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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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Extreme air–sea turbulent fluxes during tropical cyclone Barijat observed by a newly designed drifting buoy. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.08.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Effects of Periodic Tidal Elevations on the Air-Sea Momentum and Turbulent Heat Fluxes in the East China Sea. ATMOSPHERE 2022. [DOI: 10.3390/atmos13010090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Using bulk formulas, two-year platform (fastened to the seabed) hourly observations from 2016 to 2017 in the East China Sea (121.6° E, 32.4° N) are used to investigate the role of the tide-induced surface elevation in changing the fixed observational height and modifying the momentum and air-sea turbulent heat fluxes. The semidiurnal tide-dominated elevation anomalies ranging from −3.6 to 3.9 m change the fixed platform observational height. This change causes hourly differences in the wind stress and latent and sensible heat fluxes between estimates with and without considering surface elevation, with values ranging from −1.5 × 10−3 Nm−2, −10.2 Wm−2, and −3.6 Wm−2 to 2.2 × 10−3 Nm−2, 8.4 Wm−2, and 4.6 Wm−2, respectively. More significant differences occur during spring tides. The differences show weak dependence on the temperature, indicating weak seasonal variations. The mean (maximum) difference percentage relative to the mean magnitude is approximately 3.5% (7%), 1.5% (3%), and 1.5% (3%) for the wind stress and latent and sensible heat fluxes, respectively. The boundary layer stability (BLS) can convert from near-neutral conditions to stable and unstable states in response to tide-induced changes in the observational height, with a probability of occurrence of 2%. Wind anomalies play dominant roles in determining the hourly anomalies of the latent heat flux, regardless of the state of the BLS. Extreme cases, including the cold air outbreak in 2016, tropical cyclones Meranti in 2016, and Ampil in 2018, are also examined. This study will facilitate future observation-reanalysis comparisons in the studied coastal region where ocean–atmosphere-land interactive processes are significant.
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Emerging Pattern of Wind Change over the Eurasian Marginal Seas Revealed by Three Decades of Satellite Ocean-Surface Wind Observations. REMOTE SENSING 2021. [DOI: 10.3390/rs13091707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study provides the first full characterization of decadal changes of surface winds over 10 marginal seas along the Eurasian continent using satellite wind observations. During the three decades (1988–2018), surface warming has occurred in all seas at a rate more pronounced in the South European marginal seas (0.4–0.6 °C per decade) than in the monsoon-influenced North Indian and East Asian marginal seas (0.1–0.2 °C per decade). However, surface winds have not strengthened everywhere. On a basin average, winds have increased over the marginal seas in the subtropical/mid-latitudes, with the rate of increase ranging from 11 to 24 cms−1 per decade. These upward trends reflect primarily the accelerated changes in the 1990s and have largely flattened since 2000. Winds have slightly weakened or remained little changed over the marginal seas in the tropical monsoonal region. Winds over the Red Sea and the Persian Gulf underwent an abrupt shift in the late 1990s that resulted in an elevation of local wind speeds. The varying relationships between wind and SST changes suggest that different marginal seas have responded differently to environmental warming and further studies are needed to gain an improved understanding of climate change on a regional scale.
