi.org/10.5194/bg-18-3605-2021, https://doi.org/10.5194/bg-18-3605-2021, 2021
Short summary
Short summary
In this paper we quantify the subduction of upwelled nitrate due to physical processes on the order of several kilometers in the coastal upwelling off Peru and its effect on primary production. We also compare the prepresentation of these processes in a high-resolution simulation (~2.5 km) with a more coarsely resolved simulation (~12 km). To do this, we combine high-resolution shipboard observations of physical and biogeochemical parameters with a complex biogeochemical model configuration.
Mariana Hill Cruz, Iris Kriest, Yonss Saranga José, Rainer Kiko, Helena Hauss, and Andreas Oschlies
Biogeosciences, 18, 2891–2916, https://doi.org/10.5194/bg-18-2891-2021, https://doi.org/10.5194/bg-18-2891-2021, 2021
Short summary
Short summary
In this study we use a regional biogeochemical model of the eastern tropical South Pacific Ocean to implicitly simulate the effect that fluctuations in populations of small pelagic fish, such as anchovy and sardine, may have on the biogeochemistry of the northern Humboldt Current System. To do so, we vary the zooplankton mortality in the model, under the assumption that these fishes eat zooplankton. We also evaluate the model for the first time against mesozooplankton observations.
Britta Munkes, Ulrike Löptien, and Heiner Dietze
Biogeosciences, 18, 2347–2378, https://doi.org/10.5194/bg-18-2347-2021, https://doi.org/10.5194/bg-18-2347-2021, 2021
Short summary
Short summary
Cyanobacteria blooms can strongly aggravate eutrophication problems of water bodies. Their controls are, however, not comprehensively understood, which impedes effective management and protection plans. Here we review the current understanding of cyanobacteria blooms. Juxtaposition of respective field and laboratory studies with state-of-the-art mathematical models reveals substantial uncertainty associated with nutrient demands, grazing, and death of cyanobacteria.
Tim Rixen, Greg Cowie, Birgit Gaye, Joaquim Goes, Helga do Rosário Gomes, Raleigh R. Hood, Zouhair Lachkar, Henrike Schmidt, Joachim Segschneider, and Arvind Singh
Biogeosciences, 17, 6051–6080, https://doi.org/10.5194/bg-17-6051-2020, https://doi.org/10.5194/bg-17-6051-2020, 2020
Short summary
Short summary
The northern Indian Ocean hosts an extensive oxygen minimum zone (OMZ), which intensified due to human-induced global changes. This includes the occurrence of anoxic events on the Indian shelf and affects benthic ecosystems and the pelagic ecosystem structure in the Arabian Sea. Consequences for biogeochemical cycles are unknown, which, in addition to the poor representation of mesoscale features, reduces the reliability of predictions of the future OMZ development in the northern Indian Ocean.
Henrike Schmidt, Rena Czeschel, and Martin Visbeck
Ocean Sci., 16, 1459–1474, https://doi.org/10.5194/os-16-1459-2020, https://doi.org/10.5194/os-16-1459-2020, 2020
Short summary
Short summary
Our investigations give detailed insight on the seasonally changing current system at intermediate depth in the Arabian Sea that is influenced by the monsoon. The changing currents influence the oxygen transport in the interior ocean and thus allow us to draw conclusions on the maintenance and seasonal variability of the upper part of the oxygen minimum zone in the Arabian Sea.
Markus Pahlow, Chia-Te Chien, Lionel A. Arteaga, and Andreas Oschlies
Geosci. Model Dev., 13, 4663–4690, https://doi.org/10.5194/gmd-13-4663-2020, https://doi.org/10.5194/gmd-13-4663-2020, 2020
Short summary
Short summary
The stoichiometry of marine biotic processes is important for the regulation of atmospheric CO2 and hence the global climate. We replace a simplistic, fixed-stoichiometry plankton module in an Earth system model with an optimal-regulation model with variable stoichiometry. Our model compares better to the observed carbon transfer from the surface to depth and surface nutrient distributions. This work could aid our ability to describe and project the role of marine ecosystems in the Earth system.
Chia-Te Chien, Markus Pahlow, Markus Schartau, and Andreas Oschlies
Geosci. Model Dev., 13, 4691–4712, https://doi.org/10.5194/gmd-13-4691-2020, https://doi.org/10.5194/gmd-13-4691-2020, 2020
Short summary
Short summary
We demonstrate sensitivities of tracers to parameters of a new optimality-based plankton–ecosystem model (OPEM) in the UVic-ESCM. We find that changes in phytoplankton subsistence nitrogen quota strongly impact the nitrogen inventory, nitrogen fixation, and elemental stoichiometry of ordinary phytoplankton and diazotrophs. We introduce a new likelihood-based metric for model calibration, and it shows the capability of constraining globally averaged oxygen, nitrate, and DIC concentrations.
Nadine Mengis, David P. Keller, Andrew H. MacDougall, Michael Eby, Nesha Wright, Katrin J. Meissner, Andreas Oschlies, Andreas Schmittner, Alexander J. MacIsaac, H. Damon Matthews, and Kirsten Zickfeld
Geosci. Model Dev., 13, 4183–4204, https://doi.org/10.5194/gmd-13-4183-2020, https://doi.org/10.5194/gmd-13-4183-2020, 2020
Short summary
Short summary
In this paper, we evaluate the newest version of the University of Victoria Earth System Climate Model (UVic ESCM 2.10). Combining recent model developments as a joint effort, this version is to be used in the next phase of model intercomparison and climate change studies. The UVic ESCM 2.10 is capable of reproducing changes in historical temperature and carbon fluxes well. Additionally, the model is able to reproduce the three-dimensional distribution of many ocean tracers.
Sabine Mathesius, Julia Getzlaff, Heiner Dietze, Andreas Oschlies, and Markus Schartau
Earth Syst. Sci. Data, 12, 1775–1787, https://doi.org/10.5194/essd-12-1775-2020, https://doi.org/10.5194/essd-12-1775-2020, 2020
Short summary
Short summary
Controlled manipulation of environmental conditions within large enclosures in the ocean, pelagic mesocosms, has become a standard method to explore responses of marine plankton communities to anthropogenic change. Among the challenges of interpreting mesocosm data is the often uncertain role of vertical mixing. This study introduces a mesocosm mixing model that is able to estimate vertical diffusivities and thus provides a tool for future mesocosm data analyses that account for mixing.
Iris Kriest, Paul Kähler, Wolfgang Koeve, Karin Kvale, Volkmar Sauerland, and Andreas Oschlies
Biogeosciences, 17, 3057–3082, https://doi.org/10.5194/bg-17-3057-2020, https://doi.org/10.5194/bg-17-3057-2020, 2020
Short summary
Short summary
Constants of global biogeochemical ocean models are often tuned
by handto match observations of nutrients or oxygen. We investigate the effect of this tuning by optimising six constants of a global biogeochemical model, simulated in five different offline circulations. Optimal values for three constants adjust to distinct features of the circulation applied and can afterwards be swapped among the circulations, without losing too much of the model's fit to observed quantities.
