Search

A Correction to this paper has been published: https://doi.org/10.1038/s41467-021-22318-6 [ABSTRACT FROM AUTHOR]

Mediterranean Sea eddies are often generated in fixed geographical locations linked to either bathymetric fluctuations, coastline changes, instabilities around islands, or orographic wind forcing. Because of that, the mean circulation exhibits features with the same special scales as the mesoscale field. We provide here a first comparison of eddies detected and tracked using two altimetry products, the Sea Level Anomaly (SLA) and the Absolute Dynamic Topography (ADT), from 2000 to 2015. We showed that more individual eddies and trajectories are detected in the SLA data than in the ADT, having larger radius but lower Eddy Kinetic Energy. The spatial distribution of the mesoscale activity is different between the two data sets: the ADT-detected eddies closely follow the Mean Dynamic Topography (MDT) patterns which include the mean eddy generation sites whereas the SLA-detected eddies show more spatial homogeneity. The larger eddies are generally well detected in both the ADT or the SLA fields, but the numerous smaller and coastal eddies detected in the SLA fields have a tendency to mismatch the ADT detected eddies. Only 20–30% of eddies are detected exclusively in the SLA or the ADT product (i.e. have no collocation in the other field), whereas to 65–80% of the eddies are detected both in the SLA and the ADT fields. The Ierapetra Eddy is a typical example of the limitation of the SLA-detected eddies, as this orographically controlled feature is present in the MDT and thus leads to an artificial cyclonic eddy in the SLA field that shifts around its most frequent position. This study recommends the use of ADT fields for the detection of mesoscale structures in the Mediterranean Sea where the mean circulation and these mesoscale features have the same spatial scale and intensity, and similarly for any other ocean regions where the MDT contains mesoscale patterns. Yet the ADT fields depend on the accuracy of the MDT, and the altimeter-based SLA fields may be preferable in specific locations where the MDT is not reliable. [ABSTRACT FROM AUTHOR]

The elevations of water surfaces hold important information on the earth's oceans and land surface waters. Ocean sea surface height is related to the internal change of the ocean's density and mass associated with ocean circulation and its response to climate change. The flow rates of rivers and volume changes of lakes are crucial to freshwater supplies and the hazards of floods and drought resulting from extreme weather and climate events. The Surface Water and Ocean Topography (SWOT) Mission is a new satellite using advanced radar technology to make headway in observing the variability of the elevation of water surfaces globally, providing fundamentally new information previously not available to the study of earth's waters. Here, we provide the first results of SWOT over oceans, rivers, and lakes. We demonstrate the potential of the mission to address science questions in oceanography and hydrology. Plain Language Summary: Earth is a water planet. The vast amount of ocean water has stored most of the heat released to the atmosphere since the Industrial Revolution through burning fossil fuels. Climate change is thus moderated by the ocean. Over land the freshwater in lakes, rivers, and reservoirs, a critical natural resource, is affected by the warming climate and direct human modifications. Processes of oceanic uptake of heat and carbon from the atmosphere and cycling of freshwater on land take place at spatial scales too small to have been adequately quantified from space. A new satellite, the Surface Water and Ocean Topography (SWOT) mission, was launched in December 2022. Using advanced radar technology, SWOT provides unprecedented global observations for understanding the ocean's role in climate change and how freshwater resources respond to human influence. SWOT observations near coasts will also advance understanding of how rising sea levels impact those coasts. Key Points: The first space observations of submesoscale ocean surface topography for understanding ocean's role in heat uptake from the atmosphereThe first space observations of the change of water storage of lakes and flow rates of rivers for understanding the freshwater cycleThe first space observations of the details of the change of coastal water levels to assess the impact of local sea level rise [ABSTRACT FROM AUTHOR]

