Temperatures in the Arctic, for example, have been rising much faster than the rest of the planet. Experts, for the longest time, have attributed the crisis to how clouds interact with sea ice, essentially frozen seawater.

Role of Polynya

• Decades of research have pointed that the losses in Arctic Sea ice cover allow for the formation of more clouds near the ocean’s surface.
• New research by NASA has now shown that more heat and moisture is released through a large hole in sea ice called a polynya, which fuels the formation of more clouds.
• This traps heat in the atmosphere and hinders the refreezing of new sea ice.

What is Polynya?

• A polynya is an area of open water surrounded by sea ice.
• It is now used as a geographical term for an area of unfrozen seawater within otherwise contiguous pack ice or fast ice.
• It refers to a natural ice hole and was adopted in the 19th century by polar explorers to describe navigable portions of the sea.
• There are two main types of polynyas:

1. Coastal polynyas, which can be found year-round near the Antarctic and Arctic coasts and are mainly created by strong winds pushing the ice away from the coast, and
2. Mid-sea or open-ocean polynyas, which may be found more sporadically in the middle of an ice pack in certain locations, especially around Antarctica.

What is the new research about?

• The research stated that low clouds over the polynya emitted more energy or heat than clouds in adjacent areas covered by sea ice.
• The polynya did refreeze, but only after the increased cloud cover and heat under the clouds persisted for about a week.
• The extra clouds and increased cloud radiative effect to the surface remained for some time after the polynya froze.
• The sea ice acts like a cap or a barrier between the relatively warm ocean surface and the cold and dry atmosphere above, so more heat and moisture from the ocean into the atmosphere.
• This warming slows down the growth of the sea ice.

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