61st Japanese Antarctic Research Expedition 2021.07.21
XCTD (eXpendable Conductivity Temperature Depth profiler)
Overview
Japan’s Antarctic research is conducted based on medium-term targets and plans in order to ensure systematic and efficient operation. Various research is currently being carried out based on Phase IX of the six-year Japanese Antarctic Research Project. The Antarctic research vessel 「Shirase」 is a famous observation platform, and the XCTD is used on the 「Shirase」 to perform Antarctic observation.
Project
The 61st Japanese Antarctic Research Expedition performed intensive observation offshore Antarctica’s Totten Glacier to learn more about the processes involved in its melting
If climate change causes warm seawater temperatures to rise further, the rate at which glaciers melt will inevitably rise. If all of the ice in the Totten Glacier watershed were to melt, forecasts show that it would cause the sea level to rise by roughly four meters.
The end of the Totten Glacier projects into the sea, and it has been discovered that warm seawater flowing underneath it is causing glacier melting. However, we still know little about the inflow routes of this warm seawater, the amount of water involved, seasonal changes, how the situation has changed over time, and the like.
In 2020, the 61st Japanese Antarctic Research Expedition became the world’s first research group to perform intensive observation off the shore of the Totten Glacier. Antarctica is 37 times the size of Japan. The sea ice around it is thick, so there are areas which are difficult for ships to approach. Performing research requires observation systems capable of efficiently measuring sea conditions over a wide area in this harsh environment.
The location of the end of the Totten Glacier. The blue line is the route taken by the Shirase Antarctic research vessel. © NiPR
Solution
Marine observation equipment that can be used from ships or aircraft while in motion
The intensive observation offshore the Totten Glacier was performed by deploying an XCTD (eXpendable Conductivity Temperature Depth profiler) into the sea while the Shirase was in motion to measure the vertical distribution of water temperatures and salinity.
In areas where wide-ranging research is difficult to perform from ships, the Shirase’s helicopter was used to deploy the Airborne XCTD (Airborne eXpendable Conductivity Temperature Depth profiler), an XCTD probe that can be deployed from the air. Even now, this equipment is being used to collect data used to assess warm water inflow routes and seasonal/temporal changes offshore the Totten Glacier.
XCTD probe being launched from the Shirase © NiPR
The AXCTD is deployed from the Shirase helicopter © NiPR
The numbers in the circles and diamonds are measurement point candidates © NiPR
Activity reports of the 61st and 62nd Japanese Antarctic Research Expeditions
The research expedition blog of the National Institute of Polar Research (NiPR) posts valuable information and activity reports that cannot be found anywhere else.
All members of the expedition returned to Japan safely again this year, and the blog has posted activity reports for the 61st Japanese Antarctic Research Expedition wintering party (February 2020 to January 2021) and the 62nd Japanese Antarctic Research Expedition summer party (November 2020 to February 2021).
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