Showing posts with label minimum. Show all posts
Showing posts with label minimum. Show all posts

Tuesday, September 22, 2015

Arctic Sea Ice 2015 - Update 10

It looks like sea ice has passed its minimum extent for the year 2015, as illustrated by the image below.


There are some differences between the various websites measuring extent, such as to whether the 2015 low was the third or fourth lowest. Japanese measurements show that sea ice extent was 4.26 million square km on September 14, 2015, i.e. lower than the 2011 minimum of 4.27 million square km, as illustrated by the image below.


Meanwhile, the Polar Science Center at the University of Washington has announced that Arctic sea ice volume minimum was reached on September 12, 2015, with a total volume of 5,670 cubic km. The image below shows a polynomial trendline based on their annual Arctic sea ice volume minima, including this volume for 2015.


Importantly, the sea ice in many places is now less thick than it was in 2012, as illustrated by the image below, showing sea ice thickness on September 27, 2012 (panel left) and a forecast for September 27, 2015 (panel right).


The reason for the dramatic decrease in thickness of the multi-year sea ice is ocean heat, as illustrated by the image below, showing sea surface temperature anomalies in the Arctic as at September 21, 2015.


The water of the Arctic Ocean is very warm, not only at the surface, but even more so underneath the surface. What has contributed to this situation is described by the image below. From 2012, huge amounts of fresh water have run off Greenland, with the accumulated fresh water now covering a huge part of the North Atlantic.

Since it's fresh water that is now covering a large part of the surface of the North Atlantic, it will not easily sink in the very salty water that was already there. The water in the North Atlantic was very salty due to the high evaporation, which was in turn due to high temperatures and strong winds and currents. As said, fresh water tends to stay on top of more salty water, even though the temperature of the fresh water is low, which makes this water more dense. The result of this stratification is less evaporation in the North Atlantic, and less transfer of ocean heat to the atmosphere, and thus lower air temperatures than would have been the case without this colder surface water.


Meanwhile, global warming continues to heat up the oceans, while less of this ocean heat can now be transferred from the water to the atmosphere in the North Atlantic, since the fresh water is acting like a lid.

The danger is thus that warmer water will be pushed into the Arctic Ocean at lower depth, and that it will reach the seafloor of the Arctic Ocean where huge amounts of methane are contained in sediments. Ice acts like a glue, holding these sediments together and preventing destabilization of methane hydrates. Warmer water reaching these sediments can penetrate them by traveling down cracks and fractures in the sediments, and reach the hydrates.

The big melt in Greenland and the Arctic in general is causing further problems. Isostatic adjustment following melting can contribute to seismic events such as earthquakes, shockwaves and landslides that can destabilize methane hydrates contained in sediments on the Arctic Ocean seafloor.

In the video below, by Nick Breeze, Professor Peter Wadhams discusses the situation.



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


The water of the Arctic Ocean is very warm, not only at the surface, but even more so underneath the surface. What has...
Posted by Sam Carana on Tuesday, September 22, 2015

Sunday, June 16, 2013

Arctic Sea Ice September 2013 Projections

What will the Arctic Sea Ice look like in September 2013?

Several projections for Arctic sea ice extent are being discussed at places such as ARCUS (Arctic Research Consortium of the United States) and the Arctic Sea Ice Blog. The image below, from ARCUS, shows various projections of September 2013 arctic sea extent (defined as the monthly average for September) with a median value of 4.1 million square kilometers, with quartiles of 3.8 and 4.4 million square kilometers.


Note that sea ice extent in the above projections is defined as area of ocean with at least 15% ice, in line with the way the NSIDC calculates extent. By contrast, the Danish Meteorological Institute includes areas with ice concentration higher than 30% to calculate ice extent.

Rather than looking at the projected average for September, one could also project the minimum value for September 2013. And rather than looking at sea ice extent, one could also look at sea ice area, which differs from sea ice extent as the NSIDC FAQ page describes:
A simplified way to think of extent versus area is to imagine a slice of Swiss cheese. Extent would be a measure of the edges of the slice of cheese and all of the space inside it. Area would be the measure of where there is cheese only, not including the holes. That is why if you compare extent and area in the same time period, extent is always bigger.


Above image shows Sam Carana's projected minimum area of 2 million square km for 2013, based on data by Cryosphere Today and on numerous factors, such as continued warming of the water underneath the ice, stronger cyclones, etc.
Roughly in line with above image, by Wipneus, Sam Carana's projection for Arctic sea ice minimum volume is 2,000 cubic km in September 2013.

