The first complete picture of Arctic sea ice freeze-thaw cycle highlights sea ice response to climate change

Climate change signals are amplified in the northern part of the planet and sea ice is sensitive to warming. The atmosphere and the ocean are affected by sea ice.

The freeze-thaw process at the bottom of the ice is not investigated by most studies.

In a new study published today in the European Geosciences Union journal The Cryosphere, an international team of scientists synthesised data from 2001 to 2018 to explore the temporal variations of both surface and basal melt/freeze onsets. The findings could help us understand changes in the atmosphere and sea ice in a changingarctic.

There is a possibility of a delay in the loss of sea ice.

Thinner ice thickness and thinner snow cover make it easier to start the freeze early. Long Lin explains that the ocean regulates the growth or decay of sea ice.

The researchers found that the start of the freeze was almost three months later than the surface. The ice freeze-up delay can be attributed to the regulation of heat capacity of sea ice itself and the ocean heat release from the ocean mixed layer.

The sea ice loss in the summer can't be offset by the total ice growth. The self-regulation of the ocean and sea in the north will delay the loss of sea ice.

There are new insights into the ice melt process.

The research found that the most significant temporal difference of melt onsets between surface and bottom was found in the Beaufort Gyre region. Both multiyear ice and first-year ice in this region show a trend towards earlier melt onset due to the earlier warming of the surface ocean.

The first complete picture of the sea ice freeze-thaw cycle is presented by these results. The importance of comprehensive monitoring of the air-ice-ocean system is highlighted.

Ice mass balance observations of diverse ice types and simultaneous upper ocean water properties should be done more often. The hope is that this will greatly improve our ability to understand the ocean.

Changes in the annual sea ice freeze–thaw cycle in theArctic Ocean from 2001 to 2018, The Cryosphere. There is a book titled "10.194/tc-16-4779-2022".

Journal information: The Cryosphere