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Chen S, Huang C, Kuo Y, Tseng Y, Gu Y, Earl K, Chen C, Choi Y, Liou K. Impacts of Saharan Mineral Dust on Air-Sea Interaction over North Atlantic Ocean Using a Fully Coupled Regional Model. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2021; 126:e2020JD033586. [PMID: 33816041 PMCID: PMC8008257 DOI: 10.1029/2020jd033586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/05/2020] [Accepted: 01/10/2021] [Indexed: 06/12/2023]
Abstract
This study examines the modifications of air-sea coupling processes by dust-radiation-cloud interactions over the North Atlantic Ocean using a high-resolution coupled atmosphere-wave-ocean-dust (AWOD) regional model. The dust-induced mechanisms that are responsible for changes of sea surface temperature (SST) and latent and sensible heat fluxes (LHF/SHF) are also examined. Two 3-month numerical experiments are conducted, and they differ only in the activation and deactivation of dust-radiation-cloud interactions. Model results show that the dust significantly reduces surface downward radiation fluxes (SDRF) over the ocean with the maximum change of 20-30 W m-2. Over the dust plume region, the dust effect creates a low-pressure anomaly and a cyclonic circulation anomaly, which drives a positive wind stress curl anomaly, thereby reducing sea surface height and mixed layer depth. However, the SST change by dust, ranging from -0.5 to 0.5 K, has a great spatial variation which differs from the dust plume shape. Dust cools SST around the West African coast, except under the maximum dust plume ridge, and extends westward asymmetrically along the northern and southern edges of the dust plume. Dust unexpectedly warms SST over a large area of the western tropical North Atlantic and north of the dust plume. These SST changes are controlled by different mechanisms. Unlike the SST change pattern, the LHF and SHF changes are mostly reduced underneath the dust plume region, though they are different in detail due to different dominant factors, and increased south of the dust plume over the tropic.
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Affiliation(s)
- Shu‐Hua Chen
- Department of Land, Air, and Water ResourcesUniversity of CaliforniaDavisCAUSA
| | - Chu‐Chun Huang
- Department of Land, Air, and Water ResourcesUniversity of CaliforniaDavisCAUSA
| | - Yi‐Chun Kuo
- Institute of OceanographyNational Taiwan UniversityTaipeiTaiwan
| | - Yu‐Heng Tseng
- Institute of OceanographyNational Taiwan UniversityTaipeiTaiwan
| | - Yu Gu
- Joint Institute for Regional Earth System Science and Engineering and Department of Atmospheric and Oceanic SciencesUniversity of CaliforniaLos AngelesCAUSA
- NASA Goddard Space Flight CenterGreenbeltMDUSA
| | - Kenneth Earl
- Department of Land, Air, and Water ResourcesUniversity of CaliforniaDavisCAUSA
| | - Chih‐Ying Chen
- Department of Land, Air, and Water ResourcesUniversity of CaliforniaDavisCAUSA
- Research Center for Environmental ChangesAcademia SinicaTaipeiTaiwan
| | - Yonghan Choi
- Department of Land, Air, and Water ResourcesUniversity of CaliforniaDavisCAUSA
- Korea Polar Research InstituteIncheonSouth Korea
| | - Kuo‐Nan Liou
- Joint Institute for Regional Earth System Science and Engineering and Department of Atmospheric and Oceanic SciencesUniversity of CaliforniaLos AngelesCAUSA
- NASA Goddard Space Flight CenterGreenbeltMDUSA
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Yu L, Josey SA, Bingham FM, Lee T. Intensification of the global water cycle and evidence from ocean salinity: a synthesis review. Ann N Y Acad Sci 2020; 1472:76-94. [PMID: 32386251 DOI: 10.1111/nyas.14354] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/03/2020] [Accepted: 04/08/2020] [Indexed: 11/28/2022]
Abstract
The ocean plays a dominant role in the global water cycle. It is the center of action for global evaporation and precipitation and supplies the moisture that falls as continental precipitation. It also acts to some extent as nature's rain gauge, as it tells us about the long-term changes in the global water cycle through monitoring of the changes in ocean surface salinity. As climate warms, the global water cycle is expected to intensify as a result of the strong nonlinear dependence of water vapor pressure (moisture-holding capacity) on temperature. Such change is of great concern, as it has profound socioeconomic impacts throughout the globe. Despite the evidence of an intensified global water cycle, two important questions remain: What is the pattern of the warming-induced intensification of the water cycle? and What is the rate of intensification? Our article provides a synthesis review of recent progress in diagnosing and understanding the changes in both the global water cycle and ocean salinity in recent decades. Targeted numerical ocean model experiments are also reviewed to provide insights into the response of salinity to the changes in evaporation-minus-precipitation flux, meltwater runoff, and ocean warming.
