Scientists travel to the Southern Ocean to investigate how climate change will affect the planet’s most powerful current

Scientists travel to the Southern Ocean to investigate how climate change will affect the planet’s most powerful current

November 13, 2023
New release

CSIRO Research Vessel (RV) investigator He heads into the heart of the Antarctic Circumpolar Current to investigate why warm water is seeping into the polar seas from the planet’s strongest current that helps keep Antarctica frozen.

The science team led by Australia’s national science agency, CSIRO, and the Australian Antarctic Program Partnership is seeking to understand how currents in the Southern Ocean contribute to the melting of Antarctic ice shelves.

The Antarctic Circumpolar Current plays an important role in understanding the impact of melting ice on sea surface rise, said Dr Benoit LeGracey, chief Voyage scientist from CSIRO.

“The Antarctic Circumpolar Current flows around the icy continent from west to east and acts as a safety belt for us so that warm water does not reach the Antarctic and melt the ice,” Dr LeGrisi said.

“But the Antarctic Circumpolar Current generates subtle eddies and dynamics that we are trying to understand, and which are the main suspects in warm water seeping toward the pole.

“There are five ‘eddy heat flux gateways’, or hotspots, identified around the Antarctic Circle that act as a gateway for heat to go south. We’ll be tracking down those small features that we think explain the escape of heat into polar waters.”

This flight will be the first time scientists have validated images of the Southern Ocean taken by the new Surface Water and Ocean Topography (SWOT) satellite, jointly developed by NASA and the French space agency Center National d’Etudes Spatiales (CNES).

While the ship measures the properties of the ocean within the current, the satellite will measure the height of the ocean surface from space. The SWOT satellite is revolutionizing how scientists monitor Earth’s rising waters with high-resolution 2 km pixel images.

As it passes over the Southern Ocean, it will have the highest resolution ocean topography yet from the Southern Ocean and the Antarctic Current.

These small-scale ocean features contribute to the redistribution of heat, carbon and energy in the ocean, which are major components of global climate change.

SWOT was a “satellite breakthrough mission,” said Dr. Rosemary Morrow, leader of the Ocean SWOT program at the National Center for Space Studies.

“Our first images already show the amazing 2D structure of oceanic eddies and fronts, and how they are stretched and strained by the turbulent ocean,” Dr. Morrow said.

“These small-scale ocean dynamics are key in moving heat and carbon across the ocean, but also in pumping it into the deep ocean interior.

“New SWOT observations, along with measurements taken on the RV investigatorwill usher in a new era, by expanding our knowledge from one-dimensional sections to full variations of three-dimensional oceans.

The expedition continues the tradition of highly collaborative international science focused on Antarctica and the preservation of the icy continent.

Lead researchers relying on data collected from the voyage as part of their ongoing research include scientists from the CSIRO, the University of Tasmania, the California Institute of Technology (Caltech), Woods Hole Oceanographic Institution, the University of Washington, and the Laboratory for Scientific Studies. Geophysics and spatial oceanography.

The flight departs Hobart this week and returns on December 20.

This research is supported by an RV Sea Time Grant investigator From the National Marine Facility CSIRO supported by the Australian Government’s National Cooperative Research Infrastructure Strategy (NCRIS).

Note to editors

Monitoring equipment used by scientists at RV Investigator includes:

Three autonomous gliders will be deployed in the deep sea. They travel up and down the water column to a depth of 1000 meters and can move against and across the current. This allows them to detail the structure of the stream. Deck gliders to transmit data and receive command instructions. They will be deployed for six months, continuously sampling the ocean over an area of ​​180 kilometers from north to south and a greater distance from west to east. One of the gliders belonged to the CSIRO and two to the California Institute of Technology. Once deployed, a team of pilots in Hobart (CSIRO), Pasadena (Caltech), and New York (Brown University) will fly the gliders for six months.

Long strap
The 3.6-kilometre-high anchorage will be anchored with three one-ton anchors in the center of the search area for 18 months. The ship is conducting experiments with other monitoring equipment around the long anchorage equipped with buoys and 35 instruments. While the anchor is set, the devices will measure currents, temperature, salinity and oxygen continuously and capture data every 10 minutes for 18 months.

The Triaxus is towed behind the RV Investigator and has wings that allow the onboard operator to guide it through the water, identifying water features at a depth of 300 metres. New instruments from Woods Hole Oceanographic Institution will provide data on the fine structure of the water, measuring velocity, temperature, salinity and turbulence. Triaxos will be directed to synchronize with the satellite as it passes through the sky, validating the ocean data and supplementing it with satellite data.

The lost ones
Fifteen floating vehicles will be deployed and float freely on the ocean surface to provide information on current trajectories and ocean dynamics, calibrated against satellite data.

Argo floats
Six Argo buoys will be deployed. All of these devices will measure temperature, salinity, dissolved oxygen and other biochemistry as they drift with the currents. Three will also measure the turbulence or microstructure of the stream.

CTD Rosette
The conductivity, temperature and depth (CTD) rosette can reach the ocean floor and will be deployed 130 times during the journey. In addition to measuring current, it measures temperature, salinity, oxygen, nutrients, fluorescence and dissolved carbon and takes water samples for further analysis. Scientists will analyze the ocean’s carbon uptake and phytoplankton diversity.

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *