Showing posts with label thickness. Show all posts
Showing posts with label thickness. Show all posts

Friday 2 January 2015

Strong winds threaten to push sea ice out of Arctic Ocean

By Albert Kallio


The lateral viscosity of the thin Arctic sea ice cover continues to lower. In November just one quarter of the high Arctic Ocean basin above 85° north was covered by a thin this winter's ice. This has now doubled, soon covering two quarters. The ice has been pushed away from Russia towards Canada and to the Fram Strait at phenomenal rates.
 
Animation by navy.mil showing 30 days of sea ice thickness, up to January 1, 2015
This is increasingly suggesting that the remaining half in front of the Fram Strait will be sucked into the Atlantic Ocean soon. The dark blue ice is newly formed crushed ice behind the North Pole (pack ice). We may well be in course to the first recorded ice free season in the Arctic Ocean. In addition, the rear is pushed from behind Canada to the Beaufort and Chukchi Seas.

Animation by navy.mil showing 30 days of sea ice speed and drift, up to January 1, 2015

We need to act, now. I think we need to monitor this development almost on daily basis. I am curious to see how the ice may behave after the last remainders of the second quarter are sucked into the Atlantic Ocean and the newly forming sea ice will face the force of the Atlantic waves. That could mean extremely highly fractured sea ice across the Russian side by the return of spring 2015 sunlight.

I think we are witnessing a historic transition right now with no ice in the summers.



Sunday 25 May 2014

Large Falls in Arctic Sea Ice Thickness over May 2014

Comparing ice thickness (in meters) on May 2, 2014 (left) and May 30, 2014 (right, forecast run May 25, 2014)
Arctic sea ice has shown large falls in thickness in many areas over the course of May 2014, as shown on above image. The animation below also compares the situation between May 2, 2014, and May 30, 2014 (as forecast by Naval Research Laboratory on May 23, 2014). Ice thickness is in meters.


Thickness is an important indicator of the vulnerability of the ice. If only looking at sea ice extent, one might (wrongly) conclude that sea ice retreat was only minor and that everything looked fine. By contrast, when looking at thickness, it becomes evident that large falls have occurred over the course of May 2014.

Falls at the edges of the sea ice can be expected at this time of the year, but the large fall closer to the center is frightening. On the one hand, it appears to reflect cyclonic weather and subsequent drift of the ice. On the other hand, it also indicates how vulnerable the sea ice has become. Last year, a large area showed up at the center of the sea ice where the ice became very thin, as discussed in July 2013 in the post Open Water at North Pole and again in the September 2013 post North Hole.

The appearance of huge weak areas at the center of the sea ice adds to its vulnerability and increases the prospect of total sea ice collapse, in case of one or more large cyclones hitting the Arctic Ocean later this year. To highlight the dangerous situation, the main image from a post earlier this month is again added below.


Adding to the concerns are huge sea surface temperature anomalies, as illustrated by the image below, showing anomalies at May 23, 2014, and created by Harold Hensel with ClimateReanalyzer and Google Earth.

[ click on image to enlarge ]
The image below shows sea surface anomalies on May 26, 2014, with an overlay of land temperatures, as created by Harold Hensel and edited by Sam Carana.


The image shows sea surface temperatures on the Northern Hemisphere that are 1.44 degrees Celsius warmer than the baselline temperature, despite large areas with cold water partly resulting from the huge amounts of meltwater flowing down along the edges of Greenland into the North Atlantic Ocean. The graph below shows Northern Hemisphere and Global sea surface temperature anomalies over May 2014.

By comparison, current (May 27, 2014) surface temperature anomalies of 0.64°C globally and 0.84°C for the NH. The image below shows annual temperature anomalies (land and ocean data).



Meanwhile, the development of this year's 'north hole' at the center of the sea ice appears to persist, as illustrated by the image below.