In this 700 km wide geographical bottleneck, navigators have no escape from depressions that can reach 1000 km in diameter. Unlike the rest of their navigation in the southern hemisphere, where they can bypass storms to the north or south. In addition, this passage is particularly dangerous because of the icebergs or other pieces of ice that have broken off and are not necessarily detected by satellites.

SENSORS, SATELLITES AND DIGITAL MODELS TO BETTER UNDERSTAND OCEAN CURRENTS

The oceans are in motion. The wind generates the waves, the Moon and the Sun cause the tides, the rotation of the Earth generates whirlpools. And to add the vertical dimension, the cold and salty water plunges. A vast oceanic conveyor belt thus transports each drop of water around the world, from the surface to the bottom and from the bottom to the surface.

Clément Vic tells us more about the scientific questions he still has about this current mechanics: “We know relatively well how water sinks to the bottom, we know less well how water rises to the surface. The interactions between currents and the ocean floor generate turbulence and specific points of water upwelling. Our latest studies show that the rise of water drops depends on the topography; for example on reliefs like the Mid-Atlantic Ridge, water rises at multiple points”. Why is it important today to better understand this dynamic of ocean currents? Because they have a decisive impact on our climate. The best-known current, and yet not the strongest, is for example the Gulf Stream, whose extension, the North Atlantic Current, drains mildness and humidity towards Europe and which explains why we do not have a Canadian climate on our coasts.

However, climate change disrupts ocean currents. For example, the melting of ice increases and accelerates the flow of fresh water at the poles with less salty, lighter surface water. How will our conveyor belt react in the coming decades? Is there a risk of it seizing up? To answer this question, scientists are deploying measuring devices in all the world’s oceans, for example with the Argo float network. They also use surface observations made using satellites equipped with sensors. Finally, they solve the equations that govern the movements of the oceans using computer calculations. A way to predict what may happen in future climates by 2050 or 2100.

Because the ocean is a significant heat reservoir compared to the atmosphere. Water has a capacity a thousand times greater than air to absorb energy. The ocean thus functions like a sponge that absorbs excess heat from the atmosphere as well as 25% of the CO2 emitted by human activities