Zhang Dongxiao

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Zhang
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Dongxiao
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0000-0001-5788-911X

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  • Article
    Measurements from the RV Ronald H. Brown and related platforms as part of the Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC)
    (Copernicus Publications, 2021-04-29) Quinn, Patricia K. ; Thompson, Elizabeth ; Coffman, Derek J. ; Baidar, Sunil ; Bariteau, Ludovic ; Bates, Timothy S. ; Bigorre, Sebastien P. ; Brewer, Alan ; de Boer, Gijs ; de Szoeke, Simon P. ; Drushka, Kyla ; Foltz, Gregory R. ; Intrieri, Janet ; Iyer, Suneil ; Fairall, Christopher W. ; Gaston, Cassandra J. ; Jansen, Friedhelm ; Johnson, James E. ; Krüger, Ovid O. ; Marchbanks, Richard D. ; Moran, Kenneth P. ; Noone, David ; Pezoa, Sergio ; Pincus, Robert ; Plueddemann, Albert J. ; Pöhlker, Mira L. ; Pöschl, Ulrich ; Quinones Melendez, Estefania ; Royer, Haley M. ; Szczodrak, Malgorzata ; Thomson, Jim ; Upchurch, Lucia M. ; Zhang, Chidong ; Zhang, Dongxiao ; Zuidema, Paquita
    The Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC) took place from 7 January to 11 July 2020 in the tropical North Atlantic between the eastern edge of Barbados and 51∘ W, the longitude of the Northwest Tropical Atlantic Station (NTAS) mooring. Measurements were made to gather information on shallow atmospheric convection, the effects of aerosols and clouds on the ocean surface energy budget, and mesoscale oceanic processes. Multiple platforms were deployed during ATOMIC including the NOAA RV Ronald H. Brown (RHB) (7 January to 13 February) and WP-3D Orion (P-3) aircraft (17 January to 10 February), the University of Colorado's Robust Autonomous Aerial Vehicle-Endurant Nimble (RAAVEN) uncrewed aerial system (UAS) (24 January to 15 February), NOAA- and NASA-sponsored Saildrones (12 January to 11 July), and Surface Velocity Program Salinity (SVPS) surface ocean drifters (23 January to 29 April). The RV Ronald H. Brown conducted in situ and remote sensing measurements of oceanic and atmospheric properties with an emphasis on mesoscale oceanic–atmospheric coupling and aerosol–cloud interactions. In addition, the ship served as a launching pad for Wave Gliders, Surface Wave Instrument Floats with Tracking (SWIFTs), and radiosondes. Details of measurements made from the RV Ronald H. Brown, ship-deployed assets, and other platforms closely coordinated with the ship during ATOMIC are provided here. These platforms include Saildrone 1064 and the RAAVEN UAS as well as the Barbados Cloud Observatory (BCO) and Barbados Atmospheric Chemistry Observatory (BACO). Inter-platform comparisons are presented to assess consistency in the data sets. Data sets from the RV Ronald H. Brown and deployed assets have been quality controlled and are publicly available at NOAA's National Centers for Environmental Information (NCEI) data archive (https://www.ncei.noaa.gov/archive/accession/ATOMIC-2020, last access: 2 April 2021). Point-of-contact information and links to individual data sets with digital object identifiers (DOIs) are provided herein.
  • Article
    Comparing air-sea flux measurements from a new unmanned surface vehicle and proven platforms during the SPURS-2 field campaign.
