Active and Passive Acoustic Methods for In-situ Monitoring of the Ocean Status

Recent European strategic plans for the successful monitoring of the status of the ocean push on the development of an integrated observing system able to further link existing instruments and techniques with the aim to complement each other and answer open issues. A more intensive use of acoustic devices could contribute to the knowledge of oceanographic processes exploiting the characteristic of sound to travel in the ocean for a wide area than in the atmosphere. In this context, the installation of passive acoustic instruments, able to listen to ambient noise on fixed or mobile platforms, could contribute to provide information on sound budget and to enhance the monitoring capacity of meteorological phenomena also in the open ocean. Instead, the deployment of active acoustic instruments can be of benefit for monitoring biological activities through the analysis of backscatter data as well as for monitoring ocean waves

Hydrology

In this book, an attempt is made to highlight the recent advances in Hydrology. The several topics examined in this book form the underpinnings of larger-scale considerations, including but not limited to topics such as large-scale hydrologic processes and the evolving field of Critical Zone Hydrology. Computational modeling, data collection, and visualization are additional subjects, among others, examined in the set of topics presented

Surface variability of climate-relevant trace gases (N2O, CO2, CO) in the tropical eastern South Pacific Ocean

Given the climatic relevance of marine-derived trace gases, the investigation of their distribution and emissions from key oceanic regions is a crucial need in our efforts to better understand potential responses of the ocean and the overlying atmosphere to environmental changes such as warming and deoxygenation. Low-oxygen waters connected to coastal upwelling systems and the associated oxygen minimum zones(OMZ) are well-recognized strong sources of several trace gases. Our main goal during the M135-M138 cruises was to assess the distribution of different gases which are relevant for the biogeochemical cycling of carbon and nitrogen in the OMZ off Peru, as well as the spatial and temporal variability of their sea-air fluxes

Challenges for Sustained Observing and Forecasting Systems in the Mediterranean Sea

The Mediterranean community represented in this paper is the result of more than 30 years of EU and nationally funded coordination, which has led to key contributions in science concepts and operational initiatives. Together with the establishment of operational services, the community has coordinated with universities, research centers, research infrastructures and private companies to implement advanced multi-platform and integrated observing and forecasting systems that facilitate the advancement of operational services, scientific achievements and mission-oriented innovation. Thus, the community can respond to societal challenges and stakeholders needs, developing a variety of fit-for-purpose services such as the Copernicus Marine Service. The combination of state-of-the-art observations and forecasting provides new opportunities for downstream services in response to the needs of the heavily populated Mediterranean coastal areas and to climate change. The challenge over the next decade is to sustain ocean observations within the research community, to monitor the variability at small scales, e.g., the mesoscale/submesoscale, to resolve the sub-basin/seasonal and inter-annual variability in the circulation, and thus establish the decadal variability, understand and correct the model-associated biases and to enhance model-data integration and ensemble forecasting for uncertainty estimation. Better knowledge and understanding of the level of Mediterranean variability will enable a subsequent evaluation of the impacts and mitigation of the effect of human activities and climate change on the biodiversity and the ecosystem, which will support environmental assessments and decisions. Further challenges include extending the science-based added-value products into societal relevant downstream services and engaging with communities to build initiatives that will contribute to the 2030 Agenda and more specifically to SDG14 and the UN's Decade of Ocean Science for sustainable development, by this contributing to bridge the science-policy gap. The Mediterranean observing and forecasting capacity was built on the basis of community best practices in monitoring and modeling, and can serve as a basis for the development of an integrated global ocean observing system

Challenges for Sustained Observing and Forecasting Systems in the Mediterranean Sea

The Mediterranean community represented in this paper is the result of more than 30 years of EU and nationally funded coordination, which has led to key contributions in science concepts and operational initiatives. Together with the establishment of operational services, the community has coordinated with universities, research centers, research infrastructures and private companies to implement advanced multi-platform and integrated observing and forecasting systems that facilitate the advancement of operational services, scientific achievements and mission-oriented innovation. Thus, the community can respond to societal challenges and stakeholders needs, developing a variety of fit-for-purpose services such as the Copernicus Marine Service. The combination of state-of-the-art observations and forecasting provides new opportunities for downstream services in response to the needs of the heavily populated Mediterranean coastal areas and to climate change. The challenge over the next decade is to sustain ocean observations within the research community, to monitor the variability at small scales, e.g., the mesoscale/submesoscale, to resolve the sub-basin/seasonal and inter-annual variability in the circulation, and thus establish the decadal variability, understand and correct the model-associated biases and to enhance model-data integration and ensemble forecasting for uncertainty estimation. Better knowledge and understanding of the level of Mediterranean variability will enable a subsequent evaluation of the impacts and mitigation of the effect of human activities and climate change on the biodiversity and the ecosystem, which will support environmental assessments and decisions. Further challenges include extending the science-based added-value products into societal relevant downstream services and engaging with communities to build initiatives that will contribute to the 2030 Agenda and more specifically to SDG14 and the UN's Decade of Ocean Science for sustainable development, by this contributing to bridge the science-policy gap. The Mediterranean observing and forecasting capacity was built on the basis of community best practices in monitoring and modeling, and can serve as a basis for the development of an integrated global ocean observing system

Beach-Dune System Morphodynamics

Coastal dunes are known for their functions in ecological systems in addition to their aesthetic qualities, providing a highly valuable and unique habitat due to their biodiversity of flora and fauna. They also represent the boundary between land and sea, acting as a protective natural barrier against flooding due to storm surges and wave action. Beach–dune systems are highly dynamic features whose evolution is primarily determined by the mutual and complex exchange of sand through hydrodynamic and eolian processes. The sustainable and resilient conservation of beach–dune (eco)systems in a changing climate requires important insights from multidisciplinary studies and approaches. Toward this vision, this Special Issue is dedicated to collecting original scientific contributions based on field observations, laboratory experiments, and/or numerical models

Ocean of sound: underwater gliders observing the oceanic environment

Ocean gliders play an increasingly important role in the Global Ocean Observing System. They are now routinely used to monitor the ocean, along repeated transect lines from the coast to the open ocean, in remote locations and during severe weather events. They offer persistent presence at sea, collecting high-resolution scientific measurements during months- to year-long missions and over thousands of kilometres. The ocean glider com-munity continuously develops new sensors, new navigation capabilities and new usage for underwater gliders, increasing their observation range. This thesis investigates the opportunity offered by addition of passive acoustic monitoring (PAM) capability on ocean gliders and the associated technical challenges. Ocean gliders’ specificities, such as quiet propulsion, low speed and vertical profiling make them highly suitable for PAM applications. Ocean gliders were equipped with PAM systems during 12 missions in different conditions, in polar regions, in open ocean remote lo-cations and along routine coastal transect lines. This thesis reviews the currently avail-able PAM glider solutions, identifies technical challenges and desirable developments and presents pathways to improved scientific PAM glider observations. Intense ocean glider presence in the northwestern Mediterranean basin provided an experimental framework to demonstrate the ability to collect valuable scientific information from PAM glider surveys. Wind speed measurements obtained from glider-borne acoustic recordings, up to 20m s−1, colocated with collection of oceanographic profiles, can improve air-sea interaction studies. Sperm whale acoustic activity detected on PAM glider recordings provides information on population distribution and behaviour along the glider tracks. Wide addition of PAM systems on the ocean glider fleet would benefit for its global time and space coverage, enabling long-term observations in key areas, critical for conservation, monitoring of anthropogenic pressure and assessment of ecosystems health