Marine Heat Waves, MHW, persistent and anomalously warm events, are known to have significant impacts on biological systems, from shifts in species ranges to biodiversity losses, as well as impacts on ecosystem services and human ocean-based economic activities (e.g., aquaculture and seafood industries). Their detection, attribution and impact are essential if we want to predict changes in ocean health.
The project “deteCtion and threAts of maRinE Heat waves – CAREHeat”, funded by ESA in the framework of the Ocean Health initiative, aims at improving the current MHW detection and characterization methodology, as well as advancing the understanding of the physical processes involved, and the corresponding ecological and biogeochemical changes.
This will be archived - leveraging on the added value of Earth Observation experimental 4D products, using a multi-disciplinary approach combining the novel MHW products, together with satellite-based observations of Ocean Colour (OC), BGC-Argo in situ optical and biogeochemical data and CMEMS biogeochemical model data - developing the following main tasks:
1 Provide a detail assessment of the major gaps in scientific knowledge, existing products and tools in MHW detection and impact assessment; Define technical and scientific requirements, as well as datasets, that will drive CAREHeat methodological development and impact assessment on ecosystems;
2 Develop a novel MHW detection algorithm from space-based SST observations that will optimize existing methodologies and review the today adopted criteria such as minimum duration thresholds of MHW and reference climatology; Investigate the impact of SST trends and prominent climate modes (e.g., ENSO) on MHW detection, and evaluate the role of diurnal warming events in the MHW characteristics;
3 Test and assess a 4D MHW reconstruction algorithm (4D temperature reconstruction and subsurface MHW detection) based on machine learning techniques, on specific test sites; Scaling up the new MHW4D product to generate a global EO experimental dataset covering at least a 10-year recent period;
4 Develop and validate a MHW Global Atlas based on the novel MHW detection methodology and characterize each event in terms of location, duration, intensity and rate of evolution, and as Moderate, Strong, Severe, or Extreme; Complement the Atlas with ancillary meteorological, oceanic geophysical and biological information;
5 Exploit the newly obtained MHW Atlas and MHW4D products to characterize drivers and precursors of MHW; Assess how MHW impact on marine biodiversity (from primary producers to apex predators) and biogeochemistry (dissolved oxygen levels, acidification) from the surface down to the ocean interior, using a multiplatform approach based on Ocean Colour satellite observations, BGC-Argo float measurements and biogeochemical modelling; Identify Compound Events, co-occurring climate and biogeochemical anomaly conditions that are associated with extremely low productivity and low biomass conditions;
6 Assess the impact of new MHW products on the management of key ocean-based human services: fisheries (tunas), aquaculture (sea breams and sugar kelps), and marine protected areas (corals, sea urchins and sea birds); Use of population models and biological observations to assess organism distribution, fertility, mortality, nesting and restoring after MHW events;
These will contribute to the development of a Scientific Agenda and Roadmap and to the establishment of a coordinated European research on Ocean Health and develop synergies with policy makers, NGOs, environmental protection agencies, private companies and the projects belonging to the ESA Ocean Science Cluster. Here, we will present the preliminary results, an overview of the stakeholders engaged, the planned activities and strategies that will be adopted for the scientific development of algorithms, impact assessment of MHW on marine ecosystems, User’s impact assessment, and outreach.