ALBERT

Description: The first in situ measurements of seawater density that referred to a geographical position at sea and time of the year were carried out by Count Luigi Ferdinando Marsili between 1679 and 1680 in the Adriatic Sea, Aegean Sea, Marmara Sea, and the Bosporus. Not only was this the first investigation with documented oceanographic measurements carried out at stations, but themeasurements were described in such an accurateway that the authorswere able to reconstruct the observations in modern units. These first measurements concern the ‘‘specific gravity’’ of seawaters (i.e., the ratio between fluid densities). The data reported in the historical oceanographic treatise Osservazioni intorno al Bosforo Tracio (Marsili) allowed the reconstruction of the seawater density at different geographic locations between 1679 and 1680. Marsili’s experimental methodology included the collection of surface and deep water samples, the analysis of the samples with a hydrostatic ampoule, and the use of a reference water to standardize the measurements.Acomparison of reconstructed densities with present-day values shows an agreement within 10%–20% uncertainty, owing to various aspects of the measurement methodology that are difficult to reconstruct from the documentary evidence. Marsili also measured the current speed and the depth of the current inversion in the Bosporus, which are consistent with the present-day knowledge. The experimental data collected in the Bosporus enabledMarsili to enunciate a theory on the cause of the two-layer flow at the strait, demonstrated by his laboratory experiment and later confirmed by many analytical and numerical studies.

Description: American Meteorological Society.

Description: Published

Description: 845 - 860

Description: 4A. Oceanografia e clima

Description: JCR Journal

Description: Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 35 (2018): 893-910, doi:10.1175/JTECH-D-17-0102.1.

Description: Rotary sidescan sonars are widely used to image the seabed given their high temporal and spatial resolution. This high resolution is necessary to resolve bedform dynamics and evolution; however, sidescan sonars do not directly measure bathymetry, limiting their utility. When sidescan sonars are mounted close to the seabed, bedforms may create acoustical “shadows” that render previous methods that invert the backscatter intensity to estimate bathymetry and are based on the assumption of a fully insonified seabed ineffective. This is especially true in coastal regions, where bedforms are common features whose large height relative to the water depth may significantly influence the surrounding flow. A method is described that utilizes sonar shadows to estimate bedform height and asymmetry. The method accounts for the periodic structure of bedform fields and the projection of the shadows onto adjacent bedforms. It is validated with bathymetric observations of wave-orbital ripples, with wavelengths ranging from 0.3 to 0.8 m, and tidally reversing megaripples, with wavelengths from 5 to 8 m. In both cases, bathymetric-measuring sonars were deployed in addition to a rotary sidescan sonar to provide a ground truth; however, the bathymetric sonars typically measure different and smaller areas than the rotary sidescan sonar. The shadow-based method and bathymetric-measuring sonar data produce estimates of bedform height that agree by 34.0% ± 27.2% for wave-orbital ripples and 16.6% ± 14.7% for megaripples. Errors for estimates of asymmetry are 1.9% ± 2.1% for wave-orbital ripples and 11.2% ± 9.6% for megaripples.

Description: This project is partially supported by the National Science Foundation through a Graduate Research Fellowship and a Massachusetts Institute of Technology Energy Initiative Fellowship. Additionally, funding used in developing the method was obtained from NSF Grants OCE-1634481 and OCE-1635151. Field work was funded under ONR Grants N00014-06-10329 and N00014-13-1-0364.

Description: Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 435-453, doi:10.1175/JPO-D-17-0122.1.

Description: Observations of surface waves, currents, and turbulence at the Columbia River mouth are used to investigate the source and vertical structure of turbulence in the surface boundary layer. Turbulent velocity data collected on board freely drifting Surface Wave Instrument Float with Tracking (SWIFT) buoys are corrected for platform motions to estimate turbulent kinetic energy (TKE) and TKE dissipation rates. Both of these quantities are correlated with wave steepness, which has previously been shown to determine wave breaking within the same dataset. Estimates of the turbulent length scale increase linearly with distance from the free surface, and roughness lengths estimated from velocity statistics scale with significant wave height. The vertical decay of turbulence is consistent with a balance between vertical diffusion and dissipation. Below a critical depth, a power-law scaling commonly applied in the literature works well to fit the data. Above this depth, an exponential scaling fits the data well. These results, which are in a surface-following reference frame, are reconciled with results from the literature in a fixed reference frame. A mapping between free-surface and mean-surface reference coordinates suggests 30% of the TKE is dissipated above the mean sea surface.

Description: Funding for this project was provided by the Office of Naval Research as part of the RIVET-II DRI, and for the DARLA group.

Description: Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 607-623, doi:10.1175/JPO-D-17-0189.1.

Description: The roles of straining and dissipation in controlling stratification are derived analytically using a vertical salinity variance method. Stratification is produced by converting horizontal variance to vertical variance via straining, that is, differential advection of horizontal salinity gradients, and stratification is destroyed by the dissipation of vertical variance through turbulent mixing. A numerical model is applied to the Changjiang estuary in order to demonstrate the salinity variance balance and how it reveals the factors controlling stratification. The variance analysis reveals that dissipation reaches its maximum during spring tide in the Changjiang estuary, leading to the lowest stratification. Stratification increases from spring tide to neap tide because of the increasing excess of straining over dissipation. Throughout the spring–neap tidal cycle, straining is almost always larger than dissipation, indicating a net excess of production of vertical variance relative to dissipation. This excess is balanced on average by advection, which exports vertical variance out of the estuarine region into the plume. During neap tide, tidal straining shows a general tendency of destratification during the flood tide and restratification during ebb, consistent with the one-dimensional theory of tidal straining. During spring tide, however, positive straining occurs during flood because of the strong baroclinicity induced by the intensified horizontal salinity gradient. These results indicate that the salinity variance method provides a valuable approach for examining the spatial and temporal variability of stratification in estuaries and coastal environments.

Description: X. Li was supported by the China Scholarship Council. W. R. Geyer was supported by NSF Grants OCE 1736539 and OCE 1634480. J. Zhu was supported by the National Natural Science Foundation of China (41476077 and 41676083). H. Wu was supported by the National Natural Science Foundation of China (41576088 and 41776101).

Description: 2018-09-08

Description: Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 31 (2018): 4847-4863, doi:10.1175/JCLI-D-17-0802.1.

Description: The sensitivity of sea ice to the temperature of inflowing Atlantic water across the Greenland–Scotland Ridge is investigated using an eddy-resolving configuration of the Massachusetts Institute of Technology General Circulation Model with idealized topography. During the last glacial period, when climate on Greenland is known to have been extremely unstable, sea ice is thought to have covered the Nordic seas. The dramatic excursions in climate during this period, seen as large abrupt warming events on Greenland and known as Dansgaard–Oeschger (DO) events, are proposed to have been caused by a rapid retreat of Nordic seas sea ice. Here, we show that a full sea ice cover and Arctic-like stratification can exist in the Nordic seas given a sufficiently cold Atlantic inflow and corresponding low transport of heat across the Greenland–Scotland Ridge. Once sea ice is established, continued sea ice formation and melt efficiently freshens the surface ocean and makes the deeper layers more saline. This creates a strong salinity stratification in the Nordic seas, similar to today’s Arctic Ocean, with a cold fresh surface layer protecting the overlying sea ice from the warm Atlantic water below. There is a nonlinear response in Nordic seas sea ice to Atlantic water temperature with simulated large abrupt changes in sea ice given small changes in inflowing temperature. This suggests that the DO events were more likely to have occurred during periods of reduced warm Atlantic water inflow to the Nordic seas.

Description: The research was supported by the Centre for Climate Dynamics at the Bjerknes Centre for Climate Research. The research leading to these results is part of the ice2ice project funded by the European Research Council under the European Community Seventh Framework Programme (FP7/2007-2013)/ERC Grant Agreement 610055.

Description: Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 29 (2015): 1165–1178, doi:10.1002/2015GB005106.

Description: Current global inventories of ammonia emissions identify the ocean as the largest natural source. This source depends on seawater pH, temperature, and the concentration of total seawater ammonia (NHx(sw)), which reflects a balance between remineralization of organic matter, uptake by plankton, and nitrification. Here we compare [NHx(sw)] from two global ocean biogeochemical models (BEC and COBALT) against extensive ocean observations. Simulated [NHx(sw)] are generally biased high. Improved simulation can be achieved in COBALT by increasing the plankton affinity for NHx within observed ranges. The resulting global ocean emissions is 2.5 TgN a−1, much lower than current literature values (7–23 TgN a−1), including the widely used Global Emissions InitiAtive (GEIA) inventory (8 TgN a−1). Such a weak ocean source implies that continental sources contribute more than half of atmospheric NHx over most of the ocean in the Northern Hemisphere. Ammonia emitted from oceanic sources is insufficient to neutralize sulfate aerosol acidity, consistent with observations. There is evidence over the Equatorial Pacific for a missing source of atmospheric ammonia that could be due to photolysis of marine organic nitrogen at the ocean surface or in the atmosphere. Accommodating this possible missing source yields a global ocean emission of ammonia in the range 2–5 TgN a−1, comparable in magnitude to other natural sources from open fires and soils.

Description: NSF Grant Numbers: AGS-1020594, EF-0424599; WHOI Grant Number: AGS-0328342; UVA; UK SOLAS Knowledge Transfer; SOLAS Project Integration Grant Number: NE/E001696/1

Description: 2016-02-13

Description: Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 45 (2018): 4171-4179, doi:10.1029/2017GL076498.

Description: Estimated rates and efficiency of ocean carbon export flux are sensitive to differences in the depth horizons used to define export, which often vary across methodological approaches. We evaluate sinking particulate organic carbon (POC) flux rates and efficiency (e‐ratios) in a global earth system model, using a range of commonly used depth horizons: the seasonal mixed layer depth, the particle compensation depth, the base of the euphotic zone, a fixed depth horizon of 100 m, and the maximum annual mixed layer depth. Within this single dynamically consistent model framework, global POC flux rates vary by 30% and global e‐ratios by 21% across different depth horizon choices. Zonal variability in POC flux and e‐ratio also depends on the export depth horizon due to pronounced influence of deep winter mixing in subpolar regions. Efforts to reconcile conflicting estimates of export need to account for these systematic discrepancies created by differing depth horizon choices.