Readers are invited to submit comments below with further projections.

Wednesday, April 24, 2013

Arctic Sea Ice Animation

Arctic Sea Ice Minimum Volume

Above a tilted screenshot from the animation below, by Andy Lee Robinson, of Arctic Sea Ice minimum volumes reached every September since 1979, based on data from the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS, Zhang and Rothrock, 2003) at the University of Washington.

Andy also composed and performed the piano music, "Ice Dreams", accompanying the video.

video from https://www.youtube.com/watch?v=YgiMBxaL19M


Dorsi Diaz
By Dorsi Diaz

They say a picture can be worth a thousand words. If so, then this video of the Arctic Sea ice loss between 1979 and 2012 must be worth a million. As the recently released video begins to go viral, more people are waking up to the reality of climate change.

Produced by Andy Lee Robinson, this beautiful short clip with its haunting music is revealing the reality of climate change in a brutal and honest way - perhaps even better than any journalist ever could.

In an interview with Robinson, I was amazed at how he had managed to put together this vital information in such a compelling video, and sought to find out more.

To the climate deniers horror, Andy has done this video with no sort of compensation - dashing away climate deniers theories that all climate activists "are on the payroll." With hundreds of painstaking hours put into the development of his video, Andy says he was motivated by "experimenting with ideas and what ifs" and sought to "bring to life something that only existed in my mind to communicate an important message that is being ignored."

To create the video, he used a text editor, numbers and only his imagination to weave together the horrifying decline of Arctic sea ice that has occurred in just 13 short years.

Andy says one of the reasons for creating the video was, "to contribute something to humanity and be recognized for it, applying the skills I have learnt with my free time and not to live in vain" and also, "to prove that anyone can achieve anything they want to given enough determination and dedication."

With over 100 hours invested just into the writing of the program for the video, Andy also said it took 28 hours for 7 servers to render the final video, then about a half hour to write, record, edit and merge the music. The piano composition in the video, "Ice Dreams", was also composed by Andy, who also specializes in digital audio sampling and signal processing.

Robinson, a linux system administrator and consultant, has a passion to bring awareness about climate change to the masses and is adamant about what may happen if civilization does not address this growing threat: "We are in a period of mass extinction and heading for decimation of the quality of life for most lifeforms on the planet, including ourselves who are also subject to the laws of nature of boom and bust as resources are exploited and depleted."

Robinson also believes, with many others, that climate change and ocean acidification are, "planetary emergencies in progress."

Robinson doesn't mince any words either when asked why he created the video: "To be heard loudly and truthfully because mainstream media is still tiptoeing around the herd of elephants in the room because of the fear of change and the pressure of special interests committed to ensuring it stays that way, ignoring the fact that it cannot."

Until recently, climate deniers had dominated much of the political landscape and held a tight reign on the mainstream media. Now that climate change seems to be spiraling out of control with billions of dollars in weather related disasters, people are waking up to a preview of what it's like to live in a climate altered world.

Robinson's research for the video uses records of Arctic sea ice loss from PIOMAS through the Polar Ice Center, a group of dedicated investigators that conducts interdisciplinary research on the oceanography, climatology, meteorology, biology and ecology of the ice-covered regions on Earth and elsewhere in the solar system.

Through the perfect dance of loss and hauntingly beautiful music merged with pending disaster, Robinson has brought home a message in this video that we all need to heed: "Survival is not compulsory, nor a God given right. It requires effort, investment and cooperation."

Are we listening yet?

Dorsi Diaz is a freelance writer and art educator living in the San Francisco Bay Area. Dorsi's passion is to help adults and children unlock their creativity and imagination and to also spread the word about the effects of world-wide climate change - follow Dorsi Diaz on Twitter

Below, the Arctic Death Spiral, another visualization of the PIOMAS data by Andy Lee Robinson. 

Andy's Arctic Death Spiral - update incl May 2013 - latest version at http://haveland.com/share/arctic-death-spiral.png


Below, Andy's Arctic Death Spiral video, with the sea ice volume data controlling spectral harmonics.




Added below is a video of another Arctic Death Spiral, accompanied by Chopin's 'Funeral March'. This work is not by Andy, it's from reric.org by R. Eric Collins.