    (Oceanography Society, 2019-06-14) Zhang, Dongxiao ; Cronin, Meghan F. ; Meinig, Christian ; Farrar, J. Thomas ; Jenkins, Richard ; Peacock, David ; Keene, Jennifer ; Sutton, Adrienne J. ; Yang, Qiong
    Two saildrones participated in the Salinity Processes in the Upper-ocean Regional Study 2 (SPURS-2) field campaign at 10°N, 125°W, as part of their more than six-month Tropical Pacific Observing System (TPOS)-2020 pilot study in the eastern tropical Pacific. The two saildrones were launched from San Francisco, California, on September 1, 2017, and arrived at the SPURS-2 region on October 15, one week before R/V Revelle. Upon arrival at the SPURS-2 site, they each began a two-week repeat pattern, sailing around the program’s central moored surface buoy. The heavily instrumented Woods Hole Oceanographic Institution (WHOI) SPURS-2 buoy serves as a benchmark for validating the saildrone measurements for air-sea fluxes. The data collected by the WHOI buoy and the saildrones were found to be in reasonably good agreement. Although of short duration, these ship-saildrone-buoy comparisons are encouraging as they provide enhanced understanding of measurements by various platforms in a rapidly changing subsynoptic weather system. The saildrones were generally able to navigate the challenging Intertropical Convergence Zone, where winds are low and currents can be strong, demonstrating that the saildrone is an effective platform for observing a wide range of oceanographic variables important to air-sea interaction studies.
  • Article
    The barrier layer effect on the heat and freshwater balance from moored observations in the eastern Pacific fresh pool
    (American Meteorological Society, 2022-07-27) Katsura, Shota ; Sprintall, Janet ; Farrar, J. Thomas ; Zhang, Dongxiao ; Cronin, Meghan F.
    Formation and evolution of barrier layers (BLs) and associated temperature inversions (TIs) were investigated using a 1-yr time series of oceanic and air–sea surface observations from three moorings deployed in the eastern Pacific fresh pool. BL thickness and TI amplitude showed a seasonality with maxima in boreal summer and autumn when BLs were persistently present. Mixed layer salinity (MLS) and mixed layer temperature (MLT) budgets were constructed to investigate the formation mechanism of BLs and TIs. The MLS budget showed that BLs were initially formed in response to horizontal advection of freshwater in boreal summer and then primarily maintained by precipitation. The MLT budget revealed that penetration of shortwave radiation through the mixed layer base is the dominant contributor to TI formation through subsurface warming. Geostrophic advection is a secondary contributor to TI formation through surface cooling. When the BL exists, the cooling effect from entrainment and the warming effect from detrainment are both significantly reduced. In addition, when the BL is associated with the presence of a TI, entrainment works to warm the mixed layer. The presence of BLs makes the shallower mixed layer more sensitive to surface heat and freshwater fluxes, acting to enhance the formation of TIs that increase the subsurface warming via shortwave penetration.
  • Article
    Super sites for advancing understanding of the oceanic and atmospheric boundary layers
    (Marine Technology Society, 2021-05-01) Clayson, Carol A. ; Centurioni, Luca R. ; Cronin, Meghan F. ; Edson, James B. ; Gille, Sarah T. ; Muller-Karger, Frank E. ; Parfitt, Rhys ; Riihimaki, Laura D. ; Smith, Shawn R. ; Swart, Sebastiaan ; Vandemark, Douglas ; Villas Bôas, Ana B. ; Zappa, Christopher J. ; Zhang, Dongxiao
    Air‐sea interactions are critical to large-scale weather and climate predictions because of the ocean's ability to absorb excess atmospheric heat and carbon and regulate exchanges of momentum, water vapor, and other greenhouse gases. These exchanges are controlled by molecular, turbulent, and wave-driven processes in the atmospheric and oceanic boundary layers. Improved understanding and representation of these processes in models are key for increasing Earth system prediction skill, particularly for subseasonal to decadal time scales. Our understanding and ability to model these processes within this coupled system is presently inadequate due in large part to a lack of data: contemporaneous long-term observations from the top of the marine atmospheric boundary layer (MABL) to the base of the oceanic mixing layer. We propose the concept of “Super Sites” to provide multi-year suites of measurements at specific locations to simultaneously characterize physical and biogeochemical processes within the coupled boundary layers at high spatial and temporal resolution. Measurements will be made from floating platforms, buoys, towers, and autonomous vehicles, utilizing both in-situ and remote sensors. The engineering challenges and level of coordination, integration, and interoperability required to develop these coupled ocean‐atmosphere Super Sites place them in an “Ocean Shot” class.