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Affiliation(s)
- Lisan Yu
- Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
| | - Simon A Josey
- National Oceanography Centre, Southampton, United Kingdom
| | - Frederick M Bingham
- Center for Marine Science, University of North Carolina Wilmington, Wilmington, North Carolina
| | - Tong Lee
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
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Penny SG, Akella S, Balmaseda MA, Browne P, Carton JA, Chevallier M, Counillon F, Domingues C, Frolov S, Heimbach P, Hogan P, Hoteit I, Iovino D, Laloyaux P, Martin MJ, Masina S, Moore AM, de Rosnay P, Schepers D, Sloyan BM, Storto A, Subramanian A, Nam S, Vitart F, Yang C, Fujii Y, Zuo H, O’Kane T, Sandery P, Moore T, Chapman CC. Observational Needs for Improving Ocean and Coupled Reanalysis, S2S Prediction, and Decadal Prediction. FRONTIERS IN MARINE SCIENCE 2019; 6:391. [PMID: 31534949 PMCID: PMC6750049 DOI: 10.3389/fmars.2019.00391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Developments in observing system technologies and ocean data assimilation (DA) are symbiotic. New observation types lead to new DA methods and new DA methods, such as coupled DA, can change the value of existing observations or indicate where new observations can have greater utility for monitoring and prediction. Practitioners of DA are encouraged to make better use of observations that are already available, for example, taking advantage of strongly coupled DA so that ocean observations can be used to improve atmospheric analyses and vice versa. Ocean reanalyses are useful for the analysis of climate as well as the initialization of operational long-range prediction models. There are many remaining challenges for ocean reanalyses due to biases and abrupt changes in the ocean-observing system throughout its history, the presence of biases and drifts in models, and the simplifying assumptions made in DA solution methods. From a governance point of view, more support is needed to bring the ocean-observing and DA communities together. For prediction applications, there is wide agreement that protocols are needed for rapid communication of ocean-observing data on numerical weather prediction (NWP) timescales. There is potential for new observation types to enhance the observing system by supporting prediction on multiple timescales, ranging from the typical timescale of NWP, covering hours to weeks, out to multiple decades. Better communication between DA and observation communities is encouraged in order to allow operational prediction centers the ability to provide guidance for the design of a sustained and adaptive observing network.
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Affiliation(s)
- Stephen G. Penny
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD, United States
| | - Santha Akella
- National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, MD, United States
| | | | - Philip Browne
- European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
| | - James A. Carton
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD, United States
| | | | | | - Catia Domingues
- Antarctic Climate and Ecosystems Cooperative Research Centre, Hobart, TAS, Australia
| | - Sergey Frolov
- Naval Research Laboratory, Monterey, CA, United States
| | | | - Patrick Hogan
- Naval Research Laboratory, Stennis Space Center, MS, United States
| | - Ibrahim Hoteit
- King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | | | - Patrick Laloyaux
- European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
| | | | - Simona Masina
- Euro-Mediterranean Center on Climate Change, Lecce, Italy
| | - Andrew M. Moore
- University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Patricia de Rosnay
- European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
| | - Dinand Schepers
- European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
| | - Bernadette M. Sloyan
- Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
| | - Andrea Storto
- NATO Centre for Maritime Research and Experimentation, La Spezia, Italy
| | - Aneesh Subramanian
- Department of Atmospheric and Oceanic Science, University of Colorado, Boulder, Boulder, CO, United States
| | | | - Frederic Vitart
- European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
| | - Chunxue Yang
- Istituto di Scienze Marine, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Yosuke Fujii
- JMA Meteorological Research Institute, Tsukuba, Japan
| | - Hao Zuo
- European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
| | - Terry O’Kane
- Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
| | - Paul Sandery
- Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
| | - Thomas Moore
- Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
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