Technological advances in the recent satellite altimeter missions of Jason-2, Saral/AltiKa and Cryosat-2 have improved their signal-to-noise, allowing us to observe finer-scale ocean processes with along-track data. Here, we analyse the noise levels and observable ocean scales in the northwest Mediterranean Sea, using spectral analyses of along-track sea surface height from the three missions. Jason-2 has a higher mean noise level with strong seasonal variations, with higher noise in winter due to the rougher sea-state. Saral/AltiKa has the lowest noise, again with strong seasonal variations. Cryosat-2 is in SAR mode in the Mediterranean Sea but with lower resolution ocean corrections; its statistical noise level is moderate with little seasonal variation. These noise levels impact on the ocean scales we can observe. In winter, when the mixed layers are deepest and the sub-mesoscale is energetic, all of the altimeter missions can observe wavelengths down to 40-50 km (individual feature diameters of 20-25 km). In summer when the sub-mesoscales are weaker, Saral can detect ocean scales down to 35 km wavelength, whereas the higher noise from Jason-2 and Cryosat-2 blocks the observation of scales less than 50-55 km wavelength. This statistical analysis is completed by individual case studies, where filtered along-track altimeter data are compared with collocated glider and HF radar data. The glider comparisons work well for larger ocean structures, but observation of the smaller, rapidly moving dynamics are difficult to collocate in space and time (gliders cover 200 km in a few days, altimetry in 30 secs). HF radar surface currents at Toulon measure the meandering Northern Current, and their good temporal sampling shows promising results in comparison to collocated Saral altimetric currents. Techniques to separate the geostrophic component from the wind-driven ageostrophic flow need further development in this coastal band. [ABSTRACT FROM AUTHOR]

We present a new gridded sea surface height and current dataset produced by combining observations from nadir altimeters and drifting buoys. This product is based on a multiscale and multivariate mapping approach that offers the possibility to improve the physical content of gridded products by combining the data from various platforms and resolving a broader spectrum of ocean surface dynamic than in the current operational mapping system. The dataset covers the entire global ocean and spans from 1 July 2016 to 30 June 2020. The multiscale approach decomposes the observed signal into different physical contributions. In the present study, we simultaneously estimate the mesoscale ocean circulations as well as part of the equatorial wave dynamics (e.g. tropical instability and Poincaré waves). The multivariate approach is able to exploit the geostrophic signature resulting from the synergy of altimetry and drifter observations. Sea-level observations in Arctic leads are also used in the merging to improve the surface circulation in this poorly mapped region. A quality assessment of this new product is proposed with regard to an operational product distributed in the Copernicus Marine Service. We show that the multiscale and multivariate mapping approach offers promising perspectives for reconstructing the ocean surface circulation: observations of leads contribute to improvement of the coverage in delivering gap-free maps in the Arctic and observations of drifters help to refine the mapping in regions of intense dynamics where the temporal sampling must be accurate enough to properly map the rapid mesoscale dynamics. Overall, the geostrophic circulation is better mapped in the new product, with mapping errors significantly reduced in regions of high variability and in the equatorial band. The resolved scales of this new product are therefore between 5 % and 10 % finer than the Copernicus product (https://doi.org/10.48670/moi-00148 , Pujol et al., 2022b). [ABSTRACT FROM AUTHOR]

This paper presents the new global Mesoscale Eddy Trajectory Atlases (META3.1exp DT all-satellites, 10.24400/527896/a01-2021.001, Pegliasco et al., 2021a; and META3.1exp DT two-satellites, 10.24400/527896/a01-2021.002, Pegliasco et al., 2021b), composed of eddy identifications and trajectories produced with altimetric maps. The detection method used is inherited from the py-eddy-tracker (PET) algorithm developed by Mason et al. (2014), and is optimized to efficiently manage large datasets, and thus long time series. These products are an improvement on the earlier META2.0 product, which was produced by SSALTO/DUACS and distributed by AVISO + (https://aviso.altimetry.fr , last access: 8 March 2022) with support from CNES, in collaboration with Oregon State University and support from NASA, and based on the Chelton et al. (2011) code. META3.1exp provides supplementary eddy information, such as eddy shapes, eddy edges, maximum speed contours, and mean eddy speed profiles from the center to the periphery. The tracking algorithm is based on overlapping contours, includes virtual observations, and acts as a filter with respect to the shortest trajectories. The absolute dynamic topography (ADT) field is now used for eddy detection, instead of the previous sea level anomaly (SLA) maps, in order to better represent the dynamics in the more energetic oceanic regions and in the vicinity of coasts and islands. To evaluate the impact of the changes from META2.0 to META3.1exp, a comparison methodology has been applied. The similarity coefficient (SC) is based on the ratio of the eddy overlaps to their cumulative area, and allows for extensive comparison of the different datasets in terms of geographic distribution, statistics on the main physical characteristics, changes in the lifetimes of the trajectories, etc. After evaluating the impact of each change separately, we conclude that the major differences between META3.1exp and META2.0 are due to the change in the detection algorithm. META3.1exp contains smaller eddies and trajectories lasting at least 10 d; these were not available in the META2.0 product. Nevertheless, 55 % of the structures in META2.0 are similar to META3.1exp, thereby ensuring continuity between the two products and their physical characteristics. Geographically, the eddy distributions differ mainly in the strong current regions, where the mean dynamic topography (MDT) gradients are sharp. The additional information on the eddy contours allows for more accurate collocation of mesoscale structures with data from other sources, and so META3.1exp is recommended for multi-disciplinary application. [ABSTRACT FROM AUTHOR]

