Seismic and Tsunami hazard operational networks
Deep sea observatories also have the potential to play a key role in the assessment and monitoring of geo-hazards, as many of Earth’s most seismogenic zones and most active volcanoes are located along continental margins plate boundaries like South Europe. Continuous measurements are required with the ability to react quickly to episodic events, such as earthquakes and volcanic eruptions.
For estimate earthquake parameters and forecast the expected height of the oncoming water wave, computer aided tsunami generation models are used. In all areas threatened by tsunami hazards, deep sea observatories developed within ESONET will be equipped with seismometers and high precision, low frequency pressure sensors. Each of these ESONET nodes will represent the base for the implementation of a tsunami early warning system covering the Eastern Atlantic and Mediterranean areas.
Deep sea observatories need a real-time communication to on-shore, allowing the integration of their data in the already existing land-based seismic networks. Awaited result is a better understanding of plate-tectonic margin behaviour and of important seismogenic zones located at seas around Europe. ESONET NoE will benefit from already established links with organizations able to manage data and waveforms of terrestrial networks (like ORFEUS and EMSC) through the relationship with other approved EC projects [e.g. NERIES] in which some of the ESONET partners are involved. In relation to other geo-hazards like tsunamis, the actions of ESONET NoE will be conducted in coordination with UNESCO-IOC, following in particular the recommendations of the “Intergovernmental Coordination Group for the Tsunami Early Warning System in the North Eastern Atlantic, the Mediterranean and Connected Seas (ICG/NEAMTWS)” launched at its 1st session held in Rome (November, 2005).
Historical seismic map during last 15 years, indicating at sea tsunami-genic sources in the area defined by the group of North Eastern Atlantic, the Mediterranean and Connected Seas (ICG/NEAMTWS). Courtesy of EMSC.
Oceanography networks (water column)
Integrated operational monitoring and forecasting systems, such as the MERSEA and MyOcean systems, are able to simulate and anticipate ocean conditions. The operational monitoring and forecasting of the ocean physics, bio-geochemistry and, to a certain extent, ecosystem, is being completed within 2-3 years (objective of FP6 –MERSEA IP and FP7-MyOcean projects); Satellite Remote sensing and insitu Lagrangian data provide most of the necessary assimilation inputs to the models but there is a need of Eulerian data.
Indeed, the development of the algorithms for the models, the checking of these models during their development and their validation when operated (especially when forecasting is aimed at) all require time series. In-situ quantities in critical or representative locations need to be collected in a mode that delivers temporal variability on scales of hours to months.
ESONET NoE will provide data on key parameters from the subsurface down to the seafloor at representative locations and transmit them in real time to shore. The strategies of deployment, data sampling, technological development, standardisation and data management will be integrated with projects dealing with the spatial and near surface time series. The contribution of ESONET will come through GMES for several key parameters of the water column. During the next 4 years, the target of GMES is clearly to prepare an operational phase in ocean physical oceanography. ESONET will contribute to “Initial Operational Phase of GMES Marine Core Services” planned for 2008 as well as a regional policy on the Downstream Services. ESONET NoE regional development will take into account the geographical policies of GOOS (Global Ocean Observing System) regional task teams: Arctic, North-West Atlantic shelf NOOS, Mediterranean MedGOOS (reference projects MFSTEP, MOON), Iberia-Biscay-Ireland Shelf IBI-ROOS and Black SeaGOOS.
Time series observatories occupy an indispensable niche in the vast temporal and spatial sampling that is required to monitor and forecast the ocean properly. They are essential to model validation. Progress in ocean model and assessment of system performance depends on rigorous validation against in situ data. For instance the validation of climate scenarios models is often made by considering their ability to reproduce past evolutions, where comprehensive data sets are the only objective reference. In the case of model development, in situ observations provide the necessary data for quantifying ocean processes and guide the tuning of their parametric representation (e.g. mixed layer depth, deep water formation, position of fronts, warm water pool, eddy kinetic energy, mixing, etc.). In the context of operational models, it is valuable either to estimate the misfits between model output and data or to validate forecast skills by comparison of a previous forecast with data effectively collected at the target date.
The ESONET system can provide data in representative locations that delivers the temporal variability on scales of days to months, for:
- providing data on changes, processes, and events unobservable from satellites (like biogeochemical quantities),
- referencing, calibrating, validating satellite products (e.g. chlorophyll),
- estimating and tuning model parameters and process representations (e.g. primary production),
- validating assimilation and forecasting products (ecosystem changes),
- establishing meaningful statistics (high resolution spectra, extreme events, means, variance and covariance).
Time series observatories from the ESONET network offer the advantage of relaxing the stringent constraints of power and data transmission limitations of autonomous surface moorings; they open the perspective of adaptive sampling strategies (burst sampling), high resolution measurements, and multi-parameter observations.
Monitoring of the ocean environment requires not only physical but also ecosystem models. Significant advances have been made in recent years in understanding and modelling the complex processes in ecosystems, ranging from the bio-geochemical processes governing the global carbon cycle (uptake, sequestration, and release) and other gas exchanges, to the coastal ecosystems describing water quality, primary production or algal blooms. The performance of ecosystem models is strongly predicated on the realism of the underlying physics, which in turn depend on good observations.
Well-managed seascapes are the basis of sustainable development and human security. They are critical to address underlying causes of biodiversity loss.
Ecosystem management requires a good knowledge of the structure and function of the communities of organisms inhabiting the pelagic and benthic environments of the deep ocean extending from the edge of the continental shelf to the depths of the deepest trenches. The paucity of sampling and monitoring of this vast area, combined with the increasing demands on open ocean resources, require extensive study of this domain. Deep sea observatories are powerful instruments to approach some critical points:
- spatial and temporal variability in the deep ocean of organisms,
- seasonally and interanually variability of food supply,
- shifts in populations of megafauna,
- description of unknown species of organisms.
They will contribute to resolve questions essential to deep ecosystem management, for instance:
- What processes produce/maintain diversity in deep sea communities?
- What are the vertical and lateral movements of deep sea animals?
- What are the temporal and spatial influences of natural perturbations on deep sea communities?
- How do anthropogenic inputs influence deep sea communities?
- What processes influence the formation, deposition, dissolution, or venting of gas hydrate deposits, and how do gas hydrate dynamics affect the subsea floor biosphere, deep communities or climate system?