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

Tuesday 18 August 2015

Disappearance Of Thick Arctic Sea Ice

[ view full image at facebook ]


Arctic sea ice is in a horrible state. On August 16, 2015, Arctic sea ice extent was 5.786 million square km, the smallest extent on record for this time of year except for the years 2007, 2011 and 2012, as illustrated by the image on the right.

The situation today is even worse than one might conclude when looking at sea ice extent alone. Thick sea ice is virtually absent compared to the situation in the year 2012 around this time of year, as illustrated by the image below comparing sea ice thickness on August 16, 2012 (left) with August 16, 2015 (right).


The ice used to be over 4 m thick, or over 13 ft thick, north of Greenland and the Canadian Archipelago. This thick multi-year ice has been a feature of the Arctic sea ice for over 100,000 years. It used to be there all year long, unlike the thinner ice that could melt away entirely during the melting season.

The disappearance of this thick multi-year ice is a major development. Why? Until now, the thicker multi-year sea ice used to survive the melting season, giving the sea ice strength for the next year, by acting as a buffer to absorb heat that would otherwise melt away the thinner ice. Without multi-year sea ice, the Arctic will be in a bad shape in coming years, and huge amounts of heat that would otherwise go into melting the ice will instead be warming up the Arctic Ocean, further accelerating warming of its waters.

Absence of thick sea ice makes it more prone to collapse, and this raises the question whether the sea ice could collapse soon, even this year. Sea ice works like a mirror. Without sea ice, sunlight that was previously reflected back into space, will instead be absorbed by the Arctic. Albedo changes in the Arctic alone could more than double the net radiative forcing resulting from the emissions caused by all people of the world, as calculated by Prof. Peter Wadhams back in 2012.

Furthermore, there is a danger that loss of the sea ice will weaken the currents that currently cool the bottom of the sea, where huge amounts of methane may be present in the form of free gas or hydrates in sediments. This danger is illustrated by the image below by Reg Morrison, from an earlier post.


Absence of sea ice also goes hand in hand with opportunities for storms to develop over the Arctic Ocean. Such storms could push the remaining sea ice out of the Arctic Ocean. Such storms could also mix surface heat all the way down to the seafloor, where methane could be contained in sediments.

As described in an earlier post, sea surface anomalies of over 5 degrees Celsius were recorded in August 2007 (NOAA image right). Strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007, as described in this study, and bottom water temperatures on the mid-shelf increased by more than 3 degrees Celsius compared to the long-term mean.

Indeed, the danger is that heat will warm up sediments under the sea, containing methane in hydrates and as free gas, causing large amounts of this methane to escape rather abruptly into the atmosphere.

The image on the right, from a study by Hovland et al., shows that hydrates can exist at the end of conduits in the sediment, formed when methane did escape from such hydrates in the past.

Heat can travel down such conduits relatively fast, warming up the hydrates and destabilizing them in the process, which can result in huge abrupt releases of methane.

Since waters can be very shallow in the Arctic, much of the methane can then rise up through these waters without getting oxidized. As the methane causes further warming in the atmosphere, this will contribute to the danger of even further methane escaping, further accelerating local warming, in a vicious cycle that can lead to catastrophic conditions well beyond the Arctic. For additional feedbacks in the Arctic, see the feedbacks page

At the same time, ocean heat is at a record high and there's an El NiƱo that's still gaining strength. This ocean heat is likely to reach the Arctic Ocean in full strength by October 2015, at a time when sea ice may still be at its minimum. The image below shows sea surface temperatures on August 16, 2015 (left) and anomalies (right).


How warm is the water entering the Arctic Ocean? Merely looking at sea surface temperatures could make one overlook the full extent of the predicament we are in. Ocean heat traveling underneath the sea surface can be even warmer than temperatures showing up at the surface. This is illustrated by the image below indicating that on August 16, 2015, warm water emerged at the sea surface near Svalbard with temperatures as high as 14.9°C or 58.7°F, a 9.5°C or 17.1°F anomaly.


There still is about a month to go before sea ice can be expected to reach its minimum, at around half September 2015, while sea currents will continue to carry warmer water into the Arctic Ocean for months to come.

