1Upwelling zones are as rich in fish as they are versatile and fragile: in the Humboldt current system, off the coasts of Peru and Chile, water productivity drops with every El Niño episode. Off the coast of Namibia, overfishing led to the proliferation of jellyfish, preventing fishable species from returning to their habitat. Consequently, the proper understanding of the physical, geochemical and biological dynamics of upwelling is a research topic of primary importance for many countries of the Global South. Upwelling dynamics are however complex and difficult to study for many Southern countries.

LOCEAN IPSL Senegalese upwelling model.

••• IRD provides the countries of the Global South with models simulating upwelling dynamics ••• 

Average surface chlorophyll. The four major upwelling systems are circled.

2While some models simulate how these processes work, they are fairly difficult to operate and require a high level of theoretical skills, as well as supercomputers with computational power not always available in the countries of the Global South. Hence the idea of adapting the models to this reality by creating tools to make them more easily accessible and capable of running on standard computers. This is how IRD and its partners have adapted the Roms ocean modelling system (renamed Croco) over the past two decades, to simulate ocean currents.

Upwelling along Senegal’s coastline.

3Croco uses grids interlocked with each other to achieve a fairly fine spatial resolution at lower computing costs. It is also combined with systems which simulate geochemical and biological cycles, respectively modelling the supply of nutrients (Pisces) and the life cycle of fish (Ichtyop). It therefore consists of two separate modules which adjust to requirements. It is used by nearly 1,500 researchers and engineers worldwide, particularly in West Africa, Madagascar and South-East Asia, to independently monitor and understand upwelling developments, among other things.

“I received a doctorate from the University of Cape Town (South Africa) as part of IRD’s structures. I also had the opportunity to visit several research institutes in Brest and interact with experts in physical oceanography and ocean modelling. This specific training was important to me, as I developed skills which helped me find a job. In addition, it was important for marine science in the region to gain a better understanding of ocean circulation in the South-west Indian Ocean. Better management practices can now be implemented in the region thanks to this improved understanding of ocean circulation, combined with the dynamic of marine ecosystems.” 
Dr Issufo Halo, physical oceanographer, Cape Peninsula University of Technology, Cape Town, South Africa