Ulrike Löptien and Heiner Dietze
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-96, https://doi.org/10.5194/bg-2020-96, 2020
Manuscript not accepted for further review
Short summary
Short summary
Nitrogen fixation, conducted by specific microorganisms, makes molecular nitrogen available for marine biota. By this means this process exerts major control on the growth of algae in the ocean. This study compares two contemporary paradigms, anticipating the ecological niche of N-fixing organisms in an Earth System Model. We illustrate respective uncertainties in climate projections and suggest specific observations to advance the reliable representation of nitrogen fixation in numerical models.
Heiner Dietze, Ulrike Löptien, and Julia Getzlaff
Geosci. Model Dev., 13, 71–97, https://doi.org/10.5194/gmd-13-71-2020, https://doi.org/10.5194/gmd-13-71-2020, 2020
Short summary
Short summary
We present a new near-global coupled biogeochemical ocean-circulation model configuration of the Southern Ocean. The configuration features both a relatively equilibrated oceanic carbon inventory and an explicit representation of mesoscale eddies. In this paper, we document the model configuration and showcase its potential to tackle research questions such as the Southern Ocean carbon uptake dynamics on decadal timescales.
Fabian Reith, Wolfgang Koeve, David P. Keller, Julia Getzlaff, and Andreas Oschlies
Earth Syst. Dynam., 10, 711–727, https://doi.org/10.5194/esd-10-711-2019, https://doi.org/10.5194/esd-10-711-2019, 2019
Short summary
Short summary
This modeling study is the first one to look at the suitability and collateral effects of direct CO2 injection into the deep ocean as a means to bridge the gap between CO2 emissions and climate impacts of an intermediate CO2 emission scenario and a temperature target on a millennium timescale, such as the 1.5 °C climate target of the Paris Agreement.
Tronje P. Kemena, Angela Landolfi, Andreas Oschlies, Klaus Wallmann, and Andrew W. Dale
Earth Syst. Dynam., 10, 539–553, https://doi.org/10.5194/esd-10-539-2019, https://doi.org/10.5194/esd-10-539-2019, 2019
Short summary
Short summary
Oceanic deoxygenation is driven by climate change in several areas of the global ocean. Measurements indicate that ocean volumes with very low oxygen levels expand, with consequences for marine organisms and fishery. We found climate-change-driven phosphorus (P) input in the ocean is hereby an important driver for deoxygenation on longer timescales with effects in the next millennia.
Daniela Niemeyer, Iris Kriest, and Andreas Oschlies
Biogeosciences, 16, 3095–3111, https://doi.org/10.5194/bg-16-3095-2019, https://doi.org/10.5194/bg-16-3095-2019, 2019
Short summary
Short summary
Recent studies suggest spatial variations of the marine particle flux length scale. Using a global biogeochemical ocean model, we investigate whether changes in particle size and size-dependent sinking can explain this variation. We address uncertainties by varying aggregate properties and circulation. Both aspects have an impact on the representation of nutrients, oxygen and oxygen minimum zones. The formation and sinking of large aggregates in productive areas lead to deeper flux penetration.
Henrike Schmidt, Rena Czeschel, and Martin Visbeck
Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-168, https://doi.org/10.5194/bg-2019-168, 2019
Manuscript not accepted for further review
Short summary
Short summary
Our investigations give a detailed insight on the changing current system at intermediate depth in the Arabian Sea and allow to draw conclusions on ventilation pathways of the oxygen minimum zone and its seasonal variability. In response to the monsoon system the boundary currents change direction and feature a regionally varying ventilation pattern.
Yonss Saranga José, Lothar Stramma, Sunke Schmidtko, and Andreas Oschlies
Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-155, https://doi.org/10.5194/bg-2019-155, 2019
Revised manuscript accepted for BG
Short summary
Short summary
In situ observations along the Peruvian and Chilean coasts have exhibited variability in the water column oxygen concentration. This variability, which is attributed to the El Niño Southern Oscillation (ENSO), might have implication on the vertical extension of the Eastern Tropical South Pacific (ETSP) oxygen minimum zone. Here using a coupled physical-biogeochemical model, we provide new insights into how ENSO variability affects the vertical extension of the oxygen-poor waters of the ETSP.
Robinson Hordoir, Lars Axell, Anders Höglund, Christian Dieterich, Filippa Fransner, Matthias Gröger, Ye Liu, Per Pemberton, Semjon Schimanke, Helen Andersson, Patrik Ljungemyr, Petter Nygren, Saeed Falahat, Adam Nord, Anette Jönsson, Iréne Lake, Kristofer Döös, Magnus Hieronymus, Heiner Dietze, Ulrike Löptien, Ivan Kuznetsov, Antti Westerlund, Laura Tuomi, and Jari Haapala
Geosci. Model Dev., 12, 363–386, https://doi.org/10.5194/gmd-12-363-2019, https://doi.org/10.5194/gmd-12-363-2019, 2019
Short summary
Short summary
Nemo-Nordic is a regional ocean model based on a community code (NEMO). It covers the Baltic and the North Sea area and is used as a forecast model by the Swedish Meteorological and Hydrological Institute. It is also used as a research tool by scientists of several countries to study, for example, the effects of climate change on the Baltic and North seas. Using such a model permits us to understand key processes in this coastal ecosystem and how such processes will change in a future climate.
Olaf Duteil, Andreas Oschlies, and Claus W. Böning
Biogeosciences, 15, 7111–7126, https://doi.org/10.5194/bg-15-7111-2018, https://doi.org/10.5194/bg-15-7111-2018, 2018
Short summary
Short summary
Oxygen-depleted regions of the Pacific Ocean are currently expanding, which is threatening marine habitats. Based on numerical simulations, we show that the decrease in the intensity of the trade winds and the subsequent slowdown of the oceanic currents lead to a reduction in oxygen supply. Our study suggests that the prevailing positive conditions of the Pacific Decadal Oscillation since 1975, a major source of natural variability, may explain a significant part of the current deoxygenation.
Marine Bretagnon, Aurélien Paulmier, Véronique Garçon, Boris Dewitte, Séréna Illig, Nathalie Leblond, Laurent Coppola, Fernando Campos, Federico Velazco, Christos Panagiotopoulos, Andreas Oschlies, J. Martin Hernandez-Ayon, Helmut Maske, Oscar Vergara, Ivonne Montes, Philippe Martinez, Edgardo Carrasco, Jacques Grelet, Olivier Desprez-De-Gesincourt, Christophe Maes, and Lionel Scouarnec
Biogeosciences, 15, 5093–5111, https://doi.org/10.5194/bg-15-5093-2018, https://doi.org/10.5194/bg-15-5093-2018, 2018
Short summary
Short summary
In oxygen minimum zone, the fate of the organic matter is a key question as the low oxygen condition would preserve the OM and thus enhance the biological carbon pump while the high microbial activity would foster the remineralisation and the greenhouse gases emission. To investigate this paradigm, sediment traps were deployed off Peru. We pointed out the influence of the oxygenation as well as the organic matter quantity and quality on the carbon transfer efficiency in the oxygen minimum zone.
Volkmar Sauerland, Ulrike Löptien, Claudine Leonhard, Andreas Oschlies, and Anand Srivastav
Geosci. Model Dev., 11, 1181–1198, https://doi.org/10.5194/gmd-11-1181-2018, https://doi.org/10.5194/gmd-11-1181-2018, 2018
Short summary
Short summary
We present a concept to prove that a parametric model is well calibrated, i.e., that changes of its free parameters cannot lead to a much better model–data misfit anymore. The intention is motivated by the fact that calibrating global biogeochemical ocean models is important for assessment and inter-model comparison but computationally expensive.