Description: Woods Hole Oceanographic Institution (WHOI); National Science Foundation Grant Number: OCE‐1434000

Description: 2018-10-23

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2017

Description: This thesis investigates the formation and subsequent motion of oceanic lithospheric plates through geophysical and petrological methods. Ocean crust and lithosphere forms at mid-ocean ridges as the underlying asthenosphere rises, melts, and flows away from the ridge axis. In Chapters 2 and 3, I present the results from partial melting experiments of mantle peridotite that were conducted in order to examine the mantle melting point, or solidus, beneath a mid-ocean ridge. Chapter 2 determines the peridotite solidus at a single pressure of 1.5 GPa and concludes that the oceanic mantle potential temperature must be ~60ºC hotter than current estimates. Chapter 3 goes further to provide a more accurate parameterization of the anhydrous mantle solidus from experiments over a range of pressures. This chapter concludes that the range of potential temperatures of the mantle beneath mid-ocean ridges and plumes is smaller than currently estimated. Once formed, the oceanic plate moves atop the underlying asthenosphere away from the ridge axis. Chapter 4 uses seafloor magnetotelluric data to investigate the mechanism responsible for plate motion at the lithosphere-asthenosphere boundary. The resulting two dimensional conductivity model shows a simple layered structure. By applying petrological constraints, I conclude that the upper asthenosphere does not contain substantial melt, which suggests that either a thermal or hydration mechanism supports plate motion. Oceanic plate motion has dramatically changed the surface of the Earth over time, and evidence for ancient plate motion is obvious from detailed studies of the longer lived continental lithosphere. In Chapter 5, I investigate past plate motion by inverting magnetotelluric data collected over eastern Zambia. The conductivity model probes the Zambian lithosphere and reveals an ancient subduction zone previously suspected from surface studies. This chapter elucidates the complex lithospheric structure of eastern Zambia and the geometry of the tectonic elements in the region, which collided as a result of past oceanic plate motion. Combined, the chapters of this thesis provide critical constraints on ocean plate dynamics.

Description: Funding for this research was provided by the National Science Foundation Division of Earth Sciences (EAR) grant number 1010432, Division of Ocean Sciences (OCE) grant numbers 1459649 and 0928663, WHOI Deep Ocean Exploration Institute, and the WHOI Academic Programs Office.

Description: Author Posting. © American Meteorological Society, 2017. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 47 (2017): 1061-1075, doi:10.1175/JPO-D-16-0248.1.

Description: A major challenge in modeling the circulation over coral reefs is uncertainty in the drag coefficient because existing estimates span two orders of magnitude. Current and pressure measurements from five coral reefs are used to estimate drag coefficients based on depth-average flow, assuming a balance between the cross-reef pressure gradient and the bottom stress. At two sites wind stress is a significant term in the cross-reef momentum balance and is included in estimating the drag coefficient. For the five coral reef sites and a previous laboratory study, estimated drag coefficients increase as the water depth decreases consistent with open channel flow theory. For example, for a typical coral reef hydrodynamic roughness of 5 cm, observational estimates, and the theory indicate that the drag coefficient decreases from 0.4 in 20 cm of water to 0.005 in 10 m of water. Synthesis of results from the new field observations with estimates from previous field and laboratory studies indicate that coral reef drag coefficients range from 0.2 to 0.005 and hydrodynamic roughnesses generally range from 2 to 8 cm. While coral reef drag coefficients depend on factors such as physical roughness and surface waves, a substantial fraction of the scatter in estimates of coral reef drag coefficients is due to variations in water depth.

Description: The Red Sea field program was supported by Awards USA 00002 and KSA 00011 made by KAUST to S. Lentz and J. Churchill. The Palau field program was funded by NSF Award OCE-1220529.

Description: Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 1367-1373, doi:10.1175/JPO-D-17-0185.1.

Description: An earlier study indicates that the side melting of icebergs subject to vertically homogeneous horizontal velocities is controlled by two distinct regimes, which depend on the melt plume behavior and produce a nonlinear dependence of side melt rate on velocity. Here, we extend this study to consider ice blocks melting in a two-layer vertically sheared flow in a laboratory setting. It is found that the use of the vertically averaged flow speed in current melt parameterizations gives an underestimate of the submarine side melt rate, in part because of the nonlinearity of the dependence of the side melt rate on flow speed but also because vertical shear in the horizontal velocity profile fundamentally changes the flow splitting around the ice block and consequently the velocity felt by the ice surface. An observational record of 90 icebergs in a Greenland fjord suggests that this effect could produce an average underestimate of iceberg side melt rates of 21%.

Description: A. F. was supported by NA14OAR4320106 from the National Oceanic and Atmospheric Administration, U.S. Department of Commerce. C. C. was supported by NSF OCE-1658079 and F. S. was supported by NSF OCE-1657601 and NSF PLR-1743693.

Description: 2018-12-12

Description: Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 31 (2018): 8059-8079, doi:10.1175/JCLI-D-17-0769.1.

Description: We use the method of least squares with Lagrange multipliers to fit an ocean general circulation model to the Multiproxy Approach for the Reconstruction of the Glacial Ocean Surface (MARGO) estimate of near sea surface temperature (NSST) at the Last Glacial Maximum (LGM; circa 23–19 thousand years ago). Compared to a modern simulation, the resulting global, last-glacial ocean state estimate, which fits the MARGO data within uncertainties in a free-running coupled ocean–sea ice simulation, has global-mean NSSTs that are 2°C lower and greater sea ice extent in all seasons in both the Northern and Southern Hemispheres. Increased brine rejection by sea ice formation in the Southern Ocean contributes to a stronger abyssal stratification set principally by salinity, qualitatively consistent with pore fluid measurements. The upper cell of the glacial Atlantic overturning circulation is deeper and stronger. Dye release experiments show similar distributions of Southern Ocean source waters in the glacial and modern western Atlantic, suggesting that LGM NSST data do not require a major reorganization of abyssal water masses. Outstanding challenges in reconstructing LGM ocean conditions include reducing effects from model biases and finding computationally efficient ways to incorporate abyssal tracers in global circulation inversions. Progress will be aided by the development of coupled ocean–atmosphere–ice inverse models, by improving high-latitude model processes that connect the upper and abyssal oceans, and by the collection of additional paleoclimate observations.

Description: DEA was supported by a NSF Graduate Research Fellowship and NSF Grant OCE-1060735. OM acknowledges support from the NSF. GF was supported by NASA Award 1553749 and Simons Foundation Award 549931.

Description: Published

Description: Wind is a major factor which induces oceanic currents and many theories including the Ekman theory have considered the wind induces currents. In this paper a numerical process has been used for forecasting of oceanic currents based on this theory. The survey has been done in an artificial five layer oceanic basin with smooth bottom of 120 meters, considering the geographic position of Persian Gulf. Primitive equations were solved on earth’s spherical coordinates system with sigma as vertical coordinate by finite element method. Vertical profile of predicted current vectors showed the complete formation of Ekman Spiral in the basin. This experimental simulation is a new approach for confirmation of Ekman Theory.

Description: Published

Description: W czerwcu 2001 roku mija osiemdziesiąt lat od powołania pierwszej polskiej placówki badań morza - Morskiego Laboratorium Rybackiego w Helu. Naukową opiekę nad Morskim Laboratorium Rybackim, początkowo podległym Morskiemu Urzędowi Rybackiemu w Wejherowie, sprawował Uniwersytet Poznański. Od 1925 roku Morskie Laboratorium Rybackie zostało podporządkowane Państwowemu Instytutowi Naukowemu Gospodarstwa Wiejskiego w Puławach, który podlegał z kolei Ministerstwu Rolnictwa. Sprawy przyszłości Laboratorium zaczęły się komplikować, kiedy w 1927 roku zagadnienia rybołówstwa morskiego przejęło Ministerstwo Przemysłu i Handlu, a w Warszawie w 1928 roku powołano stowarzyszenie Morski Instytut Rybacki subwencjonowane częściowo przez Ministerstwo Przemysłu i Handlu. W konsekwencji Morskie Laboratorium Rybackie znalazło się poza obszarem kompetencji zarówno Ministerstwa Przemysłu i Handlu, jak i Ministerstwa Rolnictwa, które redukując wydatki na badania naukowe w podległym mu Państwowym Instytucie Naukowym Gospodarstwa Wiejskiego, doprowadziło w 1931 roku do likwidacji Morskiego Laboratorium Rybackiego. Dobra materialne i intelektualne zlikwidowanego laboratorium przejęła Stacja Morska w Helu, powołana w 1932 roku w wyniku działań podjętych przez Ministerstwo Przemysłu i Handlu oraz Ministerstwo Wyznań Religijnych i Oświecenia Publicznego. W końcu 1938 roku Stacja Morska została przeniesiona do Gdyni. Po wojnie placówkę tę reaktywowano pod pierwotną nazwą Morskiego Laboratorium Rybackiego. W 1945 roku wznowiło również działalność stowarzyszenie Morski Instytut Rybacki pod komisarycznym zarządem państwowym, podporządkowe Ministerstwu Żeglugi. W 1949 roku nastąpiło włączenie Morskiego Laboratorium Rybackiego do Morskiego Instytutu Rybackiego, który przejął przedwojenną siedzibę Stacji Morskiej w Gdyni. Szczegółowy opis wszystkich perypetii organizacyjnych pierwszej polskiej placówki badań morza znajdą czytelnicy w oddawanej im właśnie do rąk pracy profesora Andrzeja Ropelewskiego. Pozwoliłem sobie na skrótowe przywołanie chronologii tych wydarzeń, aby wykazać, że pomimo licznych zmian instytucjonalnych i organizacyjnych w dziedzinie badań rybackich w Polsce zachowana została ich ciągłość oraz w pewnym zakresie również baza materialna, a tym samym istnieje uzasadnienie uroczystych obchodów jubileuszu osiemdziesięciolecia Morskiego Instytutu Rybackiego. Namawiając profesora Ropelewskiego do podjęcia się trudu przygotowania tej pozycji wydawniczej, zdawaliśmy sobie sprawę, że krąg ewentualnych odbiorców może ograniczać się do grona pracowników Morskiego Instytutu Rybackiego i ich rodzin, a przypuszczalnie również, choć w mniejszym stopniu, do ludzi związanych z polskim rybołówstwem w drugiej połowie ostatniego stulecia. Profesor Ropelewski ze skrupulatnością typową dla historyka stworzył nie tylko szczegółową kronikę wydarzeń z historii Morskiego Instytutu Rybackiego i jego pracowników, ale osadził ją w kontekście znacznie wykraczającym poza obszar spraw związanych z samym Instytutem i rybołówstwem. Mam więc nadzieję, że ta pozycja, adresowana początkowo do wąskiego grona czytelników, zamówiona i wydana dla uświetnienia Jubileuszu Instytutu, zainteresuje również szerszy krąg odbiorców. Mam tu na myśli tych wszystkich, którzy niekoniecznie byli lub są związani zawodowo z rybołówstwem, ale poczuwająsię do związków z szerzej pojmowaną gospodarką morską i nauką. Na przykładzie zmiennych kolei losu Morskiego Instytutu Rybackiego na przestrzeni omawianego osiemdziesięciolecia, obejmujących okresy rozwoju, stagnacji, a ostatnio stopniowego ograniczania zatrudnienia i zakresu działalności, baczny czytelnik zauważy zapewne analogie nie tylko do ogólnej sytuacji rybołówstwa, ale czasami również nauki, a nawet polityki morskiej państwa. Morski Instytut Rybacki był, jest i zapewne nadal będzie związany z rybołówstwem morskim. Doświadczenia osiemdziesięciu lat wykazują że to właśnie potrzeby tej branży w znacznym stopniu decydowały o wielkości zatrudnienia i profilu kadry naukowej Instytutu oraz tematyce i geograficznej lokalizacji prowadzonych badań. Ze względu na nieodwracalny spadek udziału i znaczenia połowów dalekomorskich polskiego rybołówstwa, a tym samym ograniczenie zasadniczych rejonów badań do Morza Bałtyckiego, przed Instytutem stoją w dalszym ciągu duże wyzwania. Wyzwania te przede wszystkim dotyczą konieczności sprostania nowym międzynarodowym wymogom związanym z przystępowaniem Polski do Unii Europejskiej. W największym uproszczeniu wymogi te dotyczą istotnej zmiany podejścia do badań rybackich, od dotychczasowych badań ukierunkowanych głównie na obiekt połowów - ryby, do badań interdyscyplinarnych obejmujących szeroki zakres relacji pomiędzy ekosystemem i rybołówstwem. Takie podejście promuje m. in. Międzynarodowa Rada Badań Morza i Organizacja do Spraw Wyżywienia i Rolnictwa Narodów Zjednoczonych. Zalecana zmiana profilu badań rybackich stanowić może szansę rozwoju Morskiego Instytutu Rybackiego, mimo zmniejszającej się roli rybołówstwa morskiego w gospodarce naszego kraju. W okresie osiemdziesięciu.lat swojej działalności MIR stał się instytucją, której dokonania znane są w kraju i zagranicą. Pomimo ogólnie znanych trudności finansowych nauki polskiej potencjał materialny i intelektualny Instytutu, tworzony przez tak długi okres, pozwala zachować pewien optymizm na przyszłość i mieć nadzieję, że nie zostanie on zmarnowany.

