Arctic Ice Data And Stats.

[Guest]

ARCTIC 2M SURFACE TEMPERATURES AND SEA SURFACE TEMPERATURE UPDATE

I am somewhat confused.  I see that there is another Arctic thread which has just been opened "Arctic Sea Ice - The Refreeze 2018/19".  These are extremely similar threads and surely will only serve to confuse members?  This post is all about the re-freeze but also looks at earlier years and is equally about Arctic ice data and Stats.  As I frequently wish to cross post on two forums I need some continuity so that I can refer back to earlier posts to avoid repeating certain charts. I started an Arctic thread on a US forum and we only have a single Arctic thread there. What are others' opinions on this?  I'll happily post on this thread, especially as it seems to run indefinitely which is great for comparisons to early events/seasons.

Latest Ice Extent:

Unfortunately, before I get into my temperature analysis, I can only bring some more very worrying news. Yesterday, the Arctic Sea ice extent has just become the lowest on record for this time of year.  I reported on minimum ice extent in my post on October 14th. In September,  2018 ended up as the 6th lowest on record, roughly equal to 2008 and only above (in the order of lowest first) 2012, 2016,  2015, 2017 and 2013.  2012 was the record low year with a much lower minimum ice extent than in any other year. 2012 did start to see a fast recovery from mid September which accelerated further during October. This year, just like in 2016 has seen a really late and very slow recovery.

            

Although recovery has accelerated during the last 10 days, the pace has been slower than in 2012. On 19th October, 2018 has crossed over and is now below 2012 as can be seen in the chart above. 

Just a reminder of the position on October 7th by way of comparison (the date of the last main NSIDC report and update).

The only piece of better news (or less bad news) is the the ice sheet is now finally building across towards north east Siberia and the continuous expanse of open water on the whole Eurasian side of the Arctic looks set to be closed within a few days. Given reasonably favourable recovery conditions, this should help to enhance faster re-freezing as the surface currents effectively become dammed.  

2m Surface Temperatures:

There are currently wide areas of the Arctic close to or even slightly above 0c. 

This chart shows the mean 2m surface temperature anomalies for this month to date. Those mid-brown colours in the high Arctic and around the pole are some 12c to 16c above average - that is for all of October and is quite exceptional. Much of the Arctic region is running at well over 4c above the mean.  Greenland and N America are below average and just a small part of southern Siberia is too.

October 2017 for comparison - warmer than average but not nearly as warm as this October.

Finally 2012. Some very warm anomalies but nowhere near as extensive as in 2018.

As I'll be making reference to some of the seas below, here's a map to remind those who are not familiar with the Arctic region.

Sea Surface Temperatures:

The -1.5c temperature and below (purple colours) are key as this is the level where sea water will start to freeze.  Note the wide area which is still running closer to 0c (the dark blue colours). Even more of a concern are the vast expanses of water with SSTs well above freezing. We have become used to that in recent years on the Atlantic side particularly in the Barents and Kara Seas.  This year the Pacific side also has worryingly high SSTs. The Bering and even the Chukchi Seas are also running well above 0c. This is a legacy of the very active west Pacific typhoon season which have pumped up some very warm surface waters unusually far north. 

Now the SST anomalies. Those dark brown colours are +ve anomalies in excess of 6c and the olive patches (such as south west of the Svalbard islands) are anomalies exceeding +8c. 

The only less bad news is that the North Atlantic is running below normal. 

That Atlantic cold pool for the last couple of years was mostly south west of Greenland. This year while the mid latitudes of the N Hem saw widespread record summer heat, further north it was much colder than usual. Iceland had one of its coldest summers for many years. Although SSTs briefly recovered they are trending down again.  Right now, almost the whole of the North Atlantic from 50N to 65N is running below average. This should mean that with relatively less warm Atlantic SSTs, the Atlantic side of the Arctic may get a little respite moving into this winter. Sadly, it will take a lot more than this to lower those abnormally high Arctic SSTs which are partly a long term legacy from the 2015/16 super El Nino when the almost relentless, powerful jet stream pushed warmer waters right up to the edge of the ice sheet for prolonged period.   

Overall, things are looking pretty grim. When we analyse those 2m surface temperature and SST anomalies it is hardly surprising that the refreeze is really struggling.  David 

[Guest]

GREENLAND REPORT (1)

I produced this post on my Arctic thread on a US weather forum today and feel that it's worth copying on to NetWx.