Nadine Mengis, David P. Keller, and Andreas Oschlies
Earth Syst. Dynam., 9, 15–31, https://doi.org/10.5194/esd-9-15-2018, https://doi.org/10.5194/esd-9-15-2018, 2018
Short summary
Short summary
The Systematic Correlation Matrix Evaluation (SCoMaE) method applies statistical information to systematically select, transparent, nonredundant indicators for a comprehensive assessment of the Earth system state. We show that due to changing climate forcing, such as anthropogenic climate change, the ad hoc assessment indicators might need to be reevaluated. Within an iterative process, this method would allow us to select scientifically consistent and societally relevant assessment indicators.
Per Pemberton, Ulrike Löptien, Robinson Hordoir, Anders Höglund, Semjon Schimanke, Lars Axell, and Jari Haapala
Geosci. Model Dev., 10, 3105–3123, https://doi.org/10.5194/gmd-10-3105-2017, https://doi.org/10.5194/gmd-10-3105-2017, 2017
Short summary
Short summary
The Baltic Sea is seasonally ice covered with intense wintertime ship traffic and a sensitive ecosystem. Understanding the sea-ice pack is important for climate effect studies and forecasting. A NEMO-LIM3.6-based model setup for the North Sea/Baltic Sea is introduced, including a method for ice in the coastal zone. We evaluate different sea-ice parameters and overall find that the model agrees well with the observation though deformed ice is more challenging to capture.
Karin F. Kvale, Samar Khatiwala, Heiner Dietze, Iris Kriest, and Andreas Oschlies
Geosci. Model Dev., 10, 2425–2445, https://doi.org/10.5194/gmd-10-2425-2017, https://doi.org/10.5194/gmd-10-2425-2017, 2017
Short summary
Short summary
Computer models of ocean biology and chemistry are becoming increasingly complex, and thus more expensive, to run. One solution is to approximate the behaviour of the ocean physics and store that information outside of the model. That
offlineinformation can then be used to calculate a steady-state solution from the model's biology and chemistry, without waiting for a traditional
onlineintegration to complete. We show this offline method reproduces online results and is 100 times faster.
James C. Orr, Raymond G. Najjar, Olivier Aumont, Laurent Bopp, John L. Bullister, Gokhan Danabasoglu, Scott C. Doney, John P. Dunne, Jean-Claude Dutay, Heather Graven, Stephen M. Griffies, Jasmin G. John, Fortunat Joos, Ingeborg Levin, Keith Lindsay, Richard J. Matear, Galen A. McKinley, Anne Mouchet, Andreas Oschlies, Anastasia Romanou, Reiner Schlitzer, Alessandro Tagliabue, Toste Tanhua, and Andrew Yool
Geosci. Model Dev., 10, 2169–2199, https://doi.org/10.5194/gmd-10-2169-2017, https://doi.org/10.5194/gmd-10-2169-2017, 2017
Short summary
Short summary
The Ocean Model Intercomparison Project (OMIP) is a model comparison effort under Phase 6 of the Coupled Model Intercomparison Project (CMIP6). Its physical component is described elsewhere in this special issue. Here we describe its ocean biogeochemical component (OMIP-BGC), detailing simulation protocols and analysis diagnostics. Simulations focus on ocean carbon, other biogeochemical tracers, air-sea exchange of CO2 and related gases, and chemical tracers used to evaluate modeled circulation.
Daniela Niemeyer, Tronje P. Kemena, Katrin J. Meissner, and Andreas Oschlies
Earth Syst. Dynam., 8, 357–367, https://doi.org/10.5194/esd-8-357-2017, https://doi.org/10.5194/esd-8-357-2017, 2017
Markus Schartau, Philip Wallhead, John Hemmings, Ulrike Löptien, Iris Kriest, Shubham Krishna, Ben A. Ward, Thomas Slawig, and Andreas Oschlies
Biogeosciences, 14, 1647–1701, https://doi.org/10.5194/bg-14-1647-2017, https://doi.org/10.5194/bg-14-1647-2017, 2017
Short summary
Short summary
Plankton models have become an integral part in marine ecosystem and biogeochemical research. These models differ in complexity and in their number of parameters. How values are assigned to parameters is essential. An overview of major methodologies of parameter estimation is provided. Aspects of parameter identification in the literature are diverse. Individual findings could be better synthesized if notation and expertise of the different scientific communities would be reasonably merged.
Heiner Dietze, Julia Getzlaff, and Ulrike Löptien
Biogeosciences, 14, 1561–1576, https://doi.org/10.5194/bg-14-1561-2017, https://doi.org/10.5194/bg-14-1561-2017, 2017
Short summary
Short summary
The Southern Ocean is a sink for anthropogenic carbon. Projections of how this sink will evolve in an ever-warming climate are based on coupled ocean-circulation–biogeochemical models. This study compares uncertainties of simulated oceanic carbon uptake associated to physical (eddy) parameterizations with those associated wtih (unconstrained) supply of bioavailable iron supply to the surface ocean.
Yonss Saranga José, Heiner Dietze, and Andreas Oschlies
Biogeosciences, 14, 1349–1364, https://doi.org/10.5194/bg-14-1349-2017, https://doi.org/10.5194/bg-14-1349-2017, 2017
Short summary
Short summary
This study aims to investigate the diverse subsurface nutrient patterns observed within anticyclonic eddies in the upwelling system off Peru. Two simulated anticyclonic eddies with opposing subsurface nitrate concentrations were analysed. The results show that diverse nutrient patterns within anticyclonic eddies are related to the presence of water mass from different origins at different depths, responding to variations in depth of the circulation strength at the edge of the eddy.
Iris Kriest, Volkmar Sauerland, Samar Khatiwala, Anand Srivastav, and Andreas Oschlies
Geosci. Model Dev., 10, 127–154, https://doi.org/10.5194/gmd-10-127-2017, https://doi.org/10.5194/gmd-10-127-2017, 2017
Short summary
Short summary
Global biogeochemical ocean models are subject to a high level of parametric uncertainty. This may be of consequence for their skill with respect to accurately describing features of the present ocean and their sensitivity to possible environmental changes. We present the first results from a framework that combines an offline biogeochemical tracer transport model with an estimation of distribution algorithm, calibrating six biogeochemical model parameters against observed oxygen and nutrients.
Fabian Reith, David P. Keller, and Andreas Oschlies
Earth Syst. Dynam., 7, 797–812, https://doi.org/10.5194/esd-7-797-2016, https://doi.org/10.5194/esd-7-797-2016, 2016
Bei Su, Markus Pahlow, and Andreas Oschlies
Biogeosciences, 13, 4985–5001, https://doi.org/10.5194/bg-13-4985-2016, https://doi.org/10.5194/bg-13-4985-2016, 2016
Short summary
Short summary
Previously identified positive feedbacks within the nitrogen cycle in the eastern tropical South Pacific (ETSP) have challenged our understanding of the observed dynamics and stability of the nitrogen inventory. We present a box model analysis of the biological and biogeochemical relations in the ETSP among nitrogen deposition, benthic denitrification and phosphate regeneration. Our results suggest dominant stabilizing feedbacks tending to keep a balanced nitrogen inventory in the ETSP.
