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Gray AR. The Four-Dimensional Carbon Cycle of the Southern Ocean. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:163-190. [PMID: 37738480 DOI: 10.1146/annurev-marine-041923-104057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
The Southern Ocean plays a fundamental role in the global carbon cycle, dominating the oceanic uptake of heat and carbon added by anthropogenic activities and modulating atmospheric carbon concentrations in past, present, and future climates. However, the remote and extreme conditions found there make the Southern Ocean perpetually one of the most difficult places on the planet to observe and to model, resulting in significant and persistent uncertainties in our knowledge of the oceanic carbon cycle there. The flow of carbon in the Southern Ocean is traditionally understood using a zonal mean framework, in which the meridional overturning circulation drives the latitudinal variability observed in both air-sea flux and interior ocean carbon concentration. However, recent advances, based largely on expanded observation and modeling capabilities in the region, reveal the importance of processes acting at smaller scales, including basin-scale zonal asymmetries in mixed-layer depth, mesoscale eddies, and high-frequency atmospheric variability. Assessing the current state of knowledge and remaining gaps emphasizes the need to move beyond the zonal mean picture and embrace a four-dimensional understanding of the carbon cycle in the Southern Ocean.
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Affiliation(s)
- Alison R Gray
- School of Oceanography, University of Washington, Seattle, Washington, USA;
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Swart S, du Plessis MD, Nicholson SA, Monteiro PMS, Dove LA, Thomalla S, Thompson AF, Biddle LC, Edholm JM, Giddy I, Heywood KJ, Lee C, Mahadevan A, Shilling G, de Souza RB. The Southern Ocean mixed layer and its boundary fluxes: fine-scale observational progress and future research priorities. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220058. [PMID: 37150200 PMCID: PMC10164470 DOI: 10.1098/rsta.2022.0058] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 03/03/2023] [Indexed: 05/09/2023]
Abstract
Interactions between the upper ocean and air-ice-ocean fluxes in the Southern Ocean play a critical role in global climate by impacting the overturning circulation and oceanic heat and carbon uptake. Remote and challenging conditions have led to sparse observational coverage, while ongoing field programmes often fail to collect sufficient information in the right place or at the time-space scales required to constrain the variability occurring in the coupled ocean-atmosphere system. Only within the last 10 years have we been able to directly observe and assess the role of the fine-scale ocean and rapidly evolving atmospheric marine boundary layer on the upper limb of the Southern Ocean's overturning circulation. This review summarizes advances in mechanistic understanding, arising in part from observational programmes using autonomous platforms, of the fine-scale processes (1-100 km, hours-seasons) influencing the Southern Ocean mixed layer and its variability. We also review progress in observing the ocean interior connections and the coupled interactions between the ocean, atmosphere and cryosphere that moderate air-sea fluxes of heat and carbon. Most examples provided are for the ice-free Southern Ocean, while major challenges remain for observing the ice-covered ocean. We attempt to elucidate contemporary research gaps and ongoing/future efforts needed to address them. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.
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Affiliation(s)
- Sebastiaan Swart
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Oceanography, University of Cape Town, Rondebosch, South Africa
| | | | | | | | - Lilian A. Dove
- Environmental Science and Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Sandy Thomalla
- Southern Ocean Carbon-Climate Observatory, CSIR, Cape Town, South Africa
| | - Andrew F. Thompson
- Environmental Science and Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Louise C. Biddle
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Johan M. Edholm
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Isabelle Giddy
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- Southern Ocean Carbon-Climate Observatory, CSIR, Cape Town, South Africa
| | - Karen J. Heywood
- Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, UK
| | - Craig Lee
- Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | | | - Geoff Shilling
- Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Ronald Buss de Souza
- Earth System Numerical Modeling Division, National Institute for Space Research (INPE), Cachoeira Paulista, Brazil
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Pezzi LP, Quadro MFL, Souza EB, Miller AJ, Rao VB, Rosa EB, Santini MF, Bender A, Souza RB, Cabrera MJ, Parise CK, Carvalho JT, Lima LS, de Quadros MRL, Nehme DM, António JF. Oceanic SACZ produces an abnormally wet 2021/2022 rainy season in South America. Sci Rep 2023; 13:1455. [PMID: 36702914 PMCID: PMC9879931 DOI: 10.1038/s41598-023-28803-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/24/2023] [Indexed: 01/27/2023] Open
Abstract
The oceanic South Atlantic Convergence Zone (SACZ) has played a major role during South America's 2021/2022 summer extreme rainy season, being responsible for more than 90% of the precipitation in some regions of Southeast Brazil and in some regions of the Southwestern Atlantic Ocean (SWA). The summer of 2021/2022 was unique and rare and considered an abnormally humid season as verified by official Brazilian Institutes. First, the unusual number of cases of SACZ episodes (seven), was the highest recorded in the last decade. Second, all the cases that occurred were oceanic SACZ that assumed characteristics of an Atmospheric River and produced an excessively anomalous amount of precipitation during this period. Excess precipitation along with the regions located in mountainous and very uneven relief, which by orographic effects favors high precipitation volumes, were responsible for amplifying the observed impacts, such as landslides and floods that caused several losses to society. We also showed the main effects of coupling and interaction between the waters of the surface layer of the SWA and the atmosphere. Our learning from this study ends with the unprecedented results of how the marine atmospheric boundary layer (MABL) is locally modulated by the sea surface temperature (SST) that lies just below it. Until the present moment, we emphasize that this important mechanism has not been widely highlighted in the literature, showing that even though the ocean is colder than before oceanic SACZ is established, it is still warmer than the overlying air, thus, the ocean continues to be an active source of heat and moisture for the atmosphere and enhances the MABL instability process.