Description: Published

Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Semper, S., Vage, K., Pickart, R. S., Valdimarsson, H., Torres, D. J., & Jonsson, S. The emergence of the North Icelandic Jet and its evolution from northeast Iceland to Denmark Strait. Journal of Physical Oceanography, 49(10), (2019): 2499-2521, doi:10.1175/JPO-D-19-0088.1.

Description: The North Icelandic Jet (NIJ) is an important source of dense water to the overflow plume passing through Denmark Strait. The properties, structure, and transport of the NIJ are investigated for the first time along its entire pathway following the continental slope north of Iceland, using 13 hydrographic/velocity surveys of high spatial resolution conducted between 2004 and 2018. The comprehensive dataset reveals that the current originates northeast of Iceland and increases in volume transport by roughly 0.4 Sv (1 Sv ≡ 106 m3 s−1) per 100 km until 300 km upstream of Denmark Strait, at which point the highest transport is reached. The bulk of the NIJ transport is confined to a small area in Θ–S space centered near −0.29° ± 0.16°C in Conservative Temperature and 35.075 ± 0.006 g kg−1 in Absolute Salinity. While the hydrographic properties of this transport mode are not significantly modified along the NIJ’s pathway, the transport estimates vary considerably between and within the surveys. Neither a clear seasonal signal nor a consistent link to atmospheric forcing was found, but barotropic and/or baroclinic instability is likely active in the current. The NIJ displays a double-core structure in roughly 50% of the occupations, with the two cores centered at the 600- and 800-m isobaths, respectively. The transport of overflow water 300 km upstream of Denmark Strait exceeds 1.8 ± 0.3 Sv, which is substantially larger than estimates from a year-long mooring array and hydrographic/velocity surveys closer to the strait, where the NIJ merges with the separated East Greenland Current. This implies a more substantial contribution of the NIJ to the Denmark Strait overflow plume than previously envisaged.

Description: Six different research vessels were involved in the collection of the data used in this study: RRS James Clark Ross, R/V Knorr, R/V Bjarni Sæmundsson, R/V Håkon Mosby, NRV Alliance, and R/V Kristine Bonnevie. We thank the captain and crew of each of these vessels for their hard work as well as the many watch standers who have sailed on the cruises and helped collect the measurements. We also thank Frank Bahr for processing the VMADCP data collected on NRV Alliance and Magnús Danielsen for the processing of the hydrographic data collected on R/V Bjarni Sæmundsson. We acknowledge Leah Trafford McRaven for assistance with Fig. 1 and two anonymous reviewers for their helpful comments, which improved the manuscript. Funding for the project was provided by the Bergen Research Foundation Grant BFS2016REK01 (K. Våge and S. Semper), the Norwegian Research Council under Grant Agreement 231647 (K. Våge), and the U.S. National Science Foundation Grants OCE-1259618 and OCE-1756361 (R. S. Pickart and D. J. Torres), as well as OCE-1558742 (R. S. Pickart). The dataset is available on PANGAEA under https://doi.pangaea.de/10.1594/PANGAEA.903535.

Description: Author Posting. © American Meteorological Society, 2019. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of the Atmospheric and Oceanic Technology 36(10), (2019): 1997-2014, doi: 10.1175/JTECH-D-19-0029.1.

Description: While land-based high-frequency (HF) radars are the only instruments capable of resolving both the temporal and spatial variability of surface currents in the coastal ocean, recent high-resolution views suggest that the coastal ocean is more complex than presently deployed radar systems are able to reveal. This work uses a hybrid system, having elements of both phased arrays and direction finding radars, to improve the azimuthal resolution of HF radars. Data from two radars deployed along the U.S. East Coast and configured as 8-antenna grid arrays were used to evaluate potential direction finding and signal, or emitter, detection methods. Direction finding methods such as maximum likelihood estimation generally performed better than the well-known multiple signal classification (MUSIC) method given identical emitter detection methods. However, accurately estimating the number of emitters present in HF radar observations is a challenge. As MUSIC’s direction-of-arrival (DOA) function permits simple empirical tests that dramatically aid the detection process, MUSIC was found to be the superior method in this study. The 8-antenna arrays were able to provide more accurate estimates of MUSIC’s noise subspace than typical 3-antenna systems, eliminating the need for a series of empirical parameters to control MUSIC’s performance. Code developed for this research has been made available in an online repository.

Description: This analysis was supported by NSF Grants OCE-1657896 and OCE-1736930 to Kirincich, OCE-1658475 to Emery and Washburn and OCE-1736709 to Flament. Flament is also supported by NOAA’s Integrated Ocean Observing System through Award NA11NOS0120039. The authors thank Lindsey Benjamin, Alma Castillo, Ken Constantine, Benedicte Dousset, Ian Fernandez, Mael Flament, Dave Harris, Garrett Hebert, Ben Hodges, Victoria Futch, Matt Guanci, and Philip Moravcik for assistance in building, deploying, and operating the radars.

Description: 2020-04-11

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2019.

Description: The Earth's oceans holds a wealth of information currently hidden from us. Effective measurement of its properties could provide a better understanding of our changing climate and insights into the creatures that inhabit its waters. Autonomous underwater vehicles (AUVs) hold the promise of penetrating the ocean environment and uncovering its mysteries; and progress in underwater robotics research over the past three decades has resulted in vehicles that can navigate reliably and operate consistently, providing oceanographers with an additional tool for studying the ocean. Unfortunately, the high cost of these vehicles has stifled the democratization of this technology. We believe that this is a consequence of two factors. Firstly, reliable navigation on conventional AUVs has been achieved through the use of a sophisticated sensor system, namely the Doppler velocity log (DVL)-aided inertial navigation system (INS), which drives up vehicle cost, power use and size. Secondly, deployment of these vehicles is expensive and unwieldy due to their complexity, size and cost, resulting in the need for specialized personnel for vehicle operation and maintenance. The recent development of simpler, low-cost, miniature underwater robots provides a solution that mitigates both these factors; however, removing the expensive DVL-aided INS means that they perform poorly in terms of navigation accuracy. We address this by introducing a novel acoustic system that enables AUV self-localization without requiring a DVL-aided INS or on-board active acoustic transmitters. We term this approach Passive Inverted Ultra-Short Baseline (piUSBL) positioning. The system uses a single acoustic beacon and a time-synchronized, vehicle-mounted, passive receiver array to localize the vehicle relative to this beacon. Our approach has two unique advantages: first, a single beacon lowers cost and enables easy deployment; second, a passive receiver allows the vehicle to be low-power, low-cost and small, and enables multi-vehicle scalability. Providing this new generation of small and inexpensive vehicles with accurate navigation can potentially lower the cost of entry into underwater robotics research and further its widespread use for ocean science. We hope that these contributions in low-cost underwater navigation will enable the ubiquitous and coordinated use of robots to explore and understand the underwater domain.

Description: This research was funded and supported by a number of sponsors; we gratefully acknowledge them below. Defense Advanced Research Projects Agency (DARPA) and SSC Pacific via Applied Physical Sciences Corp. (APS) under contract number N66001-11-C-4115. SSC Pacific via Applied Physical Sciences Corp. (APS) under award number N66001-14-C-4031. Air Force via Lincoln Laboratory under award number FA8721-05-C-0002. Office of Naval Research (ONR) via University of California-San Diego under award number N00014-13-1-0632. Defense Advanced Research Projects Agency (DARPA) via Applied Physical Sciences Corp. (APS) under award number HR0011-18-C-0008. Office of Naval Research (ONR) under award number N00014-17-1-2474.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2018.

Description: The biological carbon pump (BCP) helps to moderate atmospheric carbon dioxide levels by bringing carbon to the deep ocean, where it can be sequestered on timescales of centuries to millennia. Climate change is predicted to decrease the efficiency of the global BCP, however, the magnitude and timescale of this shift is largely uncertain and will likely impact some areas of the global ocean more significantly than others. Therefore, it is imperative that we (1) accurately quantify surface export and remineralization of particulate organic carbon (POC) via the BCP over large regions of the global ocean, (2) examine the factors controlling these POC fluxes and their variability, which includes the cycling of biologically-relevant trace metals, and (3) establish if and how the BCP is changing over time. This thesis focuses on addressing various aspects of these objectives using the 234Th-238U method across basin-scale GEOTRACES transects. First, the export and remineralization of POC were examined across large gradients in productivity, upwelling, community structure, and dissolved oxygen in the southeastern tropical Pacific Ocean. Although low oxygen zones are traditionally thought to have decreased POC flux attenuation relative to other regions of the global ocean and the low oxygen Pacific locations followed this pattern, regions that were functionally anoxic had enhanced attenuation in the upper 400 m. Second, trace metal export and remineralization were quantified across the Pacific transect. Because many trace metals are necessary for the metabolic functions of marine organisms and can co-limit marine productivity, the controls on the cycling of trace metals in the upper ocean were examined. Lastly, POC export was determined across two transects in the Western Arctic Ocean, where light and nutrient availability drive the biological pump. Upper ocean export estimates in the central basin did not reflect a substantial change in the biological pump compared to studies from the last three decades, however, an extensive maximum in 234Th relative to 238U deeper in the water column indicated that rapid vertical transport had occurred, which could suggest a more efficient biological pump in the Arctic Ocean.

Description: I was funded under the NASA Earth and Space Science Fellowship Program grant (NNX13AP31H) for three years. I was also funded for work on the U.S. Pacific and Arctic GEOTRACES campaigns under two National Science Foundation grants (OCE-1232669 and OCE- 1458305). The MIT Henry G. Houghton Fund provided support for the purchase of computers and textbooks and the MIT Scurlock Fund allowed for my travel to Bermuda for cruise training. WHOI Academic Programs supplemented the aforementioned funding and also provided additional support for travel to conferences.