Adding azimuth diversity to InSAR - for example, with squinted SAR beams - vectors of ocean surface current and wind are measured for each single pass ([13]; [11]), exploring new physical processes including fronts, waves, and submesoscales ([14]; [23]). For both coastal and global scales, the joint measurements of wind, waves, and currents open up great opportunities for science and applications linked to ocean-atmosphere coupling and feedbacks, including the ocean energy cycle, from the wind work to the energy cascade in the ocean circulation. The additional measurement of ocean wave spectra should lead to a better understanding of the relation between currents and waves (e.g., [1]) and their impact on extreme sea states (e.g., [10]) and upper-ocean turbulence ([9], [23]). The processing of existing satellite Doppler radar data to a usable quality level to produce single-component current estimates for dissemination and exploitation by the wider scientific community, including existing I Envisat i , Sentinel-1, and Radarsat data;. [Extracted from the article]

In situ measurements of sea surface temperature (SST), salinity (SSS), Total Alkalinity (A T) and Total Carbon (C T) were obtained during austral summer (mid-February to mid-March) from 2005 to 2019 in the Southern Ocean (SO), along a transect between Hobart, Tasmania and Dumont d'Urville French Antarctic Station. The studied transect is divided in four regions from North to South: the Subtropical Zone (STZ), the Subantarctic Region (SAR), the Antarctic Region (AAR) and the Coastal Antarctic Zone (CAZ). Latitudinal distribution of measured SST, SSS, A T , C T as well as calculated pH, CO 2 parameters (seawater fugacity of CO 2 (fCO 2sw), difference between seawater and atmospheric fCO 2 (ΔfCO 2), CO 2 flux (FCO 2)) and satellite-derived Chlorophyll a (Chl-a) are discussed. We show that the variability of physical and carbonate parameters in the STZ and north of the SAR are related to the mesoscale activity. In the CAZ, the freshwater inputs from sea-ice melting strongly impact the variability of all parameters. The comparison between physical and carbonate parameters highlights that A T and C T are directly related to the latitudinal variability of SST and SSS. Study of the CO 2 parameters shows that the transect is a sink of CO 2 during February and March, with a mean FCO 2 of −4.0 ± 2.8 mmol m−2 d−1. The most negative values of FCO 2 are found in the STZ and SAR north of 50°S and in the AAR south of 62°S, where biological activity is high. New simple empirical relationships are developed for A T from SST and SSS and for C T using SST, SSS and atmospheric fCO 2 (fCO 2atm) for the austral summer in the studied area. Using high resolution SSS and SST from the SURVOSTRAL program, trends of A T and C T are determined in the SAR and the AAR from 2005 to 2019. SST, SSS and A T increase over this period in the SAR, which might be explained by the southward migration of the Subtropical Front. In the AAR, no clear trend is detected. C T increases by 1.0 ± 0.2 and 0.8 ± 0.3 μmol kg−1 yr−1 in the SAR and AAR respectively. The trend in the AAR is attributed to the increase in anthropogenic CO 2 emissions in the atmosphere while, in the SAR, hydrographic changes also contribute to the increase. Using the coefficient associated with fCO 2atm in the equation of C T , we estimate the impact of atmospheric CO 2 increase on C T at 1.18 ± 0.14 μmol kg−1 yr−1 and 1.07 ± 0.13 μmol kg−1 yr−1 in the SAR and AAR respectively. Decreases in pH are observed in both regions (−0.0018 ± 0.0001 and −0.0026 ± 0.0003 yr−1 in the SAR and AAR respectively), indicating the sensitivity of surface waters in the area towards the development of ocean acidification processes under rising anthropogenic emissions. • Latitudinal and temporal variability of physical and carbonate parameters are studied south of Tasmania. • Physical and carbonate parameters are impacted by mesoscale activity in the STZ and north of SAR. • The region is a sink of CO 2 during summer with a mean CO2 flux of −4.0 ± 2.8 mmol m−2 d−1. • New empirical relationships for A T and C T during austral summer are determined. • The increase in C T and decrease in pH linked to rising anthropogenic emissions. [ABSTRACT FROM AUTHOR]

Purpose: Communication partner training is a recommended intervention for partners of people with acquired brain injury. In this paper we explore the past, present, and future of communication partner training (CPT) based on our 2023 Speech Pathology Australia national conference address., Method: We focus on our research team's contributions, and highlight research knowledge across stroke, traumatic brain injury (TBI), and dementia. This work is anchored in the voice of people with communication disability. One partner in the CPT journey, Rosey Morrow, co-authors this paper., Result: The CPT evidence base for acquired neurological conditions is growing, including in the areas of technology, co-design, and translation. However, knowledge and implementation gaps remain., Conclusion: The future of CPT will require us to harness co-design and technology, whilst meeting the implementation challenges of complex systems to enable communication for all.