  • Article
    Air-sea fluxes with a focus on heat and momentum
    (Frontiers Media, 2019-07-31) Cronin, Meghan F. ; Gentemann, Chelle L. ; Edson, James B. ; Ueki, Iwao ; Bourassa, Mark A. ; Brown, Shannon ; Clayson, Carol A. ; Fairall, Christopher W. ; Farrar, J. Thomas ; Gille, Sarah T. ; Gulev, Sergey ; Josey, Simon A. ; Kato, Seiji ; Katsumata, Masaki ; Kent, Elizabeth ; Krug, Marjolaine ; Minnett, Peter J. ; Parfitt, Rhys ; Pinker, Rachel T. ; Stackhouse, Paul W., Jr. ; Swart, Sebastiaan ; Tomita, Hiroyuki ; Vandemark, Douglas ; Weller, Robert A. ; Yoneyama, Kunio ; Yu, Lisan ; Zhang, Dongxiao
    Turbulent and radiative exchanges of heat between the ocean and atmosphere (hereafter heat fluxes), ocean surface wind stress, and state variables used to estimate them, are Essential Ocean Variables (EOVs) and Essential Climate Variables (ECVs) influencing weather and climate. This paper describes an observational strategy for producing 3-hourly, 25-km (and an aspirational goal of hourly at 10-km) heat flux and wind stress fields over the global, ice-free ocean with breakthrough 1-day random uncertainty of 15 W m–2 and a bias of less than 5 W m–2. At present this accuracy target is met only for OceanSITES reference station moorings and research vessels (RVs) that follow best practices. To meet these targets globally, in the next decade, satellite-based observations must be optimized for boundary layer measurements of air temperature, humidity, sea surface temperature, and ocean wind stress. In order to tune and validate these satellite measurements, a complementary global in situ flux array, built around an expanded OceanSITES network of time series reference station moorings, is also needed. The array would include 500–1000 measurement platforms, including autonomous surface vehicles, moored and drifting buoys, RVs, the existing OceanSITES network of 22 flux sites, and new OceanSITES expanded in 19 key regions. This array would be globally distributed, with 1–3 measurement platforms in each nominal 10° by 10° box. These improved moisture and temperature profiles and surface data, if assimilated into Numerical Weather Prediction (NWP) models, would lead to better representation of cloud formation processes, improving state variables and surface radiative and turbulent fluxes from these models. The in situ flux array provides globally distributed measurements and metrics for satellite algorithm development, product validation, and for improving satellite-based, NWP and blended flux products. In addition, some of these flux platforms will also measure direct turbulent fluxes, which can be used to improve algorithms for computation of air-sea exchange of heat and momentum in flux products and models. With these improved air-sea fluxes, the ocean’s influence on the atmosphere will be better quantified and lead to improved long-term weather forecasts, seasonal-interannual-decadal climate predictions, and regional climate projections.
