Constrained titanohematite formation at BTO/Fe interfaces deposited by RF-sputtering

The usage of heterostructures of ferromagnetic and ferroelectric materials, as a means of achieving magnetoelectric multiferroic coupling, is a widely used approach which has been showing promising results. Along this line of thought, the deposition of BaTiO3 and Fe multilayers on LaAlO3, MgO, Al2O3 and SrTiO3 substrates using RF-magnetron sputtering was carried out to study its viability to produce magnetoelectric heterostructures. It is shown that each substrate constrains the growth of the deposited thin films, even for the same deposition conditions. This is clearly seen through the magnetic properties of the thin film, mainly after performing a 900 °C thermal annealing in air. The thermal annealing results in the creation of iron oxides specific of each one of the substrates where the deposition took place.publishe

Ship-Based Repeat Hydrography: A Strategy for a Sustained Global Program."

ABSTRACT Ship-based hydrography is the only method for obtaining high-quality measurements with high spatial and vertical resolution of a suite of physical, chemical, and biological parameters over the full ocean water column, and in areas of the ocean inaccessible to other platforms. Global hydrographic surveys have been carried out approximately every decade since the 1970s through research programs such as GEOSECS, TTO/SAVE, WOCE / JGOFS, and CLIVAR. It is time to consider how future surveys can build on these foundations to create a coordinated network of sustained ship-based hydrographic sections that will become an integral component of the ocean observing system. This white paper provides scientific justification and guidelines for the development of a regular and coordinated global survey

The Southwest Pacific Ocean circulation and climate experiment (SPICE) : report to CLIVAR SSG

The Southwest Pacific Ocean Circulation and Climate Experiment (SPICE) is an international research program under the auspices of CLIVAR. The key objectives are to understand the Southwest Pacific Ocean circulation and the South Pacific Convergence Zone (SPCZ) dynamics, as well as their influence on regional and basin-scale climate patterns. South Pacific thermocline waters are transported in the westward flowing South Equatorial Current (SEC) toward Australia and Papua-New Guinea. On its way, the SEC encounters the numerous islands and straits of the Southwest Pacific and forms boundary currents and jets that eventually redistribute water to the equator and high latitudes. The transit in the Coral, Solomon, and Tasman Seas is of great importance to the climate system because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate the El Nino-Southern Oscillation, while the southward transports influence the climate and biodiversity in the Tasman Sea. After 7 years of substantial in situ oceanic observational and modeling efforts, our understanding of the region has much improved. We have a refined description of the SPCZ behavior, boundary currents, pathways, and water mass transformation, including the previously undocumented Solomon Sea. The transports are large and vary substantially in a counter-intuitive way, with asymmetries and gating effects that depend on time scales. This paper provides a review of recent advancements and discusses our current knowledge gaps and important emerging research directions

Global perspectives on observing ocean boundary current systems

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Todd, R. E., Chavez, F. P., Clayton, S., Cravatte, S., Goes, M., Greco, M., Ling, X., Sprintall, J., Zilberman, N., V., Archer, M., Aristegui, J., Balmaseda, M., Bane, J. M., Baringer, M. O., Barth, J. A., Beal, L. M., Brandt, P., Calil, P. H. R., Campos, E., Centurioni, L. R., Chidichimo, M. P., Cirano, M., Cronin, M. F., Curchitser, E. N., Davis, R. E., Dengler, M., deYoung, B., Dong, S., Escribano, R., Fassbender, A. J., Fawcett, S. E., Feng, M., Goni, G. J., Gray, A. R., Gutierrez, D., Hebert, D., Hummels, R., Ito, S., Krug, M., Lacan, F., Laurindo, L., Lazar, A., Lee, C. M., Lengaigne, M., Levine, N. M., Middleton, J., Montes, I., Muglia, M., Nagai, T., Palevsky, H., I., Palter, J. B., Phillips, H. E., Piola, A., Plueddemann, A. J., Qiu, B., Rodrigues, R. R., Roughan, M., Rudnick, D. L., Rykaczewski, R. R., Saraceno, M., Seim, H., Sen Gupta, A., Shannon, L., Sloyan, B. M., Sutton, A. J., Thompson, L., van der Plas, A. K., Volkov, D., Wilkin, J., Zhang, D., & Zhang, L. Global perspectives on observing ocean boundary current systems. Frontiers in Marine Science, 6, (2010); 423, doi: 10.3389/fmars.2019.00423.Ocean boundary current systems are key components of the climate system, are home to highly productive ecosystems, and have numerous societal impacts. Establishment of a global network of boundary current observing systems is a critical part of ongoing development of the Global Ocean Observing System. The characteristics of boundary current systems are reviewed, focusing on scientific and societal motivations for sustained observing. Techniques currently used to observe boundary current systems are reviewed, followed by a census of the current state of boundary current observing systems globally. The next steps in the development of boundary current observing systems are considered, leading to several specific recommendations.RT was supported by The Andrew W. Mellon Foundation Endowed Fund for Innovative Research at WHOI. FC was supported by the David and Lucile Packard Foundation. MGo was funded by NSF and NOAA/AOML. XL was funded by China’s National Key Research and Development Projects (2016YFA0601803), the National Natural Science Foundation of China (41490641, 41521091, and U1606402), and the Qingdao National Laboratory for Marine Science and Technology (2017ASKJ01). JS was supported by NOAA’s Global Ocean Monitoring and Observing Program (Award NA15OAR4320071). DZ was partially funded by the Joint Institute for the Study of the Atmosphere and Ocean (JISAO) under NOAA Cooperative Agreement NA15OAR4320063. BS was supported by IMOS and CSIRO’s Decadal Climate Forecasting Project. We gratefully acknowledge the wide range of funding sources from many nations that have enabled the observations and analyses reviewed here