Heiner Dietze and Ulrike Löptien
Ocean Sci., 12, 977–986, https://doi.org/10.5194/os-12-977-2016, https://doi.org/10.5194/os-12-977-2016, 2016
Short summary
Short summary
Winds blowing over the ocean drive ocean currents. The oceanic response to winds is, in turn, influenced by ocean currents. Theoretical considerations suggest that the latter effect is especially pronounced in the Baltic Sea. The study presented here puts theses theoretical considerations in a high-resolution ocean circulation model of the Baltic Sea to the test.
I. Kriest and A. Oschlies
Geosci. Model Dev., 8, 2929–2957, https://doi.org/10.5194/gmd-8-2929-2015, https://doi.org/10.5194/gmd-8-2929-2015, 2015
Short summary
Short summary
We use a global model of oceanic P, N, and O2 cycles to investigate consequences of uncertainties in description of organic matter sinking, remineralization, denitrification, and N2-Fixation. After all biogeochemical and physical processes have been spun-up into a dynamically consistent steady-state, particle sinking and oxidant affinities of aerobic and anaerobic remineralization determine the extent of oxygen minimum zones, global nitrogen fluxes, and the oceanic nitrogen inventory.
U. Löptien and H. Dietze
Ocean Sci., 11, 573–590, https://doi.org/10.5194/os-11-573-2015, https://doi.org/10.5194/os-11-573-2015, 2015
Short summary
Short summary
Marine biogeochemical ocean models are embedded into earth system models - which are, to an increasing degree, applied to project the fate of our warming world. These biogeochemical models generally depend on poorly constrained model parameters. In this study we investigate the the demands on observations for an objective estimation of such parameters. A major result is that even modest noise (10%) inherent to observations can hinder the assignment of reasonable parameters.
W. Koeve, H. Wagner, P. Kähler, and A. Oschlies
Geosci. Model Dev., 8, 2079–2094, https://doi.org/10.5194/gmd-8-2079-2015, https://doi.org/10.5194/gmd-8-2079-2015, 2015
Short summary
Short summary
The natural abundance of 14C in CO2 dissolved in seawater is often used to evaluate circulation and age in the ocean and in ocean models. We study limitations of using natural 14C to determine the time elapsed since water had contact with the atmosphere. We find that, globally, bulk 14C age is dominated by two equally important components, (1) the time component of circulation and (2) the “preformed 14C-age”. Considering preformed 14C-age is critical for an assessment of circulation in models.
L. Nickelsen, D. P. Keller, and A. Oschlies
Geosci. Model Dev., 8, 1357–1381, https://doi.org/10.5194/gmd-8-1357-2015, https://doi.org/10.5194/gmd-8-1357-2015, 2015
Short summary
Short summary
In this paper we find that including the marine cycle of the phytoplankton nutrient iron in a global climate model improves the agreement between observed and simulated nutrient concentrations in the ocean and that a better description of the source of iron from the sediment to the ocean is more important than that of iron-containing dust deposition. Finally, we find that the response of the iron cycle to climate warming affects the phytoplankton growth and nutrient cycles.
B. Su, M. Pahlow, H. Wagner, and A. Oschlies
Biogeosciences, 12, 1113–1130, https://doi.org/10.5194/bg-12-1113-2015, https://doi.org/10.5194/bg-12-1113-2015, 2015
Short summary
Short summary
A box model of the eastern tropical South Pacific oxygen minimum zone suggests that anaerobic water-column remineralization rates have to be slower than aerobic remineralization in order to explain the relatively high values of observed nitrate concentrations. Lateral oxygen supply sufficient to oxidize about one-fifth of the export production is required to prevent an anoxic deep ocean. Under these circumstances, the region can be a net source of fixed nitrogen to the surrounding ocean.
U. Löptien and L. Axell
The Cryosphere, 8, 2409–2418, https://doi.org/10.5194/tc-8-2409-2014, https://doi.org/10.5194/tc-8-2409-2014, 2014
Short summary
Short summary
The Baltic Sea is a seasonally ice-covered marginal sea in central northern Europe. In wintertime, on-time shipping depends crucially on sea ice forecasts. Among the forecasting tools heavily applied are numerical models, which suffer from a lack of calibration data because relevant ice properties are difficult (and costly) to monitor. We developed an innovative and inexpensive approach, by using ship speed observations obtained by the automatic identification system (AIS) to asses such models.
U. Löptien and H. Dietze
Earth Syst. Sci. Data, 6, 367–374, https://doi.org/10.5194/essd-6-367-2014, https://doi.org/10.5194/essd-6-367-2014, 2014
W. Koeve, O. Duteil, A. Oschlies, P. Kähler, and J. Segschneider
Geosci. Model Dev., 7, 2393–2408, https://doi.org/10.5194/gmd-7-2393-2014, https://doi.org/10.5194/gmd-7-2393-2014, 2014
H. Dietze, U. Löptien, and K. Getzlaff
Geosci. Model Dev., 7, 1713–1731, https://doi.org/10.5194/gmd-7-1713-2014, https://doi.org/10.5194/gmd-7-1713-2014, 2014
A. E. F. Prowe, M. Pahlow, S. Dutkiewicz, and A. Oschlies
Biogeosciences, 11, 3397–3407, https://doi.org/10.5194/bg-11-3397-2014, https://doi.org/10.5194/bg-11-3397-2014, 2014
I. Kriest and A. Oschlies
Biogeosciences, 10, 8401–8422, https://doi.org/10.5194/bg-10-8401-2013, https://doi.org/10.5194/bg-10-8401-2013, 2013
O. Duteil, W. Koeve, A. Oschlies, D. Bianchi, E. Galbraith, I. Kriest, and R. Matear
Biogeosciences, 10, 7723–7738, https://doi.org/10.5194/bg-10-7723-2013, https://doi.org/10.5194/bg-10-7723-2013, 2013
C. J. Somes, A. Oschlies, and A. Schmittner
Biogeosciences, 10, 5889–5910, https://doi.org/10.5194/bg-10-5889-2013, https://doi.org/10.5194/bg-10-5889-2013, 2013