Description: Author Posting. © American Meteorological Society, 2017. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 47 (2017): 2631-2646, doi:10.1175/JPO-D-17-0062.1.

Description: Data from a mooring array deployed north of Denmark Strait from September 2011 to August 2012 are used to investigate the structure and variability of the shelfbreak East Greenland Current (EGC). The shelfbreak EGC is a surface-intensified current situated just offshore of the east Greenland shelf break flowing southward through Denmark Strait. This study identified two dominant spatial modes of variability within the current: a pulsing mode and a meandering mode, both of which were most pronounced in fall and winter. A particularly energetic event in November 2011 was related to a reversal of the current for nearly a month. In addition to the seasonal signal, the current was associated with periods of enhanced eddy kinetic energy and increased variability on shorter time scales. The data indicate that the current is, for the most part, barotropically stable but subject to baroclinic instability from September to March. By contrast, in summer the current is mainly confined to the shelf break with decreased eddy kinetic energy and minimal baroclinic conversion. No other region of the Nordic Seas displays higher levels of eddy kinetic energy than the shelfbreak EGC north of Denmark Strait during fall. This appears to be due to the large velocity variability on mesoscale time scales generated by the instabilities. The mesoscale variability documented here may be a source of the variability observed at the Denmark Strait sill.

Description: Support for this work was provided by the Norwegian Research Council under Grant Agreement 231647 (LH and KV) and the Bergen Research Foundation under Grant BFS2016REK01 (KV). Additional funding was provided by the National Science Foundation under Grants OCE-0959381 and OCE-1558742 (RP).

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2018

Description: In the ocean, chromium (Cr) is a redox-sensitive trace metal. The reduction of Cr(VI) to Cr(III) occurs in oxygen deficient zones (ODZs), and Cr reduction in general has been identified as a significant Cr isotope fractionation mechanism. This thesis presents the first Cr isotope variations (d53Cr) in ODZs of the ocean and adds to the sparse Cr isotope data published for modern seawater. I developed a precise and accurate Cr isotope method for seawater samples. Seawater acidification converts total Cr to Cr(III) which is preconcentrated by Mg(OH)2 coprecipitation. A three-column anion exchange chromatography scheme separates Cr from isobaric and polyatomic interferences present in the seawater and reagent matrixes. Isotope analysis is performed on a MC-ICP-MS IsoProbe. The addition of a 50Cr-54Cr double spike allows for accurate correction of procedural and instrumental Cr mass fractionations. The first Cr isotope ratio data for a full water column profile in the Pacific Ocean is presented. This station serves as a fully oxic counterpart to stations located within the ODZ of the Eastern Tropical North Pacific. At one station, Cr concentrations are lower and d53Cr values are heavier within the ODZ. This is consistent with Cr reduction resulting in isotopically lighter, particlereactive Cr(III), which is scavenged and exported from the water column. A strong correlation of d53Cr and d15NNO3- at this station suggests that Cr reduction may be microbially mediated instead of simply being a product of thermodynamic equilibrium. Alternatively, Cr may be reduced by Fe(II). In the anoxic bottom waters of the Santa Barbara Basin a strong Cr reduction signal (lower [Cr], heavier d53Cr) is observed, which may result from the same aforementioned Cr reduction mechanisms. A shift to the heaviest seawater Cr isotope signatures yet observed was detected in the oxic bottom waters of the shallow Arctic Chukchi shelf, while Cr concentrations decreased. This extreme isotope signal may result from Cr reduction by a reduced species (e.g. Fe(II)), which was released from the underlying anoxic shelf sediments. Cr in the Atlantic layer and in the bottom water of a central Arctic station appears to be shaped by a novel, unidentified process.

Description: This research was supported by the US National Science Foundation (NSF Award No. OCE- 0926197, OCE-1233749, OCE-1357224), the Singapore National Research Foundation through the Singapore-MIT Alliance for Research and Technology (Award No. WBS 6916070), and the Center for Microbial Research and Education (NSF-OIA Award No. EF-0424599). In the last year of my studies, I was supported by a MIT-WHOI Joint Program Science Fellowship.

Description: Author Posting. © American Meteorological Society, 2017. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 34 (2017): 1713-1721, doi:10.1175/JTECH-D-16-0258.1.

Description: Data collected with acoustic Doppler current profilers installed on CTD rosettes and lowered through the water column [lowered ADCP (LADCP) systems] are routinely used to derive full-depth profiles of ocean velocity. In addition to the uncertainties arising from random noise in the along-beam velocity measurements, LADCP-derived velocities are commonly contaminated by bias errors due to imperfectly measured instrument attitude (heading, pitch, and roll). Of particular concern are the heading measurements, because it is not usually feasible to calibrate the internal ADCP compasses with the instruments installed on a CTD rosette, away from the magnetic disturbances of the ship. Heading data from dual-headed LADCP systems, which consist of upward- and downward-pointing ADCPs installed on the same rosette, commonly indicate heading-dependent compass errors with amplitudes exceeding 10°. In an attempt to reduce LADCP velocity errors, several dozen profiles of simultaneous LADCP and magnetometer/accelerometer data were collected in the Gulf of Mexico. Agreement between the LADCP profiles and simultaneous shipboard velocity measurements improves significantly when the former are processed with external attitude measurements. Another set of LADCP profiles with external attitude data was collected in a region of the Arctic Ocean where the horizontal geomagnetic field is too weak for the ADCP compasses to work reliably. Good agreement between shipboard velocity measurements and Arctic LADCP profiles collected at magnetic dip angles exceeding and processed with external attitude measurements indicate that high-quality velocity profiles can be obtained close to the magnetic poles.

Description: Part of this research was made possible by a grant from the Gulf of Mexico Research Initiative to support the Ecosystem Impacts of Oil and Gas Inputs to the Gulf (ECOGIG-2) research consortium. Funding for acquisition of the 2015 Arctic data was provided by NSF (1203473 and 1249133) and NOAA (NA15OAR4310155) under the NABOS-II program.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physical Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2019.

Description: Global patterns of ocean salinity arise from the exchange of freshwater between the sea surface and the atmosphere. For a quasi-steady state system, these surface fluxes are balanced by compensating transports of salt in the ocean interior. In a warming climate, the atmosphere holds additional water vapor which acts to intensify the global water cycle. Amplified freshwater fluxes are then absorbed at the surface and propagate along ocean circulation pathways. Here, we use coupled model results from the CMIP5 experiment to identify coherent responses in the atmospheric water cycle and in ocean salinity patterns. Some aspects of the response are consistent across models, while other regions show large inter-model spread. In particular, the salinity response in the North Atlantic subpolar gyre, where the mean salinity plays a role in maintaining high surface density for deep-water formation, has low confidence in CMIP5 models. To understand how differences in ocean circulation may affect this response, we use two techniques to diagnose the role of salt transports in the present-day climate. The first is a salt budget within the surface mixed layer, which identifies major transport processes. The second is a Lagrangian particle tracking tool, used to understand the regional connectivity of water masses. From this analysis, we find that anomalous freshwater signals become well mixed within the ocean gyres, but can be isolated on larger scales. The subpolar Atlantic salinity response generally shows freshening at the surface, but is sensitive to the transport of anomalously salty water from the subtropics, a largely eddy-driven process. As CMIP5 models use a range of eddy parameterizations, this is likely a source of uncertainty in the salinity response. Finally, we investigate the effect of salinity changes on the deep overturning cells and other circulations, and find a complex influence that also depends on the details of advective pathways. In a warming scenario, water cycle amplification actually works to strengthen the Atlantic meridional overturning circulation due to the influence of enhanced subtropical evaporation.

Description: Funding for this thesis was provided by NASA grant NNX12AF59GS03, a NASA Earth and Space Science Fellowship award 80NSSC17K0372, and the WHOI Academic Programs Office.

Description: Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 121 (2016): 8670–8688, doi:10.1002/2016JC011764.

Description: Discharge of surface-derived meltwater at the submerged base of Greenland's marine-terminating glaciers creates subglacial discharge plumes that rise along the glacier/ocean interface. These plumes impact submarine melting, calving, and fjord circulation. Observations of plume properties and dynamics are challenging due to their proximity to the calving edge of glaciers. Therefore, to date information on these plumes has been largely derived from models. Here we present temperature, salinity, and velocity data collected in a plume that surfaced at the edge of Saqqarliup Sermia, a midsized Greenlandic glacier. The plume is associated with a narrow core of rising waters approximately 20 m in diameter at the ice edge that spreads to a 200 m by 300 m plume pool as it reaches the surface, before descending to its equilibrium depth. Volume flux estimates indicate that the plume is primarily driven by subglacial discharge and that this has been diluted in a ratio of 1:10 by the time the plume reaches the surface. While highly uncertain, meltwater fluxes are likely 2 orders of magnitude smaller than the subglacial discharge flux. The overall plume characteristics agree with those predicted by theoretical plume models for a convection-driven plume with limited influence from submarine melting.

Description: National Science Foundation (NSF) Grant Numbers: PLR-1418256 , OCE-1434041; Woods Hole Oceanographic Institution (WHOI) Ocean and Climate Change Institute (OCCI) Arctic Research Initiative OCCI; National Aeronautics and Space Administration Grant Number: NNX10AN83H

Description: 2017-06-15

Description: Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography: Methods 15 (2017): 495-502, doi:10.1002/lom3.10177.

Description: An Aanderaa Data Instruments 4831 Oxygen optode was configured on an underwater glider such that the optode extended into the atmosphere during each glider surface interval enabling in situ calibration of the sensor by directly measuring the known partial pressure of the atmosphere. The approach, which has previously been implemented on profiling floats but not on gliders, was tested during a 15-day deployment at the New England shelf break in June 2016, a productive period during which surface O2 saturation averaged 110%. Results were validated by shipboard Winkler O2 calibration casts, which were used to determine a sensor gain factor of 1.055 ± 0.004. Consistent with profiling float observations, air measurements contain contamination from splashing water and/or residual seawater on the sensor face. Glider surface measurements were determined to be a linear combination of 36% of surface water and 64% atmospheric air. When correcting air measurements for this effect, a sensor gain correction of 1.055 ± 0.005 was calculated based on comparing glider air measurements to the expected atmospheric pO2 calculated from atmospheric pressure and humidity data from a nearby NOAA buoy. Thus, the two approaches were in agreement and were both demonstrated to be accurate to within ±0.5%. We expect uncertainty in the air-calibration could be further reduced by increasing the vertical positioning of the optode, lengthening deployment time, or operating in waters with surface O2 saturation closer to equilibrium.

Description: Author Posting. © American Meteorological Society, 2017. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 29-44, doi:10.1175/JPO-D-17-0016.1.