Controls on circulation, cross-shelf exchange, and dense water formation in an Antarctic polynya

Circulation on the Antarctic continental shelf influences cross-shelf exchange, Antarctic Bottom Water formation, and ocean heat flux to floating ice shelves. The physical processes driving the shelf circulation and its seasonal and interannual variability remain poorly understood. We use a unique time series of repeat hydrographic observations from the Adélie Land continental shelf and a box inverse model to explore the relationship between surface forcing, shelf circulation, cross-shelf exchange, and dense water formation. A wind-driven northwestward coastal current, set up by onshore Ekman transport, dominates the summer circulation. During winter, strong buoyancy loss creates dense shelf water. This dense water flows off the shelf, with a compensating on-shelf flow that is an order of magnitude larger in winter than in summer. The results demonstrate the importance of winter buoyancy loss in driving the shelf circulation and cross-shelf exchange, as well as dense water mass formation

Formation rates of Subantarctic mode water and Antarctic intermediate water within the South Pacific

The formation of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW) significantly contributes to the total uptake and storage of anthropogenic gases, such as CO 2 and chlorofluorocarbons (CFCs), within the world's oceans. SAMW and AAIW formation rates in the South Pacific are quantified based on CFC-12 inventories using hydrographic data from WOCE, CLIVAR, and data collected in the austral winter of 2005. This study documents the first wintertime observations of CFC-11 and CFC-12 saturations with respect to the 2005 atmosphere in the formation region of the southeast Pacific for SAMW and AAIW. SAMW is 94% and 95% saturated for CFC-11 and CFC-12, respectively, and AAIW is 60% saturated for both CFC-11 and CFC-12. SAMW is defined from the Subantarctic Front to the equator between potential densities 26.80–27.06 kg m −3, and AAIW is defined from the Polar Front to 20°N between potential densities 27.06–27.40 kg m −3. CFC-12 inventories are 16.0×10 6 moles for SAMW and 8.7×10 6 moles for AAIW, corresponding to formation rates of 7.3±2.1 Sv for SAMW and 5.8±1.7 Sv for AAIW circulating within the South Pacific. Inter-ocean transports of SAMW from the South Pacific to the South Atlantic are estimated to be 4.4±0.6 Sv. Thus, the total formation of SAMW in the South Pacific is approximately 11.7±2.2 Sv. These formation rates represent the average formation rates over the major period of CFC input, from 1970 to 2005. The CFC-12 inventory maps provide direct evidence for two areas of formation of SAMW, one in the southeast Pacific and one in the central Pacific. Furthermore, eddies in the central Pacific containing high CFC concentrations may contribute to SAMW and to a lesser extent AAIW formation. These CFC-derived rates provide a baseline with which to compare past and future formation rates of SAMW and AAIW. ► Formation rates of SAMW, 11.7±2.2 Sv and AAIW, 5.8±1.7 Sv. ► Main areas of SAMW formation is the southeast and central Pacific. ► Main area of AAIW formation is the southeast Pacific. ► SAMW and AAIW formation in South Pacific, major contribution to formation worldwide

Tailoring of YIG film properties via compositional tuning by multi-beam pulsed laser deposition

We report an investigation of the effects of variation of composition on the properties of YIG (yttrium iron garnet) films grown on YAG substrates by multi-beam pulsed laser deposition (PLD)