The situation is dire and calls for comprehensive and effective action, as discussed in the Climate Plan


Thick sea ice is virtually absent compared to the situation in the year 2012 around this time of year, as illustrated by...
Posted by Sam Carana on Tuesday, August 18, 2015

Friday 24 July 2015

Thick Sea Ice Dislodged

As the comparison image below shows, the last bit of thick sea ice has become dislodged from its location in the Canadian Archipelago and is forecast to be floating along with the sea ice in the Arctic Ocean. The left panel shows the situation on July 19, 2015, while the right panel shows a forecast for July 31, 2015, run on July 23, 2015.


One reason for this development is of course the heavy melting that has taken place in this area. But what has made this thick sea ice move so strongly? The reason for this is a combination of wind, sea currents and meltwater running off the coasts of North America and Greenland. This has been persistently pushing this thick ice in this direction, as illustrated by the Naval Research Laboratory animation below.


The Naval Research Laboratory animation below shows sea ice thickness over a 30-day timespan, including a forecast up to 31 July, 2015, run July 23, 2015.


The screenshot below from arctic-io shows the sea ice on July 23, 2015, with an inset showing a rotated outcut from a Naval Research Laboratory ice thickness map for that date.
[ click on image to enlarge ]
The animation below shows a 5-day forecast of ice speed and drift up to July 27, 2015, starting from and run on July 23, 2015.


Furthermore, there has been a lot of smoke from wildfires in North America for some time. The image below shows smoke reaching far into the Beaufort Sea on July 22, 2015.



When smoke settles on snow and ice, it decreases albedo and makes it more prone to melting.

Seismic activity could also have contributed to this development. As the snow and ice cover on land disappears, isostatic rebound occurs, i.e. the land moves upward. Furthermore, an earthquake with a magnitude of 3.6 on the Richter scale was registered in Baffin Bay on July 22, 2015.


Above animation shows the last bit of thick sea ice becoming dislodged from its location in the Canadian Archipelago, from July 21, 2015, through to July 24, 2015.


Albert Kallio comments: "The more ice moves, the more heat it can pick up from the ocean - and melt. Also, the overturning of sea water in the ocean increases in the increasingly open sea areas - bringing heat up to the surface - and into contact with ice that then melts faster."

[ hat tip to Patrick McNulty for contributions to this post ] 



The last bit of thick sea ice has become dislodged from its location in the Canadian Archipelago and is forecast to be...
Posted by Sam Carana on Friday, July 24, 2015

Sunday 19 July 2015

Arctic Sea Ice Collapse Threatens - Update 1

The image below compares the Arctic sea ice thickness (in m) on July 15, for the years from 2012 (left panel) to 2015 (right panel), using Naval Research Laboratory images.

Click on image to enlarge
The image below compares the Arctic sea ice concentration (in %) on July 18, for the years from 2012 (left panel) to 2015 (right panel), using Naval Research Laboratory images.


Above images show the dramatic decline of the sea ice in 2015, both in thickness and in concentration.

In terms of thickness, sea ice has been reduced by more than one meter in many places, such as north of Greenland and the Canadian Archipelago, all in the time span of just one month.

The dramatic fall in sea ice concentration also becomes apparent when comparing recent sea ice concentration (July 18, 2015, above right) with sea ice concentration back in May 2015 (image right, May 1, 2015).

This dramatic decline of the sea ice in 2015 is the result of a combination of factors, including:

  1. High levels of greenhouse gases over the Arctic Ocean, as illustrated by the image below, showing that on July 17, 2015 (pm), levels as high as 2512 parts per billion were recorded at 6,041 m (19,820 ft) altitude, while mean methane levels were 1830 parts per billion at this altitude.
  2. High levels of ocean heat, as illustrated by the image below showing high sea surface temperatures off the east coast of North America; much of this ocean heat will be carried by the Gulf Stream into the Arctic Ocean over the next few months.
  3. High air temperatures over North America and Siberia extending over the Arctic Ocean, as illustrated by the image below showing a temperature of 23.1°C (73.7°F), recorded on July 19, 2015, at Banks Island, in the Canadian Archipelago (green circle).
  4. Wildfires triggered by these heatwaves resulting in darkening compounds settling on snow and ice, as illustrated by the image below showing smoke covering a wide area on July 19, 2015, from the east Siberia over North America to the southern tip of Greenland.
  5. Very warm river water running into the Arctic Ocean, as illustrated by the image below, showing sea surface temperatures as high as 19°C (66.2°F) off the coast of Alaska on July 12-15, 2015.
The image below shows the already very high sea surface temperature anomalies as at July 18, 2015.

