Earth’s ocean is incredibly large. Parts of it are so remote that the closest human settlement is the International Space Station. What’s happening in the oceans as the world warms? with The ocean – will be vital to all our lives. But to watch what’s happening in distant waters, we need to study the ocean from space.

Late last year, NASA and the French space agency CNES launched a satellite that promises to give scientists a better picture of the ocean surface than ever before. The Surface Water and Ocean Topography (SWOT) mission will identify ocean currents that play critical roles in weather and climate.

To make the most of satellite observations, we need to compare them with measurements taken at surface level. That’s why we’re heading to sea aboard CSIRO’s state-of-the-art research vessel, RV Investigator, to collect vital ocean data as the satellite moves as it orbits the Earth.

current events

Climate change is disrupting the global network of currents that connect the oceans. Researchers have discovered a slowdown in the deep “tipping circulation” that carries carbon, heat, oxygen and nutrients from Antarctica to around the world. Meanwhile, at the surface, ocean currents become more energetic.

We have also seen dramatic changes in fast, narrow rivers of seawater called Western Boundary Currents, such as the Gulf Stream and the East Australian Current. These currents transport heat from the tropics to the poles and have become hot spots for warming oceans in recent years. They are warming two to three times faster in the southern hemisphere than the global average.

When these currents become unstable, they change the way heat is distributed in the ocean. This will lead to major changes in local air and marine ecosystems that could affect the lives of millions of people.

playground physics

The SWOT satellite mission will provide researchers with a powerful new tool to monitor changes in ocean currents using precise satellite measurements of the sea surface along with a bit of playground physics.

The satellite is equipped with a device that will image fluctuations in sea surface height in unprecedented detail. These differences can be less than a meter high over horizontal distances of hundreds of kilometers. But oceanographers can use measurements to estimate the ocean currents flowing beneath them.

Small changes in sea surface elevation create horizontal pressure differences that attempt to push water from high sea level to low sea level. This pressure difference is balanced by the Coriolis force, which slowly deflects ocean currents to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

You can feel the Coriolis force on the playground. Stand on the carousel and ask a friend to stand on the opposite side of you. When you start spinning, throw the ball to your friend. You will notice that the ball deviates from the direction of rotation.

Now imagine that the carousel is the Earth and the ball is an ocean current. The Coriolis deflection is sufficient to offset pressure differences of hundreds of kilometers, causing seawater to flow as ocean currents.

science at sea

By carefully measuring sea surface height and using our knowledge of the Coriolis force, oceanographers will be able to use data from NASA’s satellite to reveal ocean currents in greater detail than ever before. But to make sense of this data, researchers need to compare satellite measurements with observations made here on Earth.

That’s why we’ll be leading this journey with more than 60 scientists, support staff and crew aboard RV Investigator, Australia’s national flagship for blue water ocean research.

Our 24-day voyage will examine ocean dynamics off the southeast coast of Australia using Investigator’s world-class scientific equipment, including floating buoys and satellite-tracked drifters that will be used to measure ocean surface currents in real time.

The trip is part of a larger collaboration of scientists from around the world to collect observational data on the satellite’s orbit around Earth. This data will help validate satellite measurements and improve weather forecasts, including from the Australian Bureau of Meteorology, and assist with climate risk assessment and forecasting. We hope to better understand how our oceans are changing by using what we observe from space, the sea, and the playground. Source