  • Article
    Global in situ observations of essential climate and ocean variables at the air-sea interface
    (Frontiers Media, 2019-07-25) Centurioni, Luca R. ; Turton, Jon ; Lumpkin, Rick ; Braasch, Lancelot ; Brassington, Gary ; Chao, Yi ; Charpentier, Etienne ; Chen, Zhaohui ; Corlett, Gary ; Dohan, Kathleen ; Donlon, Craig ; Gallage, Champika ; Hormann, Verena ; Ignatov, Alexander ; Ingleby, Bruce ; Jensen, Robert ; Kelly-Gerreyn, Boris A. ; Koszalka, Inga M. ; Lin, Xiaopei ; Lindstrom, Eric ; Maximenko, Nikolai ; Merchant, Christopher J. ; Minnett, Peter J. ; O’Carroll, Anne ; Paluszkiewicz, Theresa ; Poli, Paul ; Poulain, Pierre Marie ; Reverdin, Gilles ; Sun, Xiujun ; Swail, Val ; Thurston, Sidney ; Wu, Lixin ; Yu, Lisan ; Wang, Bin ; Zhang, Dongxiao
    The air–sea interface is a key gateway in the Earth system. It is where the atmosphere sets the ocean in motion, climate/weather-relevant air–sea processes occur, and pollutants (i.e., plastic, anthropogenic carbon dioxide, radioactive/chemical waste) enter the sea. Hence, accurate estimates and forecasts of physical and biogeochemical processes at this interface are critical for sustainable blue economy planning, growth, and disaster mitigation. Such estimates and forecasts rely on accurate and integrated in situ and satellite surface observations. High-impact uses of ocean surface observations of essential ocean/climate variables (EOVs/ECVs) include (1) assimilation into/validation of weather, ocean, and climate forecast models to improve their skill, impact, and value; (2) ocean physics studies (i.e., heat, momentum, freshwater, and biogeochemical air–sea fluxes) to further our understanding and parameterization of air–sea processes; and (3) calibration and validation of satellite ocean products (i.e., currents, temperature, salinity, sea level, ocean color, wind, and waves). We review strengths and limitations, impacts, and sustainability of in situ ocean surface observations of several ECVs and EOVs. We draw a 10-year vision of the global ocean surface observing network for improved synergy and integration with other observing systems (e.g., satellites), for modeling/forecast efforts, and for a better ocean observing governance. The context is both the applications listed above and the guidelines of frameworks such as the Global Ocean Observing System (GOOS) and Global Climate Observing System (GCOS) (both co-sponsored by the Intergovernmental Oceanographic Commission of UNESCO, IOC–UNESCO; the World Meteorological Organization, WMO; the United Nations Environment Programme, UNEP; and the International Science Council, ISC). Networks of multiparametric platforms, such as the global drifter array, offer opportunities for new and improved in situ observations. Advances in sensor technology (e.g., low-cost wave sensors), high-throughput communications, evolving cyberinfrastructures, and data information systems with potential to improve the scope, efficiency, integration, and sustainability of the ocean surface observing system are explored.
  • Article
    EUREC4A
