A workshop on ocean dispersion modelling

This project builds on the ongoing technical exchanges and cooperation between Météo-France International (MFI) and SODEXAM, Côte d’Ivoire’s national meteorological service. Within this framework, the Calypso Science team had the opportunity of delivering a five-day workshop on oceanic dispersion modelling to the SODEXAM team in Abidjan last month. The training focused on two key operational applications: search and rescue (SAR) operations at sea and marine pollution response (oil spills).

Supporting national maritime safety

We worked with the team at SODEXAM, Côte d’Ivoire's national meteorological service, to strengthen their capacity to address maritime risks along their coastline. This initiative came together through a collaborative effort between MeteoFrance International, Calypso Science, and WeathernCo, bringing together expertise in high-resolution hydrodynamic, wave and atmospheric modelling and oceanic dispersion modelling systems.

The workshop focused on the use of OpenDrift, an open-source, Python-based oceanic dispersion modelling system developed by the Norwegian Meteorological Institute. OpenDrift is used operationally for maritime emergency response across Norway and has become widely adopted by research teams worldwide studying oceanic transport and dispersion of pollutants such as oil, plastic, chemical, debris, fish larvae and water masses, with numerous peer-reviewed publications demonstrating its capabilities.

We'd like to acknowledge the Norwegian Meteorological Institute for making Opendrift freely available and for their excellent community support. Their commitment to open-source development made this knowledge transfer possible.

What we covered

The workshop began with foundational concepts in Lagrangian dispersion modelling before exploring the wide range of input data that Opendrift can work with—from ocean current models like MERCATOR, SCHISM, and ROMS, wave models like SWAN, WW3, to atmospheric models including ERA5, ECMWF, GFS, ARPEGE, AROME, ICON, and WRF custom domains. We examined how different forcing data affects prediction accuracy and reliability.

We then focused on two specialized modules: the oil spill module, built on theoretical and empirical guidance from NOAA, and the SAR module developed from a database of windage characteristics of numerous sea objects (person-in-water, raft, boat etc..) developed by the US Coast Guard. The practical component included case studies specific to Côte d’Ivoire's coastal waters and inland areas, for which we implemented a high-resolution SCHISM hydrodynamic domain to be used in combination with the high-resolution WRF wind models. We used post-processing and data visualization tools developed at Calypso Science to make the model outputs easier to interpret and apply operationally (see animation).

Looking ahead

The week spent working with the SODEXAM team was very rewarding. Watching the tools come together in their operational context and knowing these dispersion modelling capabilities are now part of their maritime emergency response toolkit—that's what makes collaborative projects like this meaningful.

Calypso Science continues to support SODEXAM through ongoing work to enhance their wave and hydrodynamic forecasting capabilities, ensuring these align with their existing high-resolution wind forecast data for both routine operations and emergency response situations. We're also available for continued support in oceanic dispersion modelling as they continue developing their expertise.

Interested in similar training ?

We'd be pleased to run similar workshops for other meteorological services or agencies looking to develop capabilities in oceanic dispersion modelling. If your organization could benefit from training in oil spill response, SAR operations, or other maritime risk applications.

Please get in touch. We're here to help build capacity where it's needed.

Ocean modelling often means long days behind a screen, refining simulations and crunching data collected by others. But when an opportunity arises to get out in the field and deploy real sensors, we jump at it!

A few years ago, Aqualink provided a Spotter wave buoy with integrated temperature sensors to be deployed at Jackson Reef, just offshore from Raglan (New Zealand). This buoy is part of Aqualink’s global initiative to monitor water temperatures and reef health. For us, it was a win-win: real-time data on waves and temperature meant:

• Improved water safety (e.g. bar crossings),
• Better validation for our wave models,
• And yes… an early surf report, with a geeky breakdown of every Southern Ocean swell rolling into NZ — the first landfall on their journey across the Pacific.

The deployment was a collaborative effort, with mooring hardware sourced from Defence Science and Technology, the anchor weight provided by fellow Raglan oceanographer Brett Beamsley, and the vessel and crew generously provided by the Raglan Coastguards — facilitated by Dave Johnson, Oceanum colleague and active Raglan Coastguard himself. We launched well after dark, after the Coastguard vessel towed a ship back to port, seizing a rare calm West Coast weather window. 

📡 The live wave data from Raglan is now available on SeaScope Aotearoa – our open-access ocean observation portal, where you can check both observations and predictions on the same graph. 

SeaScope Aotearoa is led by Calypso Science with support from OCEANUM.IO’s Datamesh integrates a wide range of open-source and institutional datasets measured by wave buoys, tide gauges, wind stations, ocean drifters, webcams, and more, into a single platform. Observational data includes contributions from projects such as the MOANA Project, the ARGO network, and various regional council monitoring programmes.

🔍 We’re continuously looking to improve and expand the platform:

 → If you have ocean datasets from around Aotearoa that you would like to share and display, we'd love to connect.
 → Want a SeaScope-style platform for your region or project? We’re happy to collaborate.
 → Ideas or feedback on the app and dataviz? We’re listening.

In the summers of 2024 and 2025, the New Zealand Department of Conservation conducted blue whale surveys (SAPPHIRE project) off the west coast. A concerning finding was very few sightings in 2024, while more were observed in 2025.

We are oceanographers and not whale experts, so we decided to look at physical differences between the two periods. Our speculation actually started because, as kite surfers, we had been complaining about the lack of good sessions during the summer of 2024…

Using the ERA5 from OCEANUM.IO, we rapidly computed the wind speed anomalies for January 2024 and January 2025 by comparing to the previous decade. The results showed notable shifts in wind speed intensity and distribution. January 2024 was significantly less windy.

Taking our analysis one step further,  we computed Lagrangian Coherent Structures (LCS) for both periods to assess zones of convergence and potential biological aggregation. See one of our earlier posts for our white paper on LCS methodology. The resulting LCS fields reveal very distinct differences between the years - zones of stronger attraction are shown in red while the weaker ones are blue on the plot.

Could such variations in ocean physics affect plankton distribution and, by extension, Blue Whale presence? LCS reveals key oceanic transport pathways, aiding marine biologists in understanding how flow patterns affect biomass distribution. Whales, for instance, likely use these structures to save energy during migration and foraging, as LCS highlight areas where prey concentrates due to converging waters and enhanced productivity.

It would be an interesting project to revisit previous years' survey data and re-run LCS using our high-resolution 3D hydrodynamic model. If you're working on Blue Whale ecology or interested in linking biological observations with physical ocean processes, please get in touch to discuss.

We are keen to collaborate and co-publish.