V. Cocco, F. Joos, M. Steinacher, T. L. Frölicher, L. Bopp, J. Dunne, M. Gehlen, C. Heinze, J. Orr, A. Oschlies, B. Schneider, J. Segschneider, and J. Tjiputra
Biogeosciences, 10, 1849–1868, https://doi.org/10.5194/bg-10-1849-2013, https://doi.org/10.5194/bg-10-1849-2013, 2013
A. Landolfi, H. Dietze, W. Koeve, and A. Oschlies
Biogeosciences, 10, 1351–1363, https://doi.org/10.5194/bg-10-1351-2013, https://doi.org/10.5194/bg-10-1351-2013, 2013
M. El Jarbi, J. Rückelt, T. Slawig, and A. Oschlies
Biogeosciences, 10, 1169–1182, https://doi.org/10.5194/bg-10-1169-2013, https://doi.org/10.5194/bg-10-1169-2013, 2013
L. M. Zamora, A. Oschlies, H. W. Bange, K. B. Huebert, J. D. Craig, A. Kock, and C. R. Löscher
Biogeosciences, 9, 5007–5022, https://doi.org/10.5194/bg-9-5007-2012, https://doi.org/10.5194/bg-9-5007-2012, 2012
Cited articles
Adachi, Y., Yukimoto, S., Deushi, M., Obata, A., Nakano, H., Tanaka, T. Y.,
Hosaka, M., Sakami, T., Yoshimura, H., Hirabara, M., Shindo, E., Tsujino, H.,
Mizuta, R., Yabu, S., Koshiro, T., Ose, T., and Kitoh, A.: Basic performance
of a new earth system model of the Meteorological Research Institute, Papers
in Meteorology and Geophysics, 64, 1–19, https://doi.org/10.2467/mripapers.64.1, 2013. a, b
Assmann, K. M., Bentsen, M., Segschneider, J., and Heinze, C.: An isopycnic ocean carbon cycle model, Geosci. Model Dev., 3, 143–167, https://doi.org/10.5194/gmd-3-143-2010, 2010. a
Aumont, O. and Bopp, L.: Globalizing results from ocean in situ iron
fertilization studies, Global Biogeochem. Cy., 20, 1–15,
https://doi.org/10.1029/2005GB002591, 2006. a, b
Beal, L. M., Ffield, A., and Gordon, A. L.: Spreading of Red Sea overflow
waters in the Indian Ocean, J. Geophys. Res., 105,
8549–8564, https://doi.org/10.1029/1999JC900306,
2000. a
Beal, L. M., Hormann, V., Lumpkin, R., and Foltz, G. R.: The Response of the
Surface Circulation of the Arabian Sea to Monsoonal Forcing, J. Phys. Oceanogr., 43, 2008–2022, https://doi.org/10.1175/JPO-D-13-033.1,
2013. a
Bentsen, M., Bethke, I., Debernard, J. B., Iversen, T., Kirkevåg, A., Seland, Ø., Drange, H., Roelandt, C., Seierstad, I. A., Hoose, C., and Kristjánsson, J. E.: The Norwegian Earth System Model, NorESM1-M – Part 1: Description and basic evaluation of the physical climate, Geosci. Model Dev., 6, 687–720, https://doi.org/10.5194/gmd-6-687-2013, 2013. a
Bopp, L., Resplandy, L., Orr, J. C., Doney, S. C., Dunne, J. P., Gehlen, M., Halloran, P., Heinze, C., Ilyina, T., Séférian, R., Tjiputra, J., and Vichi, M.: Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models, Biogeosciences, 10, 6225–6245, https://doi.org/10.5194/bg-10-6225-2013, 2013. a, b, c, d, e
Breitburg, D., Levin, L. A., Oschlies, A., Grégoire, M., Chavez, F. P.,
Conley, D. J., Garçon, V., Gilbert, D., Gutiérrez, D., Isensee,
K., Jacinto, G. S., Limburg, K. E., Montes, I., Naqvi, S. W., Pitcher, G. C.,
Rabalais, N. N., Roman, M. R., Rose, K. A., Seibel, B. A., Telszewski, M.,
Yasuhara, M., and Zhang, J.: Declining oxygen in the global ocean and
coastal waters, Science, 359, eaam7240, https://doi.org/10.1126/science.aam7240, 2018. a
Cocco, V., Joos, F., Steinacher, M., Frölicher, T. L., Bopp, L., Dunne, J., Gehlen, M., Heinze, C., Orr, J., Oschlies, A., Schneider, B., Segschneider, J., and Tjiputra, J.: Oxygen and indicators of stress for marine life in multi-model global warming projections, Biogeosciences, 10, 1849–1868, https://doi.org/10.5194/bg-10-1849-2013, 2013. a, b, c
Danabasoglu, G., Bates, S. C., Briegleb, B. P., Jayne, S. R., Jochum, M.,
Large, W. G., Peacock, S., and Yeager, S. G.: The CCSM4 ocean component,
J. Climate, 25, 1361–1389, https://doi.org/10.1175/JCLI-D-11-00091.1, 2012. a
De Amorim, R. C. and Hennig, C.: Recovering the number of clusters in data
sets with noise features using feature rescaling factors, Information
Sciences, 324, 126–145, https://doi.org/10.1016/j.ins.2015.06.039,
2015. a
Diaz, R. J. and Rosenberg, R.: Spreading Dead Zones and Consequences for
Marine Ecosystems, Science, 321, 926–930, https://doi.org/10.1126/science.1156401,
2008. a, b
Dufresne, J. L., Foujols, M. A., Denvil, S., Caubel, A., Marti, O., Aumont, O.,
Balkanski, Y., Bekki, S., Bellenger, H., Benshila, R., Bony, S., Bopp, L.,
Braconnot, P., Brockmann, P., Cadule, P., Cheruy, F., Codron, F., Cozic, A.,
Cugnet, D., de Noblet, N., Duvel, J. P., Ethé, C., Fairhead, L.,
Fichefet, T., Flavoni, S., Friedlingstein, P., Grandpeix, J. Y., Guez, L.,
Guilyardi, E., Hauglustaine, D., Hourdin, F., Idelkadi, A., Ghattas, J.,
Joussaume, S., Kageyama, M., Krinner, G., Labetoulle, S., Lahellec, A.,
Lefebvre, M. P., Lefevre, F., Levy, C., Li, Z. X., Lloyd, J., Lott, F.,
Madec, G., Mancip, M., Marchand, M., Masson, S., Meurdesoif, Y., Mignot, J.,
Musat, I., Parouty, S., Polcher, J., Rio, C., Schulz, M., Swingedouw, D.,
Szopa, S., Talandier, C., Terray, P., Viovy, N., and Vuichard, N.: Climate
change projections using the IPSL-CM5 Earth System Model: From CMIP3 to
CMIP5, Clim. Dynam., 40, 2123–2165, https://doi.org/10.1007/s00382-012-1636-1, 2013. a, b
Dunne, J. P., John, J. G., Adcroft, A. J., Griffies, S. M., Hallberg, R. W.,
Shevliakova, E., Stouffer, R. J., Cooke, W., Dunne, K. A., Harrison, M. J.,
Krasting, J. P., Malyshev, S. L., Milly, P. C., Phillipps, P. J., Sentman,
L. T., Samuels, B. L., Spelman, M. J., Winton, M., Wittenberg, A. T., and
Zadeh, N.: GFDL's ESM2 global coupled climate-carbon earth system models,
Part I: Physical formulation and baseline simulation characteristics,
J. Climate, 25, 6646–6665, https://doi.org/10.1175/JCLI-D-11-00560.1, 2012. a, b
Dunne, J. P., John, J. G., Shevliakova, S., Stouffer, R. J., Krasting, J. P.,
Malyshev, S. L., Milly, P. C., Sentman, L. T., Adcroft, A. J., Cooke, W.,