Description: The cospectrum of the horizontal and vertical turbulent velocity fluctuations, an essential tool for understanding measurements of the turbulent Reynolds shear stress, often departs in the ocean from the shape that has been established in the atmospheric surface layer. Here, we test the hypothesis that this departure is caused by advection of standard boundary layer turbulence by the random oscillatory velocities produced by surface gravity waves. The test is based on a model with two elements. The first is a representation of the spatial structure of the turbulence, guided by rapid distortion theory, and consistent with the one-dimensional cospectra that have been measured in the atmosphere. The second model element is a map of the spatial structure of the turbulence to the temporal fluctuations measured at fixed sensors, assuming advection of frozen turbulence by the velocities associated with surface waves. The model is adapted to removal of the wave velocities from the turbulent fluctuations using spatial filtering. The model is tested against previously published laboratory measurements under wave-free conditions and two new sets of measurements near the seafloor in the coastal ocean in the presence of waves. Although quantitative discrepancies exist, the model captures the dominant features of the laboratory and field measurements, suggesting that the underlying model physics are sound.

Description: This research was supported by National Science Foundation Ocean Sciences Division Award 1356060 and the U.S. Geological Survey Coastal and Marine Geology Program.

Description: Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Earth and Space Science, 6(7), (2019): 1220-1233, doi:10.1029/2018EA000436.

Description: Ocean evaporative fluxes are a critical component of the Earth's energy and water cycle, but their estimation remains uncertain. Near‐surface humidity is a required input to bulk flux algorithms that relate mean surface values to the turbulent fluxes. Several satellite‐derived turbulent flux products have been developed over the last decade that utilize passive microwave imager observations to estimate the surface humidity. It is known, however, that these estimates tend to diverge from one another and from in situ observations. Analysis of current state‐of‐the‐art satellite estimates provided herein reveals that regional‐scale biases in these products remain significant. Investigations reveal a link between the spatial coherency of the observed biases to atmospheric dynamical controls of water vapor vertical stratification, cloud liquid water, and sea surface temperature. This information is used to develop a simple state‐dependent bias correction that results in more consistent ocean surface humidity estimates. A principal conclusion is that further improvements to ocean near‐surface humidity estimation using microwave radiometers requires incorporation of prior information on water vapor stratification and sea surface temperature.

Description: Data products used in this study are made publicly available via multiple repositories hosted by individual data product producers. JOFUROv2 and JOFUROv3 data are available online (https://j‐ofuro.scc.u‐tokai.ac.jp/en/). IFREMERv4 and NOCS surface data are available through the OceanHeatFlux project (https://www.ifremer.fr/oceanheatflux/Data). GSSTFv3 (doi:10.5067/MEASURES/GSSTF/DATA301) and MERRA‐2 data are obtained from the Goddard Earth Sciences Data and Information Services Center. HOAPSv3.2 data are available from Satellite Application Facility on Climate Monitoring (https://doi.org/10.5676/EUM_SAF_CM/HOAPS/V001). SEAFLUXv2 data are accessed through the National Centers for Environmental Information (http://doi.org/10.7289/V59K4885). Daily surface observations were provided by David Berry and Elizabeth Kent. This work is supported under the NASA Physical Oceanography Program Grant NNX14AK48A.

Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Roemmich, D., Alford, M. H., Claustre, H., Johnson, K., King, B., Moum, J., Oke, P., Owens, W. B., Pouliquen, S., Purkey, S., Scanderbeg, M., Suga, T., Wijffels, S., Zilberman, N., Bakker, D., Baringer, M., Belbeoch, M., Bittig, H. C., Boss, E., Calil, P., Carse, F., Carval, T., Chai, F., Conchubhair, D. O., d'Ortenzio, F., Dall'Olmo, G., Desbruyeres, D., Fennel, K., Fer, I., Ferrari, R., Forget, G., Freeland, H., Fujiki, T., Gehlen, M., Greenan, B., Hallberg, R., Hibiya, T., Hosoda, S., Jayne, S., Jochum, M., Johnson, G. C., Kang, K., Kolodziejczyk, N., Kortzinger, A., Le Traon, P., Lenn, Y., Maze, G., Mork, K. A., Morris, T., Nagai, T., Nash, J., Garabato, A. N., Olsen, A., Pattabhi, R. R., Prakash, S., Riser, S., Schmechtig, C., Schmid, C., Shroyer, E., Sterl, A., Sutton, P., Talley, L., Tanhua, T., Thierry, V., Thomalla, S., Toole, J., Troisi, A., Trull, T. W., Turton, J., Velez-Belchi, P. J., Walczowski, W., Wang, H., Wanninkhof, R., Waterhouse, A. F., Waterman, S., Watson, A., Wilson, C., Wong, A. P. S., Xu, J., & Yasuda, I. On the future of Argo: A global, full-depth, multi-disciplinary array. Frontiers in Marine Science, 6, (2019): 439, doi:10.3389/fmars.2019.00439.

Description: The Argo Program has been implemented and sustained for almost two decades, as a global array of about 4000 profiling floats. Argo provides continuous observations of ocean temperature and salinity versus pressure, from the sea surface to 2000 dbar. The successful installation of the Argo array and its innovative data management system arose opportunistically from the combination of great scientific need and technological innovation. Through the data system, Argo provides fundamental physical observations with broad societally-valuable applications, built on the cost-efficient and robust technologies of autonomous profiling floats. Following recent advances in platform and sensor technologies, even greater opportunity exists now than 20 years ago to (i) improve Argo’s global coverage and value beyond the original design, (ii) extend Argo to span the full ocean depth, (iii) add biogeochemical sensors for improved understanding of oceanic cycles of carbon, nutrients, and ecosystems, and (iv) consider experimental sensors that might be included in the future, for example to document the spatial and temporal patterns of ocean mixing. For Core Argo and each of these enhancements, the past, present, and future progression along a path from experimental deployments to regional pilot arrays to global implementation is described. The objective is to create a fully global, top-to-bottom, dynamically complete, and multidisciplinary Argo Program that will integrate seamlessly with satellite and with other in situ elements of the Global Ocean Observing System (Legler et al., 2015). The integrated system will deliver operational reanalysis and forecasting capability, and assessment of the state and variability of the climate system with respect to physical, biogeochemical, and ecosystems parameters. It will enable basic research of unprecedented breadth and magnitude, and a wealth of ocean-education and outreach opportunities.

Description: DR, MS, and NZ were supported by the US Argo Program through the NOAA Grant NA15OAR4320071 (CIMEC). WO, SJ, and SWi were supported by the US Argo Program through the NOAA Grant NA14OAR4320158 (CINAR). EuroArgo scientists were supported by the two grants: (1) AtlantOS funding by the European Union’s Horizon 2020 Research and Innovation Programme under the Grant Agreement No. 633211 and (2) Monitoring the Oceans and Climate Change with Argo (MOCCA) Co-funded by the European Maritime and Fisheries Fund (EMFF) Project No. SI2.709624. This manuscript represents a contribution to the following research projects for HC, CaS, and FD: remOcean (funded by the European Research Council, grant 246777), NAOS (funded by the Agence Nationale de la Recherche in the frame of the French “Equipement d’avenir” program, grant ANR J11R107-F), AtlantOS (funded by the European Union’s Horizon 2020 Research and Innovation Programme, grant 2014-633211), and the BGC-Argo project funded by the CNES. DB was funded by the EU RINGO project (730944 H2020-INFRADEV-2016-1). RF was supported by the AGS-1835576. GCJ was supported by the Global Ocean Monitoring and Observing Program, National Oceanic and Atmospheric Administration (NOAA), U.S., and the Department of Commerce and NOAA Research. LT was funded under the SOCCOM Grant No. NSF PLR-1425989. VT’s contribution was supported by the French National Research Agency (ANR) through the EQUIPEX NAOS (Novel Argo Observing System) under the reference ANR-10-EQPX-40 and by the European H2020 Research and Innovation Programme through the AtlantOS project under the reference 633211. WW was supported by the Argo Poland program through the Ministry of Sciences and Higher Education Grant No. DIR/WK/2016/12. AmW was funded by the NSF-OCE1434722. K-RK is funded by the National Institute of Meteorological Sciences’ Research and Development Program “Development of Marine Meteorology Monitoring and Next-generation Ocean Forecasting System” under the grant KMA2018-00421. CSchmid is funded by NOAA/AOML and the US Argo Program through NOAA/OOMD. MBa is funded by NOAA/AOML.

Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Tanhua, T., Pouliquen, S., Hausman, J., O'Brien, K., Bricher, P., de Bruin, T., Buck, J. J. H., Burger, E. F., Carval, T., Casey, K. S., Diggs, S., Giorgetti, A., Glaves, H., Harscoat, V., Kinkade, D., Muelbert, J. H., Novellino, A., Pfeil, B., Pulsifer, P. L., Van de Putte, A., Robinson, E., Schaap, D., Smirnov, A., Smith, N., Snowden, D., Spears, T., Stall, S., Tacoma, M., Thijsse, P., Tronstad, S., Vandenberghe, T., Wengren, M., Wyborn, L., & Zhao, Z. Ocean FAIR data services. Frontiers in Marine Science, 6, (2019): 440, doi:10.3389/fmars.2019.00440.

Description: Well-founded data management systems are of vital importance for ocean observing systems as they ensure that essential data are not only collected but also retained and made accessible for analysis and application by current and future users. Effective data management requires collaboration across activities including observations, metadata and data assembly, quality assurance and control (QA/QC), and data publication that enables local and interoperable discovery and access and secures archiving that guarantees long-term preservation. To achieve this, data should be findable, accessible, interoperable, and reusable (FAIR). Here, we outline how these principles apply to ocean data and illustrate them with a few examples. In recent decades, ocean data managers, in close collaboration with international organizations, have played an active role in the improvement of environmental data standardization, accessibility, and interoperability through different projects, enhancing access to observation data at all stages of the data life cycle and fostering the development of integrated services targeted to research, regulatory, and operational users. As ocean observing systems evolve and an increasing number of autonomous platforms and sensors are deployed, the volume and variety of data increase dramatically. For instance, there are more than 70 data catalogs that contain metadata records for the polar oceans, a situation that makes comprehensive data discovery beyond the capacity of most researchers. To better serve research, operational, and commercial users, more efficient turnaround of quality data in known formats and made available through Web services is necessary. In particular, automation of data workflows will be critical to reduce friction throughout the data value chain. Adhering to the FAIR principles with free, timely, and unrestricted access to ocean observation data is beneficial for the originators, has obvious benefits for users, and is an essential foundation for the development of new services made possible with big data technologies.

Description: We thank the funding agencies and the data management projects that have made this work possible through dedicated funding for the data management activities and improvements. TT and JB acknowledge support from the EU Horizon 2020 project AtlantOS (grant agreement 633211). JM acknowledges support from the Integrated Oceanography and Multiple Uses of the Continental Shelf and the Adjacent Ocean Integrated Center of Oceanography (INCT-Mar COI, CNPq, Proc. 565062/2010-7). DS acknowledges support from the H2020 project SeaDataCloud (grant agreement 730960). SP acknowledges support from the EU Horizon 2020 project ENVRIplus (grant agreement 654182). AN acknowledges support from the EMODnet Physics (grant number EASME/EMFF/2016/1.3.1.2-Lot3/SI2.749411). HG acknowledges funding from the EU H2020 Ocean Data Interoperability Platform (ODIP) project (Grant No: 654310). JH acknowledges that funding came from the National Aeronautics and Space Agency as managed by the California Institute of Technology under task number 80NM0018F0848. AVdP acknowledges support from Belspo in the framework the EU Lifewatch ERIC (grant agreement FR/36/AN3). KO’B acknowledges that his publication is partially funded by the Joint Institute for the Study of the Atmosphere and Ocean (JISAO) under NOAA Cooperative Agreement NA15OAR4320063, Contribution No. 2018-0175.