    (Copernicus Publications, 2021-08-25) Stevens, Bjorn ; Bony, Sandrine ; Farrell, David ; Ament, Felix ; Blyth, Alan ; Fairall, Christopher W. ; Karstensen, Johannes ; Quinn, Patricia K. ; Speich, Sabrina ; Acquistapace, Claudia ; Aemisegger, Franziska ; Albright, Anna Lea ; Bellenger, Hugo ; Bodenschatz, Eberhard ; Caesar, Kathy-Ann ; Chewitt-Lucas, Rebecca ; de Boer, Gijs ; Delanoë, Julien ; Denby, Leif ; Ewald, Florian ; Fildier, Benjamin ; Forde, Marvin ; George, Geet ; Gross, Silke ; Hagen, Martin ; Hausold, Andrea ; Heywood, Karen J. ; Hirsch, Lutz ; Jacob, Marek ; Jansen, Friedhelm ; Kinne, Stefan ; Klocke, Daniel ; Kölling, Tobias ; Konow, Heike ; Lothon, Marie ; Mohr, Wiebke ; Naumann, Ann Kristin ; Nuijens, Louise ; Olivier, Léa ; Pincus, Robert ; Pöhlker, Mira L. ; Reverdin, Gilles ; Roberts, Gregory ; Schnitt, Sabrina ; Schulz, Hauke ; Siebesma, Pier ; Stephan, Claudia Christine ; Sullivan, Peter P. ; Touzé-Peiffer, Ludovic ; Vial, Jessica ; Vogel, Raphaela ; Zuidema, Paquita ; Alexander, Nicola ; Alves, Lyndon ; Arixi, Sophian ; Asmath, Hamish ; Bagheri, Gholamhossein ; Baier, Katharina ; Bailey, Adriana ; Baranowski, Dariusz ; Baron, Alexandre ; Barrau, Sébastien ; Barrett, Paul A. ; Batier, Frédéric ; Behrendt, Andreas ; Bendinger, Arne ; Beucher, Florent ; Bigorre, Sebastien P. ; Blades, Edmund ; Blossey, Peter ; Bock, Olivier ; Böing, Steven ; Bosser, Pierre ; Bourras, Denis ; Bouruet-Aubertot, Pascale ; Bower, Keith ; Branellec, Pierre ; Branger, Hubert ; Brennek, Michal ; Brewer, Alan ; Brilouet, Pierre-Etienne ; Brügmann, Björn ; Buehler, Stefan A. ; Burke, Elmo ; Burton, Ralph ; Calmer, Radiance ; Canonici, Jean-Christophe ; Carton, Xavier ; Cato, Gregory, Jr. ; Charles, Jude Andre ; Chazette, Patrick ; Chen, Yanxu ; Chilinski, Michal T. ; Choularton, Thomas ; Chuang, Patrick ; Clarke, Shamal ; Coe, Hugh ; Cornet, Céline ; Coutris, Pierre ; Couvreux, Fleur ; Crewell, Susanne ; Cronin, Timothy W. ; Cui, Zhiqiang ; Cuypers, Yannis ; Daley, Alton ; Damerell, Gillian M. ; Dauhut, Thibaut ; Deneke, Hartwig ; Desbios, Jean-Philippe ; Dörner, Steffen ; Donner, Sebastian ; Douet, Vincent ; Drushka, Kyla ; Dütsch, Marina ; Ehrlich, André ; Emanuel, Kerry A. ; Emmanouilidis, Alexandros ; Etienne, Jean-Claude ; Etienne-Leblanc, Sheryl ; Faure, Ghislain ; Feingold, Graham ; Ferrero, Luca ; Fix, Andreas ; Flamant, Cyrille ; Flatau, Piotr Jacek ; Foltz, Gregory R. ; Forster, Linda ; Furtuna, Iulian ; Gadian, Alan ; Galewsky, Joseph ; Gallagher, Martin ; Gallimore, Peter ; Gaston, Cassandra J. ; Gentemann, Chelle L. ; Geyskens, Nicolas ; Giez, Andreas ; Gollop, John ; Gouirand, Isabelle ; Gourbeyre, Christophe ; de Graaf, Dörte ; de Graaf, Geiske E. ; Grosz, Robert ; Güttler, Johannes ; Gutleben, Manuel ; Hall, Kashawn ; Harris, George ; Helfer, Kevin C. ; Henze, Dean ; Herbert, Calvert ; Holanda, Bruna ; Ibanez-Landeta, Antonio ; Intrieri, Janet ; Iyer, Suneil ; Julien, Fabrice ; Kalesse, Heike ; Kazil, Jan ; Kellman, Alexander ; Kidane, Abiel T. ; Kirchner, Ulrike ; Klingebiel, Marcus ; Körner, Mareike ; Kremper, Leslie Ann ; Kretzschmar, Jan ; Krüger, Ovid O. ; Kumala, Wojciech ; Kurz, Armin ; L'Hégareta, Pierre ; Labaste, Matthieu ; Lachlan-Cope, Thomas ; Laing, Arlene ; Landschützer, Peter ; Lang, Theresa ; Lange, Diego ; Lange, Ingo ; Laplace, Clément ; Lavik, Gauke ; Laxenaire, Rémi ; Le Bihan, Caroline ; Leandro, Mason ; Lefevre, Nathalie ; Lena, Marius ; Lenschow, Donald ; Li, Qiang ; Lloyd, Gary ; Los, Sebastian ; Losi, Niccolò ; Lovell, Oscar ; Luneau, Christopher ; Makuch, Przemyslaw ; Malinowski, Szymon ; Manta, Gaston ; Marinou, Eleni ; Marsden, Nicholas ; Masson, Sebastien ; Maury, Nicolas ; Mayer, Bernhard ; Mayers-Als, Margarette ; Mazel, Christophe ; McGeary, Wayne ; McWilliams, James C. ; Mech, Mario ; Mehlmann, Melina ; Meroni, Agostino Niyonkuru ; Mieslinger, Theresa ; Minikin, Andreas ; Minnett, Peter J. ; Möller, Gregor ; Morfa Avalos, Yanmichel ; Muller, Caroline ; Musat, Ionela ; Napoli, Anna ; Neuberger, Almuth ; Noisel, Christophe ; Noone, David ; Nordsiek, Freja ; Nowak, Jakub L. ; Oswald, Lothar ; Parker, Douglas J. ; Peck, Carolyn ; Person, Renaud ; Philippi, Miriam ; Plueddemann, Albert J. ; Pöhlker, Christopher ; Pörtge, Veronika ; Pöschl, Ulrich ; Pologne, Lawrence ; Posyniak, Michał ; Prange, Marc ; Quinones Melendez, Estefania ; Radtke, Jule ; Ramage, Karim ; Reimann, Jens ; Renault, Lionel ; Reus, Klaus ; Reyes, Ashford ; Ribbe, Joachim ; Ringel, Maximilian ; Ritschel, Markus ; Rocha, Cesar B. ; Rochetin, Nicolas ; Röttenbacher, Johannes ; Rollo, Callum ; Royer, Haley M. ; Sadoulet, Pauline ; Saffin, Leo ; Sandiford, Sanola ; Sandu, Irina ; Schäfer, Michael ; Schemann, Vera ; Schirmacher, Imke ; Schlenczek, Oliver ; Schmidt, Jerome M. ; Schröder, Marcel ; Schwarzenboeck, Alfons ; Sealy, Andrea ; Senff, Christoph J. ; Serikov, Ilya ; Shohan, Samkeyat ; Siddle, Elizabeth ; Smirnov, Alexander ; Späth, Florian ; Spooner, Branden ; Stolla, M. Katharina ; Szkółka, Wojciech ; de Szoeke, Simon P. ; Tarot, Stéphane ; Tetoni, Eleni ; Thompson, Elizabeth ; Thomson, Jim ; Tomassini, Lorenzo ; Totems, Julien ; Ubele, Alma Anna ; Villiger, Leonie ; von Arx, Jan ; Wagner, Thomas ; Walther, Andi ; Webber, Ben ; Wendisch, Manfred ; Whitehall, Shanice ; Wiltshire, Anton ; Wing, Allison A. ; Wirth, Martin ; Wiskandt, Jonathan ; Wolf, Kevin ; Worbes, Ludwig ; Wright, Ethan ; Young, Shanea ; Zhang, Chidong ; Zhang, Dongxiao ; Ziemen, Florian ; Zinner, Tobias ; Zöger, Martin
    The science guiding the EUREC4A campaign and its measurements is presented. EUREC4A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EUREC4A marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200 km) and larger (500 km) scales, roughly 400 h of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10 000 profiles), lower atmosphere (continuous profiling), and along the air–sea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EUREC4A explored – from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation – are presented along with an overview of EUREC4A's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at https://doi.org/10.25326/165 (Stevens, 2021), and a film documenting the campaign is provided as a video supplement.