Dunne, K. A., Griffies, S. M., Hallberg, R. W., Harrison, M. J., Levy, H.,
Wittenberg, A. T., Phillips, P. J., and Zadeh, N.: GFDL's ESM2 global
coupled climate-carbon earth system models. Part II: Carbon system
formulation and baseline simulation characteristics, J. Climate, 26,
2247–2267, https://doi.org/10.1175/JCLI-D-12-00150.1, 2013. a, b
ESGF: Earth System Grid Federation, World Climate Research Programme, CMIP5 Project data download, [data set], available at: https://esgf-node.llnl.gov/projects/cmip5/, last access: 20 July 2019. a
Gent, P. R., Danabasoglu, G., Donner, L. J., Holland, M. M., Hunke, E. C.,
Jayne, S. R., Lawrence, D. M., Neale, R. B., Rasch, P. J., Vertenstein, M.,
Worley, P. H., Yang, Z. L., and Zhang, M.: The community climate system
model version 4, J. Climate, 24, 4973–4991,
https://doi.org/10.1175/2011JCLI4083.1, 2011. a
Giorgetta, M. A., Jungclaus, J., Reick, C. H., Legutke, S., Bader, J.,
Böttinger, M., Brovkin, V., Crueger, T., Esch, M., Fieg, K., Glushak,
K., Gayler, V., Haak, H., Hollweg, H.-D., Ilyina, T., Kinne, S., Kornblueh,
L., Matei, D., Mauritsen, T., Mikolajewicz, U., Mueller, W., Notz, D.,
Pithan, F., Raddatz, T., Rast, S., Redler, R., Roeckner, E., Schmidt, H.,
Schnur, R., Segschneider, J., Six, K. D., Stockhause, M., Timmreck, C.,
Wegner, J., Widmann, H., Wieners, K.-H., Claussen, M., Marotzke, J., and
Stevens, B.: Climate and carbon cycle changes from 1850 to 2100 in MPI-ESM
simulations for the Coupled Model Intercomparison Project phase 5, J. Adv. Model. Earth Sys., 5, 572–597, https://doi.org/10.1002/jame.20038,
2013. a, b
Halloran, P. R., Bell, T. G., and Totterdell, I. J.: Can we trust empirical marine DMS parameterisations within projections of future climate?, Biogeosciences, 7, 1645–1656, https://doi.org/10.5194/bg-7-1645-2010, 2010. a
Hood, R. R., Beckley, L. E., and Wiggert, J. D.: Biogeochemical and ecological
impacts of boundary currents in the Indian Ocean, Prog. Oceanogr.,
156, 290–325, https://doi.org/10.1016/j.pocean.2017.04.011,
2017. a
Ilyina, T., Six, K. D., Segschneider, J., Maier-Reimer, E., Li, H., and
Núñez-Riboni, I.: Global ocean biogeochemistry model HAMOCC:
Model architecture and performance as component of the MPI-Earth system model
in different CMIP5 experimental realizations, J. Adv. Model. Earth Sys., 5, 287–315, https://doi.org/10.1029/2012MS000178, 2013. a, b
Ito, T., Minobe, S., Long, M. C., and Deutsch, C.: Upper ocean O2 trends:
1958–2015, Geophys. Res. Lett., 44, 4214–4223,
https://doi.org/10.1002/2017GL073613, 2017. a
Jenkins, W. J.: Tritium-Helium Dating in the Sargasso Sea: A Measurement of
Oxygen Utilization Rates, Science, 196, 291–292, https://doi.org/10.1126/science.196.4287.291, 1977. a
Johnson, S. C.: Hierarchical clustering schemes, Psychometrika, 32, 241–254,
https://doi.org/10.1007/BF02289588, 1967. a
Jones, C. D., Hughes, J. K., Bellouin, N., Hardiman, S. C., Jones, G. S., Knight, J., Liddicoat, S., O'Connor, F. M., Andres, R. J., Bell, C., Boo, K.-O., Bozzo, A., Butchart, N., Cadule, P., Corbin, K. D., Doutriaux-Boucher, M., Friedlingstein, P., Gornall, J., Gray, L., Halloran, P. R., Hurtt, G., Ingram, W. J., Lamarque, J.-F., Law, R. M., Meinshausen, M., Osprey, S., Palin, E. J., Parsons Chini, L., Raddatz, T., Sanderson, M. G., Sellar, A. A., Schurer, A., Valdes, P., Wood, N., Woodward, S., Yoshioka, M., and Zerroukat, M.: The HadGEM2-ES implementation of CMIP5 centennial simulations, Geosci. Model Dev., 4, 543–570, https://doi.org/10.5194/gmd-4-543-2011, 2011. a
Jungclaus, J. H., Fischer, N., Haak, H., Lohmann, K., Marotzke, J., Matei, D.,
Mikolajewicz, U., Notz, D., and Von Storch, J. S.: Characteristics of the
ocean simulations in the Max Planck Institute Ocean Model (MPIOM) the ocean
component of the MPI-Earth system model, J. Adv. Model. Earth Sys., 5, 422–446, https://doi.org/10.1002/jame.20023, 2013. a, b
Kamykowski, D. and Zentara, S. J.: Hypoxia in the world ocean as recorded in
the historical data set, Deep Sea Res., 37, 1861–1874, https://doi.org/10.1016/0198-0149(90)90082-7, 1990. a, b, c
Karstensen, J., Stramma, L., and Visbeck, M.: Oxygen minimum zones in the
eastern tropical Atlantic and Pacific oceans, Prog. Oceanogr., 77,
331–350, https://doi.org/10.1016/j.pocean.2007.05.009, 2008. a
Keeling, R. E., Körtzinger, A., and Gruber, N.: Ocean deoxygenation in a
warming world., Annu. Rev. Mar. Sci., 2, 199–229,
https://doi.org/10.1146/annurev.marine.010908.163855, 2010. a, b, c, d
Kwiatkowski, L., Torres, O., Bopp, L., Aumont, O., Chamberlain, M., Christian, J. R., Dunne, J. P., Gehlen, M., Ilyina, T., John, J. G., Lenton, A., Li, H., Lovenduski, N. S., Orr, J. C., Palmieri, J., Santana-Falcón, Y., Schwinger, J., Séférian, R., Stock, C. A., Tagliabue, A., Takano, Y., Tjiputra, J., Toyama, K., Tsujino, H., Watanabe, M., Yamamoto, A., Yool, A., and Ziehn, T.: Twenty-first century ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary production decline from CMIP6 model projections, Biogeosciences, 17, 3439–3470, https://doi.org/10.5194/bg-17-3439-2020, 2020. a, b, c, d
Lachkar, Z., Smith, S., Levy, M., Pauluis, O., Lévy, M., and Pauluis, O.:
Eddies reduce denitrification and compress habitats in the Arabian Sea,
Geophys. Res. Lett., 43, 1–17, https://doi.org/10.1002/2016GL069876,
2016. a, b
Levin, L. A., Whitcraft, C. R., Mendoza, G. F., and Gonzalez, J. P.: Oxygen
and organic matter thresholds for benthic faunal activity on the Pakistan
margin oxygen minimum zone (700–1100 m), Deep-Sea Res. Pt. II, 56, 449–471, https://doi.org/10.1016/j.dsr2.2008.05.032,
2009. a
Löptien, U. and Dietze, H.: Reciprocal bias compensation and ensuing uncertainties in model-based climate projections: pelagic biogeochemistry versus ocean mixing, Biogeosciences, 16, 1865–1881, https://doi.org/10.5194/bg-16-1865-2019, 2019. a