Monday, August 13, 2012

Getting the picture

Have a look at the picture below. It shows a graph based on data calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) developed at the Applied Physics Laboratory/Polar Science Center at the University of Washington.
image from arctische pinguin - click to enlarge
The PIOMAS data for the annual minimum values are the black dots. The trend (in red) is added by Wipneus and points at 2015 as the year when ice volume will reach zero. Note that the red line points at the start of the year 2015. The minimum in September 2014 will be already be close to zero, with perhaps a few hundred cubic km remaining just north of Greenland and Canada.
image from arctische pinguin - click to enlarge
Above image, again based on PIOMAS data, shows trends added by Wipneus for each month of the year. The black line shows that the average for the month September looks set to reach zero a few months into the year 2015, while the average for October (purple line) will reach zero before the start of the year 2016. Similarly, the average for August (red line) looks set to reach zero before the start of the year 2016.

In conclusion, it looks like there will be no sea ice from August 2015 through to October 2015, while a further three months look set to reach zero in 2017, 2018 and 2019 (respectively July, November and June). Before the start of the year 2020, in other words, there will be zero sea ice for the six months from June through to November.

Actually, events may unfold even more rapidly. As the ice gets thinner, it becomes more prone to break up if there are storms. At the same time, the frequency and intensity of storms looks set to increase as temperatures rise and as there will be more open water in the Arctic Ocean.


Above photo features Peter Wadhams, professor of Ocean Physics, and Head of the Polar Ocean Physics Group in the Department of Applied Mathematics and Theoretical Physics, University of Cambridge. Professor Wadhams has been measuring the sea ice in the Arctic for the 40 years, getting underneath the ice with the assistance of submarines, collecting ice thickness data and monitoring the thinning of the ice. This enabled 1970s data and 1980s data to be compared, which showed that the ice had thinned by about 15%. Satellite measurements only started in 1979.

Thinning of the ice is only one of the problems. "The next stage will be a collapse," Professor Wadhams warns, "where the winter growth is more than offset by the summer melt. If we look at the volume of ice that is present in the summer, the trend is so rapidly downwards that this collapse might happen within three or four years."

Apart from melting, strong winds can also influence sea ice extent, as happened in 2007 when much ice was driven across the Arctic Ocean by southerly winds. The fact that this occurred can only lead us to conclude that this could happen again. Natural variability offers no reason to rule out such a collapse, since natural variability works both ways, it could bring about such a collapse either earlier or later than models indicate.

In fact, the thinner the sea ice gets, the more likely an early collapse is to occur. It is accepted science that global warming will increase the intensity of extreme weather events, so more heavy winds and more intense storms can be expected to increasingly break up the remaining ice, both mechanically and by enhancing ocean heat transfer to the under-ice surface.

Recent events in the Arctic underline this warning. A huge cyclone battered the sea ice early August 2012. The image below, from The Cryosphere Today, shows a retreat in sea ice area to 3.09958 million km2 on the 222nd day of 2012, down from 3.91533 million km2 on the 212th day of 2012, i.e. 815,750 km2 less in ten days. Or, more than one-fifth less in just ten days.

Image from  The Cryosphere Today - click to enlarge

Sunday, June 10, 2012

Arctic sea ice volume on track to reach zero around 2015

The image below shows recent data on Arctic sea ice volume, as calculated using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS, Zhang and Rothrock, 2003) developed at the Polar Science Center, Applied Physics Laboratory, University of Washington.



As shown on the images below, by Wipneus and earlier published at the Arctic Sea Ice Blog, sea ice volume loss is on track to reach a minimum of 3000 cubic kilometers this summer.
The recent sea ice volume is in line with the exponential trend calculated by Wipneus that is pointing at zero ice volume around 2015 (image below).

 

Will sea ice collapse in 2014?As described in an earlier post, I believe that a trendline pointing at 2014 fits the data best (image left).

As discussed, some ice may persist close to Greenland for a few years more, since Greenland constitutes a barrier that holds the sea ice in place. Similarly, natural variability could prolong the ice longer than expected.

However, such arguments offer no reason to rule out an imminent collapse of the sea ice, since natural variability works both ways, it could bring about such a collapse either earlier or later than models indicate.

In fact, the thinner the sea ice gets, the more likely an early collapse is to occur. There is robust evidence that global warming will increase the intensity of extreme weather events, so more heavy winds and more intense storms can be expected to increasingly break up the remaining ice in future, driving the smaller parts out of the Arctic Ocean more easily. Much of the sea ice loss already occurs due to sea ice moving along the edges of Greenland into the Atlantic Ocean.

Could you think of any reason why Arctic sea ice would NOT collapse in 2014?