  • Article
    Global perspectives on observing ocean boundary current systems
    (Frontiers Media, 2019-08-08) Todd, Robert E. ; Chavez, Francisco P. ; Clayton, Sophie A. ; Cravatte, Sophie ; Goes, Marlos Pereira ; Graco, Michelle ; Lin, Xiaopei ; Sprintall, Janet ; Zilberman, Nathalie ; Archer, Matthew ; Arístegui, Javier ; Balmaseda, Magdalena A. ; Bane, John M. ; Baringer, Molly O. ; Barth, John A. ; Beal, Lisa M. ; Brandt, Peter ; Calil, Paulo H. R. ; Campos, Edmo ; Centurioni, Luca R. ; Chidichimo, Maria Paz ; Cirano, Mauro ; Cronin, Meghan F. ; Curchitser, Enrique N. ; Davis, Russ E. ; Dengler, Marcus ; deYoung, Brad ; Dong, Shenfu ; Escribano, Ruben ; Fassbender, Andrea ; Fawcett, Sarah E. ; Feng, Ming ; Goni, Gustavo J. ; Gray, Alison R. ; Gutiérrez, Dimitri ; Hebert, Dave ; Hummels, Rebecca ; Ito, Shin-ichi ; Krug, Marjolaine ; Lacan, Francois ; Laurindo, Lucas ; Lazar, Alban ; Lee, Craig M. ; Lengaigne, Matthieu ; Levine, Naomi M. ; Middleton, John ; Montes, Ivonne ; Muglia, Michael ; Nagai, Takeyoshi ; Palevsky, Hilary I. ; Palter, Jaime B. ; Phillips, Helen E. ; Piola, Alberto R. ; Plueddemann, Albert J. ; Qiu, Bo ; Rodrigues, Regina ; Roughan, Moninya ; Rudnick, Daniel L. ; Rykaczewski, Ryan R. ; Saraceno, Martin ; Seim, Harvey E. ; Sen Gupta, Alexander ; Shannon, Lynne ; Sloyan, Bernadette M. ; Sutton, Adrienne J. ; Thompson, LuAnne ; van der Plas, Anja K. ; Volkov, Denis L. ; Wilkin, John L. ; Zhang, Dongxiao ; Zhang, Linlin
    Ocean boundary current systems are key components of the climate system, are home to highly productive ecosystems, and have numerous societal impacts. Establishment of a global network of boundary current observing systems is a critical part of ongoing development of the Global Ocean Observing System. The characteristics of boundary current systems are reviewed, focusing on scientific and societal motivations for sustained observing. Techniques currently used to observe boundary current systems are reviewed, followed by a census of the current state of boundary current observing systems globally. The next steps in the development of boundary current observing systems are considered, leading to several specific recommendations.
  • Article
    Saildrone direct covariance wind stress in various wind and current regimes of the tropical Pacific
    (American Meteorological Society, 2023-04-01) Reeves Eyre, J. E. Jack ; Cronin, Meghan F. ; Zhang, Dongxiao ; Thompson, Elizabeth J. ; Fairall, Christopher W. ; Edson, James B.
    High-frequency wind measurements from Saildrone autonomous surface vehicles are used to calculate wind stress in the tropical east Pacific. Comparison between direct covariance (DC) and bulk wind stress estimates demonstrates very good agreement. Building on previous work that showed the bulk input data were reliable, our results lend credibility to the DC estimates. Wind flow distortion by Saildrones is comparable to or smaller than other platforms. Motion correction results in realistic wind spectra, albeit with signatures of swell-coherent wind fluctuations that may be unrealistically strong. Fractional differences between DC and bulk wind stress magnitude are largest at wind speeds below 4 m s −1 . The size of this effect, however, depends on choice of stress direction assumptions. Past work has shown the importance of using current-relative (instead of Earth-relative) winds to achieve accurate wind stress magnitude. We show that it is also important for wind stress direction. Significance Statement We use data from Saildrone uncrewed oceanographic research vehicles to investigate the horizontal forces applied to the surface of the ocean by the action of the wind. We compare two methods to calculate the forces: one uses several simplifying assumptions, and the other makes fewer assumptions but is error prone if the data are incorrectly processed. The two methods agree well, suggesting that Saildrone vehicles are suitable for both methods and that the data processing methods work. Our results show that it is important to consider ocean currents, as well as winds, in order to achieve accurate magnitude and direction of the surface forces.