Background: Acquired brain injuries (ABIs), such as stroke and traumatic brain injury, commonly cause cognitive-communication disorders, in which underlying cognitive difficulties also impair communication. As communication is an exchange with others, close others such as family and friends also experience the impact of cognitive-communication impairment. It is therefore an internationally recommended best practice for speech-language pathologists to provide communication support to both people with ABI and the people who communicate with them. Current research also identifies a need for neurorehabilitation professionals to support digital communication, such as social media use, after ABI. However, with >135 million people worldwide affected by ABI, alternate and supplementary service delivery models are needed to meet these communication needs. The "Social Brain Toolkit" is a novel suite of 3 interventions to deliver communication rehabilitation via the internet. However, digital health implementation is complex, and minimal guidance exists for ABI., Objective: This study aimed to support the implementation of the Social Brain Toolkit by coproducing implementation knowledge with people with ABI, people who communicate with people with ABI, clinicians, and leaders in digital health implementation., Methods: A maximum variation sample (N=35) of individuals with living experience of ABI, close others, clinicians, and digital health implementation leaders participated in an explanatory sequential mixed methods design. Stakeholders quantitatively prioritized 4 of the 7 theoretical domains of the Nonadoption, Abandonment, Scale-up, Spread, and Sustainability (NASSS) framework as being the most important for Social Brain Toolkit implementation. Qualitative interview and focus group data collection focused on these 4 domains. Data were deductively analyzed against the NASSS framework with stakeholder coauthors to determine implementation considerations and strategies. A collaborative autoethnography of the research was conducted. Interrelationships between considerations and strategies were identified through a post hoc network analysis., Results: Across the 4 prioritized domains of "condition," "technology," "value proposition," and "adopters," 48 digital health implementation considerations and 52 tailored developer and clinician implementation strategies were generated. Benefits and challenges of coproduction were identified. The post hoc network analysis revealed 172 unique relationships between the identified implementation considerations and strategies, with user and persona testing and responsive design identified as the potentially most impactful strategies., Conclusions: People with ABI, close others, clinicians, and digital health leaders coproduced new knowledge of digital health implementation considerations for adults with ABI and the people who communicate with them, as well as tailored implementation strategies. Complexity-informed network analyses offered a data-driven method to identify the 2 most potentially impactful strategies. Although the study was limited by a focus on 4 NASSS domains and the underrepresentation of certain demographics, the wealth of actionable implementation knowledge produced supports future coproduction of implementation research with mutually beneficial outcomes for stakeholders and researchers., International Registered Report Identifier (irrid): RR2-10.2196/35080., (©Melissa Miao, Rosemary Morrow, Alexander Salomon, Ben Mcculloch, Jean-Christophe Evain, Meg Rebecca Wright, Marie Therese Murphy, Monica Welsh, Liz Williams, Emma Power, Rachael Rietdijk, Deborah Debono, Melissa Brunner, Leanne Togher. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 19.09.2023.)

Despite playing a major role in global ocean heat storage, the Southern Ocean remains the most sparsely measured region of the global ocean. Here, a unique 25-year temperature time-series of the upper 800 m, repeated several times a year across the Southern Ocean, allows us to document the long-term change within water-masses and how it compares to the interannual variability. Three regions stand out as having strong trends that dominate over interannual variability: warming of the subantarctic waters (0.29 ± 0.09 °C per decade); cooling of the near-surface subpolar waters (-0.07 ± 0.04 °C per decade); and warming of the subsurface subpolar deep waters (0.04 ± 0.01 °C per decade). Although this subsurface warming of subpolar deep waters is small, it is the most robust long-term trend of our section, being in a region with weak interannual variability. This robust warming is associated with a large shoaling of the maximum temperature core in the subpolar deep water (39 ± 09 m per decade), which has been significantly underestimated by a factor of 3 to 10 in past studies. We find temperature changes of comparable magnitude to those reported in Amundsen-Bellingshausen Seas, which calls for a reconsideration of current ocean changes with important consequences for our understanding of future Antarctic ice-sheet mass loss.