Scientists are trying to find out why sea ice is growing in some parts of Antarctica even though the sea is becoming a little bit warmer.
Part of the answer to this puzzle lies in the effect that the warmer sea is also having on Antarctic ice shelves – the glacier ice that spreads out from the land and on to the sea.
Melting of ice shelves by the sea creates water that becomes supercooled as it rises to the surface. This very cold water makes the sea ice get thicker.
Why is the area of sea ice around Antarctica growing?
While the total area of sea ice is growing, it is different in different places. This is not a surprise as the sea around Antarctica also varies from place to place.
Changing winds are also thought to be changing ice growth in some places.
The K131 science team are interested in how ice shelves and the sea affect each other. Ice shelves are made of fresh water so when they melt they release very cold, fresh water into the sea.
This water is so cold it can be below its freezing point, yet it still is a liquid – this water is called supercool. This supercool water tries to form new ice.
It is possible that the current pattern of more sea ice over winter in Antarctica is partly caused by the melting of the ice shelves. One form of ice is being replaced by another.
What the scientists will be working on
NIWA scientists have been working in Antarctica to try and understand the processes that lead to the growth of sea ice in parts of Antarctica. During the field trip you will meet Dr Natalie Robinson who will be looking at how ice crystals grow and group together in supercooled water. Natalie will then test how the ice crystals below sea ice affect the movement of water and the way heat moves through the sea.
Measurements will be collected on;
- Supercooled water
- Temperature
- Salinity
- Turbulence (movement of water)
- Ice crystal growth.
By collecting this data, scientists hope to find more accurate information about changes in the ice shelf and sea ice. This information will be fed into climate models to make them more accurate. By improving climate models scientists will better be able to show what the future climate will be like.