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Affiliation(s)
- Luciano P. Pezzi
- grid.419222.e0000 0001 2116 4512Laboratory of Ocean and Atmosphere Studies (LOA), Earth Observation and Geoinformatics Division (DIOTG), National Institute for Space Research (INPE), São José dos Campos, São Paulo Brazil
| | - Mario F. L. Quadro
- grid.462200.20000 0004 0370 3270Federal Institute of Santa Catarina (IFSC), Florianópolis, Santa Catarina Brazil
| | - Everaldo B. Souza
- grid.271300.70000 0001 2171 5249Federal University of Para (UFPA), Belém, Pará Brazil
| | - Arthur J. Miller
- grid.266100.30000 0001 2107 4242Scripps Institution of Oceanography (SIO), University of California San Diego (UCSD), San Diego, CA USA
| | - Vadlamudi B. Rao
- grid.419222.e0000 0001 2116 4512Laboratory of Ocean and Atmosphere Studies (LOA), Earth Observation and Geoinformatics Division (DIOTG), National Institute for Space Research (INPE), São José dos Campos, São Paulo Brazil
| | - Eliana B. Rosa
- grid.419222.e0000 0001 2116 4512Laboratory of Ocean and Atmosphere Studies (LOA), Earth Observation and Geoinformatics Division (DIOTG), National Institute for Space Research (INPE), São José dos Campos, São Paulo Brazil
| | - Marcelo F. Santini
- grid.419222.e0000 0001 2116 4512Laboratory of Ocean and Atmosphere Studies (LOA), Earth Observation and Geoinformatics Division (DIOTG), National Institute for Space Research (INPE), São José dos Campos, São Paulo Brazil
| | - Andréia Bender
- National Center for Monitoring and Early Warning of Natural Disasters (CEMADEN), São José dos Campos, São Paulo Brazil
| | - Ronald B. Souza
- grid.419222.e0000 0001 2116 4512Earth System Numerical Modeling Division, National Institute of Space Research (INPE), Cachoeira Paulista, São Paulo Brazil
| | - Mylene J. Cabrera
- grid.419222.e0000 0001 2116 4512Laboratory of Ocean and Atmosphere Studies (LOA), Earth Observation and Geoinformatics Division (DIOTG), National Institute for Space Research (INPE), São José dos Campos, São Paulo Brazil
| | - Claudia K. Parise
- grid.411204.20000 0001 2165 7632Laboratory for Climate Studies and Modelling, Department of Oceanography, Federal University of Maranhão (UFMA), São Luiz, Maranhão Brazil
| | - Jonas T. Carvalho
- grid.419222.e0000 0001 2116 4512Laboratory of Ocean and Atmosphere Studies (LOA), Earth Observation and Geoinformatics Division (DIOTG), National Institute for Space Research (INPE), São José dos Campos, São Paulo Brazil ,grid.423878.20000 0004 1761 0884Ocean Predictions and Applications, Centro Euro-Mediterraneo sui Cambiamenti Climatici, via Marco Biagi 5, 73100 Lecce, Italy
| | - Luciana S. Lima
- grid.419222.e0000 0001 2116 4512Laboratory of Ocean and Atmosphere Studies (LOA), Earth Observation and Geoinformatics Division (DIOTG), National Institute for Space Research (INPE), São José dos Campos, São Paulo Brazil
| | - Maria Rita L. de Quadros
- grid.462200.20000 0004 0370 3270Federal Institute of Santa Catarina (IFSC), Florianópolis, Santa Catarina Brazil
| | - Douglas M. Nehme
- grid.8536.80000 0001 2294 473XFederal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Rio de Janeiro Brazil
| | - Jaime F. António
- grid.419222.e0000 0001 2116 4512Laboratory of Ocean and Atmosphere Studies (LOA), Earth Observation and Geoinformatics Division (DIOTG), National Institute for Space Research (INPE), São José dos Campos, São Paulo Brazil
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