Description: Author(s): Markus Schmitt and Stefan Kehrein The notion of a dynamical quantum phase transition (DQPT) was recently introduced [Heyl et al. , Phys. Rev. Lett. 110 , 135704 (2013) ] as the nonanalytic behavior of the Loschmidt echo at critical times in the thermodynamic limit. In this work the quench dynamics in the ground state sector of the two… [Phys. Rev. B 92, 075114] Published Mon Aug 10, 2015

Description: Author(s): Yuhe Zhang, G. J. Sreejith, and J. K. Jain The possibility of realizing bosonic fractional quantum Hall effect in ultracold atomic systems suggests a new route to producing and manipulating anyons, by introducing auxiliary bosons of a different species that capture quasiholes and thus inherit their nontrivial braiding properties. States with… [Phys. Rev. B 92, 075116] Published Mon Aug 10, 2015

Description: Author(s): Y. Wang, K. Wohlfeld, B. Moritz, C. J. Jia, M. van Veenendaal, K. Wu, C.-C. Chen, and T. P. Devereaux Using cluster perturbation theory, we explain the origin of the strongly dispersive feature found at high binding energy in the spectral function of the Hubbard model. By comparing the Hubbard and t − J − 3 s model spectra, we show that this dispersion does not originate from either coupling to spin fluc… [Phys. Rev. B 92, 075119] Published Mon Aug 10, 2015

Description: Author(s): Kengo Fushiya, Ryoichi Miyazaki, Ryuji Higashinaka, Akira Yamada, Masaichiro Mizumaki, Satoshi Tsutsui, Kiyofumi Nitta, Tomoya Uruga, Bunya Suemitsu, Hideyuki Sato, and Yuji Aoki We have measured x-ray absorption spectra at the Sm L 3 edge to investigate the Sm-ion valence of ( S m x L a 1 − x ) O s 4 S b 12 , in which field-insensitive heavy-fermion behavior appears at low temperatures for x = 1 . It has been found that the Sm-ion valance shifts to 2 + with La ion substitution; from v = + 2.78 ( x = 1 ) … [Phys. Rev. B 92, 075118] Published Mon Aug 10, 2015

Description: Author(s): Su-Yang Xu, Chang Liu, I. Belopolski, S. K. Kushwaha, R. Sankar, J. W. Krizan, T.-R. Chang, C. M. Polley, J. Adell, T. Balasubramanian, K. Miyamoto, N. Alidoust, Guang Bian, M. Neupane, H.-T. Jeng, C.-Y. Huang, W.-F. Tsai, T. Okuda, A. Bansil, F. C. Chou, R. J. Cava, H. Lin, and M. Z. Hasan A three-dimensional (3D) Dirac semimetal is a novel state of quantum matter which has recently attracted much attention as an apparent 3D version of graphene. In this paper, we report results on the electronic structure of the 3D Dirac semimetal Na 3 Bi at a surface that reveals its nontrivial ground … [Phys. Rev. B 92, 075115] Published Mon Aug 10, 2015

Description: Author(s): Christophe Mora, Cătălin Paşcu Moca, Jan von Delft, and Gergely Zaránd We generalize Nozières' Fermi-liquid theory for the low-energy behavior of the Kondo model to that of the single-impurity Anderson model. In addition to the electrons' phase shift at the Fermi energy, the low-energy Fermi-liquid theory is characterized by four Fermi-liquid parameters: the two given … [Phys. Rev. B 92, 075120] Published Mon Aug 10, 2015

Description: Author(s): S. Thiess, T.-L. Lee, C. Aruta, C. T. Lin, F. Venturini, N. B. Brookes, B. C. C. Cowie, and J. Zegenhagen We analyzed the valence band (VB) of the 90 K high-temperature superconductor YBa 2 Cu 3 O 7 − δ by photoelectron spectroscopy under standing-wave excitation employing hard x rays. Precisely positioning the standing-wave intensity in the unit cell allows selectively probing the VB yield from the CuO chains… [Phys. Rev. B 92, 075117] Published Mon Aug 10, 2015

Description: Author(s): Beom Hyun Kim and Jeroen van den Brink The recent discovery that resonant inelastic x-ray scattering can probe single-magnon (SM) dispersions in transition metal (TM) oxides when the x-ray energy is tuned to the TM L edge has put this technique on a par with inelastic neutron scattering. It is generally presumed that selection rules forb… [Phys. Rev. B 92, 081105(R)] Published Mon Aug 10, 2015

Description: Author(s): Erik G. C. P. van Loon, Mikhail I. Katsnelson, and Mikhail Lemeshko We use the dual boson approach to reveal the phase diagram of the Fermi-Hubbard model with long-range dipole-dipole interactions. By using a large-scale finite-temperature calculation on a 64 × 64 square lattice we demonstrate the existence of a novel phase, possessing an “ultralong-range” order. The … [Phys. Rev. B 92, 081106(R)] Published Mon Aug 10, 2015

Description: Author(s): Jing Wang, Biao Lian, Xiao-Liang Qi, and Shou-Cheng Zhang Motivated by the possibility of experimental detection of the topological magnetoelectric effect the authors put forth a theoretical proposal for its realization in the zero plateau quantum anomalous Hall state of a ferromagnet-topological insulator heterostructure. [Phys. Rev. B 92, 081107(R)] Published Mon Aug 10, 2015

Description: Author(s): Linhu Li and Shu Chen We study topological properties of phase transition points of topological quantum phase transitions by assigning a topological invariant defined on a closed circle or surface surrounding the phase transition point in the parameter space of momentum and transition driving parameter. By applying our s… [Phys. Rev. B 92, 085118] Published Mon Aug 10, 2015

Description: Author(s): S. Di Napoli, M. A. Barral, P. Roura-Bas, L. O. Manuel, A. M. Llois, and A. A. Aligia By means of ab initio calculations we study the effect of O doping of Au chains containing a nanocontact represented by a Ni atom as a magnetic impurity. In contrast to pure Au chains, we find that with a minimum O doping the 5 d x z , y z states of Au are pushed up, crossing the Fermi level. We also find… [Phys. Rev. B 92, 085120] Published Wed Aug 12, 2015

Description: Author(s): J. P. L. Faye, P. Sahebsara, and D. Sénéchal Motivated by the possibility of superconductivity in doped graphene sheets, we investigate superconducting order in the extended Hubbard model on the two-dimensional graphene lattice using the variational cluster approximation (VCA) and the cellular dynamical mean-field theory (CDMFT) with an exact … [Phys. Rev. B 92, 085121] Published Wed Aug 12, 2015

Description: Author(s): Hong-Hao Tu and Germán Sierra We show that infinite matrix product states (MPSs) constructed from conformal field theories can describe ground states of one-dimensional critical systems with open boundary conditions. To illustrate this, we consider a simple infinite MPS for a spin-1/2 chain and derive an inhomogeneous open Halda… [Phys. Rev. B 92, 041119(R)] Published Wed Jul 29, 2015

Description: Author(s): Nicolai Lang and Hans Peter Büchler Motivated by the question of topological classification in interacting models the authors study an exactly solvable two-leg ladder model of spinless fermions with attractive interactions and find its ground states and correlation functions. They also demonstrate the appearance of topologically protected edge states and derive their braiding properties on a microscopic level. [Phys. Rev. B 92, 041118(R)] Published Wed Jul 29, 2015

Description: Author(s): J. G. Tobin, S.-W. Yu, R. Qiao, W. L. Yang, C. H. Booth, D. K. Shuh, A. M. Duffin, D. Sokaras, D. Nordlund, and T.-C. Weng Using x-ray emission spectroscopy and absorption spectroscopy, it has been possible to directly access the states in the unoccupied conduction bands that are involved with 5 f and 6 d covalency in oxidized uranium. By varying the oxidizing agent, the degree of 5 f covalency can be manipulated and monit… [Phys. Rev. B 92, 045130] Published Wed Jul 29, 2015

Description: Author(s): Robert Peters and Norio Kawakami We demonstrate the existence of metallic spin density waves (SDWs) in the Kondo lattice model on a square lattice for a wide range of parameters by means of real space dynamical mean-field theory. In these SDWs, the spin polarization as well as the charge density depend on the lattice site and are m… [Phys. Rev. B 92, 075103] Published Mon Aug 03, 2015

Description: Author(s): Jennifer Cano, Taylor L. Hughes, and Michael Mulligan A given fractional quantum Hall state may admit multiple, distinct edge phases on its boundary. We explore the implications that multiple edge phases have for the entanglement spectrum and entropy of a given bulk state. We describe the precise manner in which the entanglement spectrum depends upon l… [Phys. Rev. B 92, 075104] Published Mon Aug 03, 2015

Description: Author(s): J. H. Lloyd-Williams, R. J. Needs, and G. J. Conduit We propose a pseudopotential for the electron-electron Coulomb interaction to improve the efficiency of many-body electronic structure calculations. The pseudopotential accurately replicates the scattering properties of the Coulomb interaction, and recovers the analytical solution for two electrons … [Phys. Rev. B 92, 075106] Published Wed Aug 05, 2015

Description: Author(s): Zhao Liu, Abolhassan Vaezi, Kyungmin Lee, and Eun-Ah Kim Recent theoretical insights into the possibility of non-Abelian phases in ν = 2 / 3 fractional quantum Hall states revived the interest in the numerical phase diagram of the problem. We investigate the effect of various kinds of two-body interlayer couplings on the (330) bilayer state and exactly solve … [Phys. Rev. B 92, 081102(R)] Published Wed Aug 05, 2015

Description: Author(s): A. C. Shockley, K. R. Shirer, J. Crocker, A. P. Dioguardi, C. H. Lin, D. M. Nisson, N. apRoberts-Warren, P. Klavins, and N. J. Curro We report detailed Knight-shift measurements of the two indium sites in the heavy-fermion compound CeIrIn 5 as a function of temperature and field orientation. We find that the Knight-shift anomaly is orientation dependent, with a crossover temperature T * that varies by 50% as the field is rotated fr… [Phys. Rev. B 92, 085108] Published Wed Aug 05, 2015

Description: Author(s): A. M. Novello, B. Hildebrand, A. Scarfato, C. Didiot, G. Monney, A. Ubaldini, H. Berger, D. R. Bowler, P. Aebi, and Ch. Renner We present a detailed low-temperature scanning tunneling microscopy (STM) study of the commensurate charge density wave (CDW) in 1 T − TiSe 2 in the presence of single atom defects. We find no significant modification of the CDW lattice in single crystals with native defect concentrations where some bul… [Phys. Rev. B 92, 081101(R)] Published Tue Aug 04, 2015