The Climate Reanalyzer image below shows the high sea surface temperature anomalies in the Pacific Ocean, and where water enter the Arctic Ocean through the Bering Strait, on July 19, 2015.



With still two months of melting to go before the sea ice can be expected to reach its minimum for 2015, the threat of sea ice collapse is ominous. The Arctic-News Blog has been warning for years about the growing chance of a collapse of the sea ice, in which case huge amounts of sunlight that previously were reflected back into space, as well as heat that previously went into melting the ice, will then instead have to be absorbed by the water, resulting in a dramatic rise of sea surface temperatures.

More open water will then come with an increased chance of storms that can cause high sea surface temperatures to be mixed down all the way to seafloor of the Arctic Ocean, which in many cases is less than 50 m (164 ft) deep. This is the case for the East Siberian Arctic Shelf, where experts estimate that huge amounts of methane are contained in subsea sediments. Already now, sea surface temperatures as high as 10°C (~50°F) are recorded there, as illustrated by the image below.


Massive amounts of ocean heat will be carried by the Gulf Stream into the Arctic Ocean over the next few months. The combined result of high sea surface temperatures being mixed down to the seafloor and the ocean heat entering the Arctic Ocean from the Atlantic and Pacific Oceans can be expected to result in dramatic methane eruptions from the Arctic Ocean seafloor by October 2015.

The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.



Arctic sea ice thickness on July 15, compared over the years 2012 through to 2015. Already virtually all the thick sea...

Posted by Sam Carana on Thursday, July 16, 2015

Friday 10 July 2015

Arctic Sea Ice Collapse Threatens

The image below compares the Arctic sea ice thickness on July 14, 2012 (left panel) and on July 14, 2015 (right panel), using Naval Research Laboratory images.


The Naval Research Laboratory's 30-day animation below shows how this situation developed, ending with a forecast for July 17, 2015, run on July 9, 2015.


The dramatic decline of the sea ice, especially north of North America, is the result of a combination of factors, including:

  • very high levels of greenhouse gases over the Arctic Ocean
  • very high levels of ocean heat 
  • heatwaves over North America and Siberia extending high air temperatures over the Arctic Ocean
  • wildfires triggered by these heatwaves resulting in darkening compounds settling on snow and ice
  • very warm river water running into the Arctic Ocean, as illustrated by the image below.  


With still two months of melting to go before the sea ice can be expected to reach its minimum for 2015, the threat of sea ice collapse is ominous. The Arctic-News Blog has been warning for years about the growing chance of a collapse of the sea ice, in which case huge amounts of sunlight that previously were reflected back into space, as well as heat that previously went into melting the ice, will then instead have to be absorbed by the water, resulting in a dramatic rise of sea surface temperatures.

The image below shows the already very high sea surface temperature anomalies as at July 10, 2015.


More open water will then come with an increased chance of storms that can cause high sea surface temperatures to be mixed down all the way to seafloor of the Arctic Ocean, which in many cases is less than 50 m (164 ft) deep.

Meanwhile, ocean heat is accumulating off the coast of North America, as illustrated by the image below showing sea surface temperature as high as 31.8°C (89.24°F) on July 8-9, 2015.


Massive amounts of ocean heat will be carried by the Gulf Stream into the Arctic Ocean over the next few months. The combined result of high sea surface temperatures being mixed down to the seafloor and the ocean heat entering the Arctic Ocean from the Atlantic and Pacific Oceans can be expected to result in dramatic methane eruptions from the Arctic Ocean seafloor by October 2015.