McCartney, M. and Woodgate-Jones, M.: A deep-reaching anticyclonic eddy in the
subtropical gyre of the eastern South Atlantic, Deep Sea Res.,
38, 411–443,
https://doi.org/10.1016/s0198-0149(12)80019-7, 1991. a
McCreary, J. P., Yu, Z., Hood, R. R., Vinaychandran, P. N., Furue, R., Ishida,
A., and Richards, K. J.: Dynamics of the Indian-Ocean oxygen minimum zones,
Prog. Oceanogr., 112, 15–37,
https://doi.org/10.1016/j.pocean.2013.03.002,
2013. a
Mignot, J., Swingedouw, D., Deshayes, J., Marti, O., Talandier, C.,
Séférian, R., Lengaigne, M., and Madec, G.: On the evolution of
the oceanic component of the IPSL climate models from CMIP3 to CMIP5: A mean
state comparison, Ocean Model., 72, 167–184,
https://doi.org/10.1016/j.ocemod.2013.09.001, 2013. a
Moore, J. K., Doney, S. C., and Lindsay, K.: Upper ocean ecosystem dynamics
and iron cycling in a global three-dimensional model, Global Biogeochem. Cy., 18, 1–21, https://doi.org/10.1029/2004GB002220, 2004. a
NOAA: National Oceanic and Atmospheric Administration,
WOA13 temperature, salinity and oxygen, [data set], available at: https://www.nodc.noaa.gov/cgi-bin/OC5/woa13/woa13oxnu.pl; https://www.nodc.noaa.gov/cgi-bin/OC5/woa13/woa13.pl, last access:
15 June 2020. a
Oschlies, A., Schulz, K. G., Riebesell, U., and Schmittner, A.: Simulated 21st
century's increase in oceanic suboxia by CO2-enhanced biotic carbon export,
Global Biogeochem. Cy., 22, 1–10, https://doi.org/10.1029/2007GB003147, 2008. a
Oschlies, A., Duteil, O., Getzlaff, J., Koeve, W., Landolfi, A., and Schmidtko,
S.: Patterns of deoxygenation: sensitivity to natural and anthropogenic
drivers, Philos. T. Roy. Soc. A, 375, 20160325, https://doi.org/10.1098/rsta.2016.0325,
2017. a, b, c
Oschlies, A., Brandt, P., Stramma, L., and Schmidtko, S.: Drivers and
mechanisms of ocean deoxygenation, Nat. Geosci., 11, 467–473,
https://doi.org/10.1038/s41561-018-0152-2,
2018. a, b
Palmer, J. R. and Totterdell, I. J.: Production and export in a global ocean
ecosystem model, Deep-Sea Res. Pt. I
48, 1169–1198, https://doi.org/10.1016/S0967-0637(00)00080-7, 2001. a
Prasad, T. G., Ikeda, M., and Kumar, S. P.: Seasonal spreading of the Persian
Gulf Water mass in the Arabian Sea, J. Geophys. Res., 106,
17059–17071, https://doi.org/10.1029/2000JC000480,
2001. a
Rao, C. K., Naqvi, S. W., Kumar, M. D., Varaprasad, S. J., Jayakumar, D. A.,
George, M. D., and Singbal, S. Y.: Hydrochemistry of the Bay of Bengal:
possible reasons for a different water-column cycling of carbon and nitrogen
from the Arabian Sea, Mar. Chem., 47, 279–290,
https://doi.org/10.1016/0304-4203(94)90026-4, 1994. a, b, c, d, e
Resplandy, L., Lévy, M., Bopp, L., Echevin, V., Pous, S., Sarma, V. V. S. S., and Kumar, D.: Controlling factors of the oxygen balance in the Arabian Sea's OMZ, Biogeosciences, 9, 5095–5109, https://doi.org/10.5194/bg-9-5095-2012, 2012. a, b, c
Rixen, T. and Ittekkot, V.: Nitrogen deficits in the Arabian Sea, implications
from a three component mixing analysis, Deep-Sea Res. Pt. II, 52, 1879–1891,
https://doi.org/10.1016/j.dsr2.2005.06.007,
2005. a
Rixen, T., Cowie, G., Gaye, B., Goes, J., do Rosário Gomes, H., Hood, R. R., Lachkar, Z., Schmidt, H., Segschneider, J., and Singh, A.: Reviews and syntheses: Present, past, and future of the oxygen minimum zone in the northern Indian Ocean, Biogeosciences, 17, 6051–6080, https://doi.org/10.5194/bg-17-6051-2020, 2020. a
Sallée, J. B., Shuckburgh, E., Bruneau, N., Meijers, A. J., Bracegirdle,
T. J., and Wang, Z.: Assessment of Southern Ocean mixed-layer depths in
CMIP5 models: Historical bias and forcing response, J. Geophys. Res.-Oceans, 118, 1845–1862, https://doi.org/10.1002/jgrc.20157,
2013a. a
Sallée, J. B., Shuckburgh, E., Bruneau, N., Meijers, A. J., Bracegirdle,
T. J., Wang, Z., and Roy, T.: Assessment of Southern Ocean water mass
circulation and characteristics in CMIP5 models: Historical bias and forcing
response, J. Geophys. Res.-Oceans, 118, 1830–1844,
https://doi.org/10.1002/jgrc.20135, 2013b. a, b, c, d, e, f, g, h
Schmidt, H., Getzlaff, J., Löptien, U., and Oschlies, A.,: Causes of uncertainties in the representation of the Arabian Sea oxygen minimum zone in CMIP5 models, [code], available at: https://oceanrep.geomar.de/52412/, last access: 17 May 2021. a
Schmidtko, S., Stramma, L., and Visbeck, M.: Decline in global oceanic oxygen
content during the past five decades, Nature, 542, 335–339,
https://doi.org/10.1038/nature21399, 2017. a
Séférian, R., Bopp, L., Gehlen, M., Orr, J. C., Ethé, C.,
Cadule, P., Aumont, O., Salas y Mélia, D., Voldoire, A., and Madec,
G.: Skill assessment of three earth system models with common marine
biogeochemistry, Clim. Dynam., 40, 2549–2573,
https://doi.org/10.1007/s00382-012-1362-8, 2013. a, b
Séférian, R., Gehlen, M., Bopp, L., Resplandy, L., Orr, J. C., Marti, O., Dunne, J. P., Christian, J. R., Doney, S. C., Ilyina, T., Lindsay, K., Halloran, P. R., Heinze, C., Segschneider, J., Tjiputra, J., Aumont, O., and Romanou, A.: Inconsistent strategies to spin up models in CMIP5: implications for ocean biogeochemical model performance assessment, Geosci. Model Dev., 9, 1827–1851, https://doi.org/10.5194/gmd-9-1827-2016, 2016. a
Séférian, R., Berthet, S., Yool, A., Palmiéri, J., Bopp, L.,
Tagliabue, A., Kwiatkowski, L., Aumont, O., Christian, J., Dunne, J., Gehlen,
M., Ilyina, T., John, J. G., Li, H., Long, M. C., Luo, J. Y., Nakano, H.,
Romanou, A., Schwinger, J., Stock, C., Santana-Falcón, Y., Takano, Y.,
Tjiputra, J., Tsujino, H., Watanabe, M., Wu, T., Wu, F., and Yamamoto, A.:
Tracking Improvement in Simulated Marine Biogeochemistry Between CMIP5 and