Description: Author(s): Erik G. C. P. van Loon, Hartmut Hafermann, Alexander I. Lichtenstein, and Mikhail I. Katsnelson We consider the thermodynamic consistency of the charge response function in the (extended) Hubbard model. In dynamical mean-field theory (DMFT), thermodynamic consistency is preserved. We prove that the static, homogeneous DMFT susceptibility is consistent as long as vertex corrections obtained fro… [Phys. Rev. B 92, 085106] Published Tue Aug 04, 2015

Description: Author(s): Sedigh Ghamari, Sung-Sik Lee, and Catherine Kallin We study a system of weakly interacting electrons described by the energy dispersion ξ ( k ) = k x 2 − k y 2 − μ in two dimensions within a renormalization group approach. This energy dispersion exhibits a neck-narrowing Lifshitz transition at the critical chemical potential μ c = 0 where a van Hove singularity dev… [Phys. Rev. B 92, 085112] Published Thu Aug 06, 2015

Description: Author(s): Da Wang, Wan-Sheng Wang, and Qiang-Hua Wang Motivated by the recent discovery of high-temperature antiferromagnet SrRu 2 O 6 [Hiley et al. , Angew. Chem. Int. Ed. 53 , 4423 (2014) ; Tian et al. ,  arXiv:1504.03642 ] and its potential to be the parent of a new superconductor upon doping, we construct a minimal t 2 g -orbital model on a honeycomb lattice… [Phys. Rev. B 92, 075112] Published Fri Aug 07, 2015

Description: Author(s): M. R. Norman Recently, a general formalism was presented for gyrotropic, ferroelectric, and multipolar order in spin-orbit coupled metals induced by spin-spin interactions. Here, I point out that the resulting order parameters are equivalent to expectation values of operators that determine natural circular dich… [Phys. Rev. B 92, 075113] Published Fri Aug 07, 2015

Description: Author(s): Bunpei Hara, Akihisa Koga, and Tomosuke Aono We study transport properties for a quantum dot coupled to normal leads with a pseudogap density of states at zero temperature, using the second-order perturbation theory based on the Keldysh formalism. We clarify that the hybridization function Γ ( ω ) ∝ | ω | r ( 0 ≤ r 〈 1 ) induces the cusp or dip structure … [Phys. Rev. B 92, 081103(R)] Published Thu Aug 06, 2015

Description: Author(s): Olabode M. Sule, Hitesh J. Changlani, Isao Maruyama, and Shinsei Ryu We provide evidence for the mapping of critical spin-1 chains, in particular the SU ( 3 ) symmetric bilinear-biquadratic model with additional interactions, to free boson theories using exact diagonalization and the density-matrix renormalization-group algorithm. Using the correspondence with a conform… [Phys. Rev. B 92, 075128] Published Tue Aug 18, 2015

Description: Author(s): Yong Xu, Peizhe Tang, and Shou-Cheng Zhang Two-dimensional stanene is a promising candidate material for realizing a room-temperature quantum spin Hall (QSH) effect. Monolayer stanene has recently been fabricated by molecular beam epitaxy, but shows metallic features on a Bi 2 Te 3 (111) substrate, which motivates us to study the important influ… [Phys. Rev. B 92, 081112(R)] Published Tue Aug 18, 2015

Description: Author(s): J. Towers, B. P. van Zyl, and W. Kirkby In a recent paper [B. P. van Zyl et al. , Phys. Rev. A 89 , 022503 (2014) ], the average density approximation (ADA) was implemented to develop a parameter-free, nonlocal kinetic energy functional to be used in the orbital-free density functional theory of an inhomogeneous, two-dimensional (2D) Fermi … [Phys. Rev. B 92, 075129] Published Thu Aug 20, 2015

Description: Author(s): Chi-Ken Lu, Dah-Wei Chiou, and Feng-Li Lin We consider integer quantum Hall states and calculate the bulk entanglement spectrum by formulating the correlation matrix in the guiding center representation. Our analytical approach is based on the strategy of redefining the inner product of states in the Hilbert space, via a projection operator,… [Phys. Rev. B 92, 075130] Published Thu Aug 20, 2015

Description: Author(s): G. A. Kapilevich, P. S. Riseborough, A. X. Gray, M. Gulacsi, Tomasz Durakiewicz, and J. L. Smith The compound SmB 6 is a Kondo insulator, where the lowest-energy bulk electronic excitations are spin-excitons. It also has surface states that are subjected to strong spin-orbit coupling. It has been suggested that SmB 6 is also a topological insulator. Here we show that, despite the absence of time-… [Phys. Rev. B 92, 085133] Published Thu Aug 20, 2015

Description: Author(s): Johannes Bauer and Subir Sachdev We study charge-ordered solutions for fermions on a square lattice interacting with dynamic antiferromagnetic fluctuations. Our approach is based on real-space Eliashberg equations, which are solved self-consistently. We first show that the antiferromagnetic fluctuations can induce arc features in t… [Phys. Rev. B 92, 085134] Published Thu Aug 20, 2015

Description: Author(s): Damian Rybicki, Jonas Kohlrautz, Jürgen Haase, Martin Greven, Xudong Zhao, Mun K. Chan, Chelsey J. Dorow, and Michael J. Veit Nuclear magnetic resonance (NMR) experiments on single crystals of HgBa 2 CuO 4 + δ are presented that identify two distinct temperature-dependent spin susceptibilities: One is due to a spin component that is temperature-dependent above the critical temperature for superconductivity ( T c ) and reflects pse… [Phys. Rev. B 92, 081115(R)] Published Mon Aug 24, 2015

Description: Author(s): Shalinee Chikara, Daniel Haskel, Jae-Hoon Sim, Heung-Sik Kim, Cheng-Chien Chen, G. Fabbris, L. S. I. Veiga, N. M. Souza-Neto, J. Terzic, K. Butrouna, G. Cao, Myung Joon Han, and Michel van Veenendaal In a combined experimental and theoretical study, we investigate the properties of Sr 2 Ir 1 − x Rh x O 4 . From the branching ratios of the L -edge isotropic x-ray absorption spectra, we determine that the spin-orbit coupling is remarkably independent of x for both iridium and rhodium sites. DFT + U calculation… [Phys. Rev. B 92, 081114(R)] Published Mon Aug 24, 2015

Description: Author(s): C. Pauly, C. Saunus, M. Liebmann, and M. Morgenstern Using low-temperature scanning tunneling spectroscopy, we probe the Landau levels of the topologically protected state of Sb 2 Te 3 (0001) after in situ cleavage of a single crystal. Landau levels are visible for magnetic fields B ≥ 2 T at energies, which confirm the Dirac type dispersion including the ze… [Phys. Rev. B 92, 085140] Published Mon Aug 24, 2015

Description: Author(s): N. Xu, C. E. Matt, P. Richard, A. van Roekeghem, S. Biermann, X. Shi, S.-F. Wu, H. W. Liu, D. Chen, T. Qian, N. C. Plumb, M. Radović, Hangdong Wang, Qianhui Mao, Jianhua Du, Minghu Fang, J. Mesot, H. Ding, and M. Shi Combining photoemission spectroscopy, Raman spectroscopy, and first-principles calculations, we characterize superconducting TlNi 2 Se 2 as a material with weak electronic Coulomb correlations leading to a bandwidth renormalization of 1.4. We identify a camelback-shaped band, whose energetic position s… [Phys. Rev. B 92, 081116(R)] Published Mon Aug 24, 2015

Description: Author(s): I. Leonov We employ a combination of the ab initio band-structure methods and dynamical mean-field theory to determine the electronic structure and phase stability of paramagnetic FeO at high pressure and temperature. Our results reveal a high-spin to low-spin transition within the B1 crystal structure of FeO… [Phys. Rev. B 92, 085142] Published Mon Aug 24, 2015

Description: Author(s): Elsa Abreu, Siming Wang, Juan Gabriel Ramírez, Mengkun Liu, Jingdi Zhang, Kun Geng, Ivan K. Schuller, and Richard D. Averitt Optical-pump terahertz-probe spectroscopy is used to investigate ultrafast far-infrared conductivity dynamics during the insulator-to-metal transition in vanadium sesquioxide ( V 2 O 3 ) . The resultant conductivity increase occurs on a tens of picosecond time scale, exhibiting a strong dependence on the … [Phys. Rev. B 92, 085130] Published Tue Aug 18, 2015

Description: Author(s): Izak Snyman and Serge Florens We investigate the entanglement properties of a standard circuit-QED setup that consists of a Cooper pair box coupled to a long chain of Josephson junctions. We calculate the static charge polarization at finite distances along the device. Our calculations reveal a deep connection to the Kondo scree… [Phys. Rev. B 92, 085131] Published Tue Aug 18, 2015

Description: Author(s): Doohee Cho, Yong-Heum Cho, Sang-Wook Cheong, Ki-Seok Kim, and Han Woong Yeom We investigate the interplay of the electron-electron and electron-phonon interactions in the electronic structure of an exotic insulating state in the layered dichalcogenide 1 T − TaS 2 , where the charge-density-wave (CDW) order coexists with a Mott correlation gap. Scanning tunneling microscopy and sp… [Phys. Rev. B 92, 085132] Published Tue Aug 18, 2015

Description: Author(s): E. Mun, S. L. Bud'ko, Y. Lee, C. Martin, M. A. Tanatar, R. Prozorov, and P. C. Canfield Heavy fermion systems are useful for studying quantum criticality because the low energy scale associated with their large effective mass can be tuned by nonthermal control parameters. Here, Shubnikov-de Haas oscillations are observed in YbPtBi, a heavy fermion compound with an exceptionally large effective mass for electrons, at a high magnetic field that reveals the shape of the Fermi surface. In the future these observations, when combined with additional data at lower magnetic fields, could provide important information about quantum criticality in these systems. [Phys. Rev. B 92, 085135] Published Thu Aug 20, 2015

Description: Author(s): G. Antonius, S. Poncé, E. Lantagne-Hurtubise, G. Auclair, X. Gonze, and M. Côté The renormalization of the band structure at zero temperature due to electron-phonon coupling is explored in diamond, BN, LiF, and MgO crystals. We implement a dynamical scheme to compute the frequency-dependent self-energy and the resulting quasiparticle electronic structure. Our calculations revea… [Phys. Rev. B 92, 085137] Published Fri Aug 21, 2015

Description: Author(s): TeYu Chien (簡德宇), Xiaobo He, Sung-Kwan Mo, Makoto Hashimoto, Zahid Hussain, Zhi-Xun Shen, and E. W. Plummer The momentum-resolved Eliashberg function (ELF) α 2 F ( ω , k ⇀ ) for the Be ( 0001 ) zone-center surface state was extracted from the high-quality angle-resolved photoemission spectroscopy (ARPES) data at the Fermi energy in the Γ ¯ → M ¯ direction, displaying ten peaks. A comparison of the peaks in the ELF to th… [Phys. Rev. B 92, 075133] Published Fri Aug 21, 2015

Description: Author(s): Daniel Gosálbez-Martínez, Ivo Souza, and David Vanderbilt Using bcc Fe as a playground, the authors investigate the presence of chiral degeneracies in realistic band structures of ferromagnetic materials. They find ubiquitous Weyl points and demonstrate that Chern numbers can be transferred between Fermi sheets by varying the Fermi level or an external parameter such as the magnetization direction. [Phys. Rev. B 92, 085138] Published Fri Aug 21, 2015