Currently, methane levels are high, especially north of Greenland, as illustrated by the image below showing that on July 10, 2015 (am), levels as high as 2416 parts per billion were recorded at 6,041 m (19,820 ft) altitude, while mean methane levels also reached 1831 parts per billion at this altitude.


The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.





ARCTIC SEA ICE COLLAPSE THREATENSThis image compares the Arctic sea ice thickness on July 14, 2012 (left panel) and on...
Posted by Sam Carana on Friday, July 10, 2015

Wednesday 8 July 2015

Fracturing of the Jet Stream

Earlier this month, the jet stream was forecast to move over the Arctic Ocean north of Siberia on July 8, 2015, 12:00 UTC, in one, strong, long stream of wind, as discussed in the previous post and depicted below.


The situation has meanwhile been adjusted in a more recent forecast. This recent forecast shows the jet stream getting fractured over Siberia on July 8, 2015, 12:00 UTC, resulting in a sequence of vertical wind streams. This is a new development, rather unknown to the forecasting model that works on the basis of the jet stream flowing horizontally in one strong and narrow stream around the globe.


A further forecast has been added in the bottom panel, i.e. for July 12, 2015, 12:00 UTC, showing the jet stream moving well over the Arctic Ocean in two places, over the East Siberian Sea and over the Canadian Archipelago.

Fracturing of the jet stream and alignment along longitude, rather than latitude, is a worrying development. It is the most extreme form of what is described at Feedbacks in the Arctic as the "Open Doors" feedback or feedback #10, a feedback that makes it easier for warm air to move into the Arctic and for cold air move out of the Arctic, each of which will further contribute to a smaller temperature difference between the Equator and the North Pole, thus further changing the jet stream, in a self-reinforcing spiral.

The jet stream used to act as a barrier, keeping cold air in the Arctic and keeping temperate air in the temperate zone. As the jet stream fractures, more extreme weather - including more intense heatwaves - can be expected.

The result is further acceleration of warming in the Arctic, due to direct sunlight, due to warm wind carried north as the jet stream changes, due to warm water from rivers flowing into the Arctic Ocean, due to soot from wildfires settling on the snow and ice, causing their further demise, etc.

The image below illustrates the impact of warm river water. Off the coast of Anadyr, in East Siberia, waters reached a temperature of 15.4°C (59.7°F) on July 5, 2015, a 9.2°C (16.6°F) anomaly.


The image below also shows the impact of warm water from rivers in Alaska. Major melting took place on St Lawrence Island, as evident by the low sea surface temperatures around the Island on July 2, 2015 (left panel), while by July 6, 2015, much of this colder water had mixed with the warmer water moving up the Bering Strait from the Pacific Ocean and with the warm river water from Siberia and Alaska.



The Naval Research Laboratory's 30-day animation below illustrates the dramatic fall in sea ice thickness.


The image below shows sea surface temperatures in the Arctic as at July 7, 2015.


With ocean heat at very high levels, the danger is that, as temperatures keep rising, further methane hydrates will get destabilized and further amounts of methane will be released in the Arctic. High methane levels have already been showing up for years over the Arctic Ocean, indicating that methane releases from the seafloor of the Arctic Ocean are already taking place.


Above image shows that, on July 6, 2015, high methane levels show up north of Greenland (yellow oval). This could be a result of the heavy melting that is taking place on Greenland, exposing methane hydrates contained in the ice there. Hydrate destabilization on Greenland is discussed as feedback#21 at Feedbacks in the Arctic. Loss of ice mass on Greenland has fallen dramatically over the years and looks set to get even worse, as illustrated by the image below.

Dramatic ice mass loss on Greenland looks set to get even worse. See also discussion at the Controversy page.
Over the next few months, waters in the Arctic Ocean can be expected to further warm up and sea ice to further decline, all making that the situation can only be expected to worsen.
The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.



Sea surface temperatures in the Arctic as at July 7, 2015. http://arctic-news.blogspot.com/2015/07/fracturing-of-the-jet-stream.html
Posted by Sam Carana on Wednesday, July 8, 2015

Tuesday 30 June 2015

Dramatic Sea Ice Decline In Beaufort Sea in June 2015

The image below illustrates the dramatic fall in sea ice thickness (in m) in the Beaufort Sea over the past month. The left panel shows sea ice thickness on May 29, 2015, and the panel on the right shows sea ice thickness on June 29, 2015.


