Sunday, 28 August 2016

The Arctic ice melt and the jetstream

Sam Carana on the Arctic melt
 



Via Facebook

As the Arctic warms faster than the rest of the world, the temperature difference between the Equator and the Arctic decreases, slowing down the speed at which the Northern Polar Jet Stream circumnavigates Earth, and making it wavier.

As a result, the Jet Stream can extend far over North America and Eurasia, making that cold air is moving out of the Arctic (e.g. deep into Siberia), while warm air moves in (e.g. from the Pacific Ocean). This also makes that the Jet Stream can more easily cross East Siberia and cause stormy weather over the Arctic Ocean.



This is illustrated by this image. The left panel shows the jet stream crossing East Siberia at speeds as high as 277 km/h or 172 mph on August 27, 2016, with cyclonic winds occurring over the Arctic ocean reaching speeds as high as 78 km/h or 48 mph that day.

The right panel shows that, on that day, cold air moved deep into Central Siberia, resulting in temperatures as lows as -15.9°C or 3.5°F in Central Siberia and temperatures that were higher than they used to be over the Arctic Ocean.

With the thicker multi-year sea ice now virtually gone, the remaining sea ice is prone to fracture and to become slushy, which also makes it darker in color and thus prone to absorb more sunlight

If strong winds keep hitting the Arctic Ocean over the next few weeks, this could push much of the sea ice out of the Arctic Ocean, along the edges of Greenland and into the Atlantic Ocean.


As sea ice extent falls, less sunlight gets reflected back into space and is instead absorbed by the Arctic. Furthermore, once the sea ice is gone, ocean heat will no longer be absorbed by melting, which can contribute to a rapid rise in temperature of the water.

Where seas are shallow, a surface temperature rise can quickly warm up water all the way down to the Arctic ocean seafloor, where it can destabilize methane hydrates contained in sediments.

This could make that huge amounts of methane get released from the seafloor. Given that many of the seas in Arctic are very shallow, much of this methane can enter the atmosphere without getting broken down in the water, resulting in huge additional warming, especially over the Arctic.

As discussed in an earlier post, this could contribute to a global temperature rise of over 10°C or 18°F by the year 2026. 
http://arctic-news.blogspot.com/…/arctic-sea-ice-getting-te…

The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan. 
http://arctic-news.blogspot.com/p/climateplan.html

From the post 'Storms over Arctic Ocean', at: 
http://arctic-news.blogspot.com/…/storms-over-arctic-ocean.…



This image shows how little sea ice was left at locations close to the North Pole on August 25, 2016. 

From the post 'Storms over Arctic Ocean', at: http://arctic-news.blogspot.com/2016/08/storms-over-arctic-ocean.html


Conditions in the Arctic today

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