CMIP6, Current Climate Change Reports, 6, 95–119,
https://doi.org/10.1007/s40641-020-00160-0, 2020. a, b, c, d
Segschneider, J. and Bendtsen, J.: Temperature-dependent remineralization in a
warming ocean increases surface pCO2 through changes in marine ecosystem
composition, Global Biogeochem. Cy., 27, 1214–1225,
https://doi.org/10.1002/2013GB004684, 2013. a
Seland, Ø., Bentsen, M., Olivié, D., Toniazzo, T., Gjermundsen, A., Graff, L. S., Debernard, J. B., Gupta, A. K., He, Y.-C., Kirkevåg, A., Schwinger, J., Tjiputra, J., Aas, K. S., Bethke, I., Fan, Y., Griesfeller, J., Grini, A., Guo, C., Ilicak, M., Karset, I. H. H., Landgren, O., Liakka, J., Moseid, K. O., Nummelin, A., Spensberger, C., Tang, H., Zhang, Z., Heinze, C., Iversen, T., and Schulz, M.: Overview of the Norwegian Earth System Model (NorESM2) and key climate response of CMIP6 DECK, historical, and scenario simulations, Geosci. Model Dev., 13, 6165–6200, https://doi.org/10.5194/gmd-13-6165-2020, 2020. a
Shankar, D., Shenoi, S. S. C., Nayak, R. K., Vinayachandran, P. N.,
Nampoothiri, G., Almeida, A. M., Michael, G. S., Kumar, M. R. R., Sundar, D.,
and Sreejith, O. P.: Hydrography of the eastern Arabian Sea during summer
monsoon 2002, J. Earth Sys. Sci., 114, 459–474,
https://doi.org/10.1007/BF02702023, 2005. a
Sharma, G.: Upwelling Off the Southwest Coast of India, Indian Journal of
Geo-Marine Sciences (IJMS), 07, 209–218, 1978. a
Shenoi, S. S. C., Saji, P. K., and Almeida, A. M.: Near-surface circulation
and kinetic energy in the tropical Indian Ocean derived from Lagrangian
drifters, J. Mar. Res., 57, 885–907,
https://doi.org/10.1357/002224099321514088,
1999. a
Shenoy, D. M., Suresh, I., Uskaikar, H., Kurian, S., Vidya, P. J., Shirodkar,
G., Gauns, M. U., and Naqvi, S. W.: Variability of dissolved oxygen in the
Arabian Sea Oxygen Minimum Zone and its driving mechanisms, J.
Mar. Sys., 204, 103310, https://doi.org/10.1016/j.jmarsys.2020.103310,
2020. a
Shetye, S. R., Gouveia, A. D., Shenoi, S. S. C., Sundar, D., Michael, G. S.,
Almeida, A. M., and Santanam, K.: Hydrography and circulation off the west
coast of India during the Southwest Monsoon 1987, J. Mar. Res., 48, 359–378, https://doi.org/10.1357/002224090784988809, 1990. a
Sprintall, J. and Tomczak, M.: On the formation of central water and
thermocline ventilation in the southern hemisphere, Deep-Sea Res. Pt. I, 40, 827–848, https://doi.org/10.1016/0967-0637(93)90074-D, 1993. a, b, c
Stramma, L., Brandt, P., Schott, F., Quadfasel, D., and Fischer, J.: Winter
and summer monsoon water mass, heat and freshwater transport changes in the
Arabian Sea near 8∘ N, Deep-Sea Res. Pt. II, 49, 1173–1195, https://doi.org/10.1016/S0967-0645(01)00169-2, 2002. a, b
Stramma, L., Schmidtko, S., Levin, L. A., and Johnson, G. C.: Ocean oxygen
minima expansions and their biological impacts, Deep-Sea Res. Pt. I, 57, 587–595, https://doi.org/10.1016/j.dsr.2010.01.005,
2010. a
Stramma, L., Oschlies, A., and Schmidtko, S.: Mismatch between observed and modeled trends in dissolved upper-ocean oxygen over the last 50 yr, Biogeosciences, 9, 4045–4057, https://doi.org/10.5194/bg-9-4045-2012, 2012.
a, b
Suess, E.: Particulate organic carbon flux in the oceans - Surface
productivity and oxygen utilization, Nature, 288, 260–263,
https://doi.org/10.1038/288260a0, 1980. a
Sverdrup, H. U.: On the explanation of the oxygen minima and maxima in the
oceans, ICES J. Mar. Sci., 13, 163–172,
https://doi.org/10.1093/icesjms/13.2.163, 1938. a, b
Tagklis, F., Ito, T., and Bracco, A.: Modulation of the North Atlantic deoxygenation by the slowdown of the nutrient stream, Biogeosciences, 17, 231–244, https://doi.org/10.5194/bg-17-231-2020, 2020. a
Talley, L. D., Pickard, G. L., Emery, W. J., and Swift, J. H.: Chapter 10 –
Pacific Ocean, in: Descriptive Physical Oceanography (Sixth Edition), edited
by: Talley, L. D., Pickard, G. L., Emery, W. J., and Swift, J. H., Chap. 10, Academic Press, sixth edit edn., 303–362,
https://doi.org/10.1016/B978-0-7506-4552-2.10010-1,
2011a. a
Talley, L. D., Pickard, G. L., Emery, W. J., and Swift, J. H.: Chapter 11 –
Indian Ocean, in: Descriptive Physical Oceanography (Sixth Edition), edited
by Talley, L. D., Pickard, G. L., Emery, W. J., and Swift, J. H., Chap. 11, sixth edit edn., 363–399,
https://doi.org/10.1016/B978-0-7506-4552-2.10010-1, 2011b. a
Taylor, K. E., Stouffer, R. J., and Meehl, G. A.: An overview of CMIP5 and the
experiment design, B. Am. Meteorol. Soc., 93,
485–498, https://doi.org/10.1175/BAMS-D-11-00094.1, 2012. a, b
Tomczak, M. and Godfrey, J. S.: Regional Oceanography: An Introduction, Chapter 12: Hydrology of the Indian Ocean, 199–214, 1994. a
You, Y.: Implications of the deep circulation and ventilation of the Indian
Ocean on the renewal mechanism of North Atlantic Deep Water, J. Geophys. Res.-Oceans, 105, 23895–23926,
https://doi.org/10.1029/2000jc900105, 2000. a
Zweng, M. M., Reagan, J., Antonov, J., Mishonov, A., Boyer, T., Garcia, H.,
Baranova, O., Johnson, D., Seidov, D., and Bidlle, M.: World Ocean Atlas
2013, Volume 2: Salinity, NOAA Atlas NESDIS, 2, 39,
https://doi.org/10.1182/blood-2011-06-357442, 2013. a, b
Short summary
Oxygen-poor regions in the open ocean restrict marine habitats. Global climate simulations show large uncertainties regarding the prediction of these areas. We analyse the representation of the simulated oxygen minimum zones in the Arabian Sea using 10 climate models. We give an overview of the main deficiencies that cause the model–data misfit in oxygen concentrations. This detailed process analysis shall foster future model improvements regarding the oxygen minimum zone in the Arabian Sea.
Oxygen-poor regions in the open ocean restrict marine habitats. Global climate simulations show...