The 30-day animation below further illustrates this dramatic fall in sea ice thickness (from June 8-29, with forecast up to July 7, 2015).




Another perspective is sea ice concentration. The image below shows the high concentration back on May 1, 2015.



The 30-day animation below shows the dramatic fall in sea ice concentration (from June 8-29, with forecast up to July 7, 2015).



Below an interview by Judy Sole with Professor Peter Wadhams, held May 15, 2015, and entitled 'Our time is running out - The Arctic sea ice is going!'


Meanwhile, very high temperatures keep showing up within the Arctic Circle. On July 1, 2015, a temperature of 36°C (96.8°F) was reached near the Kolyma River that ends in the East Siberian Sea, as illustrated by the images below (green circle).


The image below also shows the location where this high temperature was reached (red marker), as well as the depth of the seabed and the Gakkel Ridge that runs in between the northern tip of Greenland and the Laptev Sea.



Related

- High Methane Levels over Laptev Sea
http://arctic-news.blogspot.com/2013/10/high-methane-levels-over-laptev-sea.html

- Accelerated Warming in the Arctic
http://arctic-news.blogspot.com/2015/06/accelerated-warming-in-the-arctic.html

- Gulf Stream brings ever warmer water into Arctic Ocean
http://arctic-news.blogspot.com/2015/06/gulf-stream-brings-ever-warmer-water-into-arctic-ocean.html

- High Temperatures in the Arctic
http://arctic-news.blogspot.com/2015/06/high-temperatures-in-the-arctic.html

- Heat Wave Forecast For Russia Early June 2015 
http://arctic-news.blogspot.com/2015/06/heat-wave-forecast-for-russia-early-june-2015.html

Dramatic Sea Ice Decline In Beaufort Sea in June 2015 http://arctic-news.blogspot.com/2015/06/dramatic-sea-ice-decline-in-beaufort-sea-in-june-2015.html
Posted by Sam Carana on Tuesday, June 30, 2015

Thursday 28 May 2015

Arctic Sea Ice in Uncharted Territory

On May 27, 2015, Arctic sea ice extent was merely 11.973 million square kilometers, a record low for the time of the year since satellite started measurements in 1979.


This fall in sea ice extent follows heat waves in Alaska and the north of Canada, as illustrated by the image below.

Temperature in Alaska on the afternoon of May 23, 2015, when a temperature of 91°F (32.78°C) was recorded in Eagle
High temperatures extended over the Beaufort Sea and Chukchi Sea. The image below shows the difference in sea surface temperatures between May 13, 2015, and May 23, 2015.


The large amounts of meltwater flowing into Beaufort Sea and the Chukchi Sea is illustrated by the image below, showing the difference in sea surface salinity between May 17, 2015, and May 24, 2015.


Sea ice has retreated dramatically in the Chukchi Sea and the Beaufort Sea, and in Baffin Bay, with high sea surface temperature showing up where rivers flow into the Arctic Ocean and where the Gulf Stream carries warm water from the Atlantic Ocean into the Arctic Ocean.

The size-reduced navy.mil animations below show the fall in sea surface salinity (left) and the fall in sea ice thickness (right) in the Beaufort Sea, from May 3, 2015, to June 2, 2015 (run May 27, 2015).

Sea surface salinity Beaufort Sea
Sea ice thickness Beaufort Sea
   
The image below shows sea surface temperature anomalies on May 27, 2015.


For reference, the animation below, from the Naval Research Laboratory, shows sea ice thickness over a 30-day period, including a forecast up to June 4, 2015.


Update: here's an image showing Arctic sea ice extent up to May 28, 2015, highlighting that sea ice extent is now well outside 2 standard deviations.



The situation is dire and calls for comprehensive and effective action as discussed at the Climate Plan.



Arctic Sea Ice in Uncharted Territory Sea ice has retreated dramatically in the Chukchi Sea and the Beaufort Sea, and...
Posted by Sam Carana on Thursday, May 28, 2015