Description: Author(s): Matthew T. Fishman and Steven R. White Here we present an efficient and numerically stable procedure for compressing a correlation matrix into a set of local unitary single-particle gates, which leads to a very efficient way of forming the matrix product state (MPS) approximation of a pure fermionic Gaussian state, such as the ground sta… [Phys. Rev. B 92, 075132] Published Fri Aug 21, 2015

Description: Author(s): Alexander Hampel, Christoph Piefke, and Frank Lechermann We study the correlated electronic structure of single-layer iridates based on structurally undistorted Ba 2 IrO 4 . Starting from the first-principles band structure, the interplay between local Coulomb interactions and spin-orbit coupling is investigated by means of rotational-invariant slave-boson me… [Phys. Rev. B 92, 085141] Published Mon Aug 24, 2015

Description: Author(s): Szabolcs Vajna, Balázs Dóra, and R. Moessner The nonequilibrium dynamics beyond the linear response of Weyl semimetals is studied after a sudden switching on of a dc electric field. The resulting current is a nonmonotonic function of time with an initial quick increase in polarization current followed by a power-law decay. Particle-hole creati… [Phys. Rev. B 92, 085122] Published Thu Aug 13, 2015

Description: Author(s): Carlos A. Jiménez-Hoyos and Gustavo E. Scuseria We introduce a mean-field and a perturbative approach, based on clusters, to describe the ground state of fermionic strongly correlated systems. In the cluster mean-field approach, the ground-state wave function is written as a simple tensor product over optimized cluster states. The optimization of… [Phys. Rev. B 92, 085101] Published Mon Aug 03, 2015

Description: Author(s): M. Rösner, E. Şaşıoğlu, C. Friedrich, S. Blügel, and T. O. Wehling We introduce an approach to derive realistic Coulomb interaction terms in freestanding layered materials and vertical heterostructures from ab initio modeling of the corresponding bulk materials. To this end, we establish a combination of calculations within the framework of the constrained random-p… [Phys. Rev. B 92, 085102] Published Mon Aug 03, 2015

Description: Author(s): Laurent Raymond, Alberto D. Verga, and Arnaud Demion We investigate a transition between a two-dimensional topological insulator conduction state, characterized by a conductance G = 2 (in fundamental units e 2 / h ) and a Chern insulator with G = 1 , induced by polarized magnetic impurities. Two kinds of coupling, ferromagnetic and antiferromagnetic, are consi… [Phys. Rev. B 92, 075101] Published Mon Aug 03, 2015

Description: Author(s): Sangram Biswas, Ramya Nagarajan, Suman Sarkar, Kazi Rafsanjani Amin, M. Ciomaga Hatnean, S. Tewari, G. Balakrishnan, and Aveek Bid SmB 6 has been predicted to be a Kondo topological insulator with topologically protected conducting surface states. We have studied quantitatively the electrical transport through surface states in high-quality single crystals of SmB 6 . We observe a large nonlocal surface signal at temperatures lower… [Phys. Rev. B 92, 085103] Published Mon Aug 03, 2015

Description: Author(s): Motoharu Kitatani, Naoto Tsuji, and Hideo Aoki The dynamical mean-field theory (DMFT) combined with the fluctuation exchange (FLEX) method, namely, FLEX+DMFT, is an approach for correlated electron systems to incorporate both local and nonlocal long-range correlations in a self-consistent manner. We formulate FLEX+DMFT in a systematic way starti… [Phys. Rev. B 92, 085104] Published Mon Aug 03, 2015

Description: Author(s): T. Mazet, D. Malterre, M. François, L. Eichenberger, M. Grioni, C. Dallera, and G. Monaco We investigate the composition and temperature (10–450 K) dependence of the Yb valence in YbMn 6 Ge 6 − x Sn x ( x = 0.0 , 3.8, 4.2, 4.4, and 5.5) using resonant inelastic x-ray scattering (RIXS). The observed change in the Yb valence with composition (from υ ∼ 3 for x = 0 to υ ∼ 2.7 for x = 5.5 ) is likely driven by n… [Phys. Rev. B 92, 075105] Published Wed Aug 05, 2015

Description: Author(s): M. A. Rajabpour We derive exact formulas for bipartite von Neumann entanglement entropy after partial projective local measurement in ( 1 + 1 ) -dimensional conformal field theories with periodic and open boundary conditions. After defining the setup we will check numerically the validity of our results in the case of K… [Phys. Rev. B 92, 075108] Published Wed Aug 05, 2015

Description: Author(s): Heung-Sik Kim, Yige Chen, and Hae-Young Kee There have been increasing efforts in realizing topological metallic phases with nontrivial surface states. It was suggested that orthorhombic perovskite iridates are classified as a topological crystalline metal (TCM) with flat surface states protected by lattice symmetries. Here we perform first-p... [Phys. Rev. B 91, 235103] Published Wed Jun 03, 2015

Description: Author(s): N. E. Sluchanko, A. L. Khoroshilov, M. A. Anisimov, A. N. Azarevich, A. V. Bogach, V. V. Glushkov, S. V. Demishev, V. N. Krasnorussky, N. A. Samarin, N. Yu. Shitsevalova, V. B. Filippov, A. V. Levchenko, G. Pristas, S. Gabani, and K. Flachbart The magnetoresistance (MR) Δ ρ / ρ of the cage-glass compound Ho x Lu 1 − x B 12 with various concentrations of magnetic holmium ions ( x ≤ 0.5 ) has been studied in detail concurrently with magnetization M ( T ) and Hall effect investigations on high-quality single crystals at temperatures 1.9–120 K and in magnetic... [Phys. Rev. B 91, 235104] Published Wed Jun 03, 2015

Description: Author(s): Yaroslav A. Kharkov and Oleg P. Sushkov We consider two spin- 1 / 2 fermions in a two-dimensional magnetic system that is close to the O ( 3 ) magnetic quantum critical point (QCP) which separates magnetically ordered and disordered phases. Focusing on the disordered phase in the vicinity of the QCP, we demonstrate that the criticality results ... [Phys. Rev. B 91, 235105] Published Wed Jun 03, 2015

Description: Author(s): C. Lemell, S. Neppl, G. Wachter, K. Tőkési, R. Ernstorfer, P. Feulner, R. Kienberger, and J. Burgdörfer A method is proposed to solve a longstanding problem in photoelectron spectroscopy: the determination of the branching ratio between intrinsic and extrinsic plasmon generation. Attosecond metrology in combination with model simulations allow for a disentanglement of these excitation channels providing novel insight into the many-electron response of metals. [Phys. Rev. B 91, 241101(R)] Published Wed Jun 03, 2015

Description: Author(s): Runan Shang, Hai-Ou Li, Gang Cao, Guodong Yu, Ming Xiao, Tao Tu, Guang-Can Guo, Hongwen Jiang, A. M. Chang, and Guo-Ping Guo We investigate the Kondo effect in a quadruple-quantum-dot device of coupled double quantum dots (DQDs), which simultaneously contain intra-DQD and inter-DQD coupling. A variety of novel behaviors are observed. The differential conductance dI / dV is measured in the upper DQDs as a function of source ... [Phys. Rev. B 91, 245102] Published Tue Jun 02, 2015

Description: Author(s): Emil Prodan A concrete strategy is presented for generating strong topological insulators in d + d ′ dimensions which have quantized physics in d dimensions. Here, d counts the physical and d ′ the virtual dimensions. It consists of seeking d -dimensional representations of operator algebras which are usually define... [Phys. Rev. B 91, 245104] Published Wed Jun 03, 2015

Description: Author(s): Li Lang, Yue-Yu Zhang, Peng Xu, Shiyou Chen, H. J. Xiang, and X. G. Gong Band offsets between different semiconductors are important parameters that determine the electronic transport properties near the interface in the heterostructure devices. The computation of the natural band offset is a well-known challenge. In this paper, we propose a new method, which is called t… [Phys. Rev. B 92, 075102] Published Mon Aug 03, 2015

Description: Author(s): Srinidhi T. Ramamurthy and Taylor L. Hughes Topological semimetals are gapless states of matter which have robust and unique electromagnetic responses and surface states. In this paper, we consider semimetals which have pointlike Fermi surfaces in various spatial dimensions D = 1 , 2 , 3 which naturally occur in the transition between a weak topolo… [Phys. Rev. B 92, 085105] Published Mon Aug 03, 2015

Description: Author(s): Maxim A. Gorlach and Pavel A. Belov We reveal extraordinary electromagnetic properties for a general class of uniaxially polarizable media. Depending on parameters, such metamaterials may have a wide range of nontrivial shapes of isofrequency contours including lemniscate, diamond, and multiply connected curves with connectivity numbe… [Phys. Rev. B 92, 085107] Published Tue Aug 04, 2015

Description: Author(s): Lluís Balcells, Markos Paradinas, Núria Baguès, Neus Domingo, Roberto Moreno, Regina Galceran, Michael Walls, José Santiso, Zorica Konstantinovic, Alberto Pomar, Marie-Jo Casanove, Carmen Ocal, Benjamín Martínez, and Felip Sandiumenge There is increasing evidence supporting the strong potential of twin walls in ferroic materials as distinct, spatially tunable, functional elements in future electronic devices. Here, we report an increase of about one order of magnitude in conductivity and more robust magnetic interactions at (100)… [Phys. Rev. B 92, 075111] Published Fri Aug 07, 2015

Description: Author(s): Xinguo Ren, Noa Marom, Fabio Caruso, Matthias Scheffler, and Patrick Rinke Motivated by the recently developed renormalized second-order perturbation theory for ground-state energy calculations, we propose a second-order screened exchange correction (SOSEX) to the G W self-energy. This correction follows the spirit of the SOSEX correction to the random-phase approximation f… [Phys. Rev. B 92, 081104(R)] Published Fri Aug 07, 2015

Description: Author(s): Takahiro Morimoto, Akira Furusaki, and Naoto Nagaosa The authors describe two theoretical setups that could be used to demonstrate the yet unobserved topological magnetoelectric effect. The first proposal employs the zero-filling quantum Hall effect in thin films under magnetic field. The second setup involves topological insulator thin films doped with two magnetic ions such as Cr and Mn. [Phys. Rev. B 92, 085113] Published Fri Aug 07, 2015

Description: Author(s): Tsuneya Yoshida and Akira Furusaki We study interaction effects on the topological crystalline insulators protected by time-reversal ( T ) and reflection symmetry ( R ) in two and three spatial dimensions. From the stability analysis of the edge states with bosonization, we find that the classification of the two-dimensional symmetry-pro… [Phys. Rev. B 92, 085114] Published Fri Aug 07, 2015

Description: Author(s): Xueda Wen, Po-Yao Chang, and Shinsei Ryu We study the time evolution of the entanglement negativity after a local quantum quench in (1 + 1)-dimensional conformal field theories (CFTs), which we introduce by suddenly joining two initially decoupled CFTs at their end points. We calculate the negativity evolution for both adjacent intervals a… [Phys. Rev. B 92, 075109] Published Thu Aug 06, 2015