I have been intending to do a post on Greenland for some time. This is a vitally important part of the Arctic region and contains a high proportion of the permanent land ice in the Arctic. Some of the news is not nearly as bad as one might believe. 

In this first report I'll look at the current ice extent and temperatures in Greenland and put these into context.  I shall also explore some longer term figures.  I shall begin with a few geographical, geological and ice sheet facts. This introductory post is necessarily a long one but my future Greenland posts and updates can refer back to this one as a reference point and can be much shorter!

Greenland Geography:

In this part I am pulling together some of the fascinating facts about Greenland's geography and geology and I draw heavily on data, maps, charts and photographs from Wikipedia. Greenland has an area of 836,330 square miles. To put this into context, the US is about 5 times bigger than Greenland but Greenland is 9 times larger that the whole of the UK.

  

The island has 27,554 miles of coastline. It stretches for 1,656 miles from north to south between its longest points and 750 miles from east to west at its widest points. Permanent ice still covers most of the landmass at the time of the summer minimum extent. The ice sheet has an area of about 660,000 square miles, a length of 1,500 miles and a width of 680 miles.  The average ice sheet thickness is 6,600 ft to 9,800 ft.  Much more on this, seasonal variations and longer term trends below. 

 

The country looks much larger than it actually is on most global maps due to flattening out the earth's surface. The map above moves Greenland alongside Africa for a true comparison. 

 

Greenland is very mountainous.  If we removed the ice, the island would like it does in the map above. The highest point is Gunnbjorn Fjeld at 12,119 ft and this is the highest peak inside the whole of the Arctic circle - it's located in the east at 68.6N and 29.5W. There are high plateau regions in much of the south and the east and also in parts of the west and, to a lesser extent, in the north. Much of the eastern plateau is well over 2,000 m (6,500 ft).  A few of the models (such as JMA) do not adjust mean pressure to sea level equivalents and as pressure is much higher over the elevated plateau this "can" give a very false impression with MSLP sometimes overstated by well over 25mb! 

  

This photograph from the eastern coast shows how the high mountains and the plateau extend right up to the sea for long distances.

Parts of the centre of Greenland, particularly further north are close to or below sea level as can be seen in the "iceless" map above.  Surface lakes have been discovered as well as unfrozen water under deep layers of ice. The Greenland ice sheet is actually very mobile. There is some very dense ice in the thickest parts of the ice sheet.  Snowfall accumulations in the centre is steadily compressed into ice that flows towards the outer margins just as in Antarctica or with other larger snow fields and glaciers. Very close to the edges, the ice melts in the summer half of the year and also breaks off into icebergs. Snow deposited on the central parts of the ice sheet is gradually compressed into ice.  To give an idea of this compression, new snow falling onto the ice sheet has a density of around 60 kilograms per cubic metre while water has a density of 1,000 kilograms per cubic metre. In the central part of the ice sheet the temperature never rises above freezing so the snow never melts (not even with Arctic amplification and warming). Instead, it becomes buried under new layers of snow, with the weight of the new snow increasingly compressing the layers below and steadily becoming denser.  Once the density of the snow reaches 830 kilograms per cubic metre, which is around 80 metres deep, all the air passages between the crystals are sealed off so the only air that exists is in trapped bubbles. As the depth increases the density of the ice increases further and at 917 kilograms per cubic metre air bubbles are compressed. At this stage the ice has become glacial ice and it cannot be compressed anymore.

Scientists have been conducting much research into the Greenland ice sheet.  Core samples and sophisticated techniques are helping them put together accurate temperature records going back over 130,000 years!  We can look into all this fascinating and very important research on this thread. Now I'll move on to the current conditions:

Current Greenland Ice Extent, Summer Melting and Temperatures:

In this section I shall rely heavily on the latest NSIDC data.

  

This time of year the sheet sheet is normally expanding with little or no melt.  The white area is where there is no melt and red areas (none now) where there is melting in progress. The grey areas nearer the coast are beyond the main (thicker) ice sheet but are not ice free and in fact they are all snow covered right now. NSIDC explain: "The satellite sensor’s resolution is not fine enough to distinguish ice from land when a pixel overlaps the coast."

 

This map shows the cumulative melts days for this year to date.  The white areas are zero.  Around the margins the reds and pinks tell us that there has been some net melting on 60 to 80 days this year. There are one or two isolated tiny brown areas with around 100 melt days. 

 

This chart puts 2018 into context with 2018 (red) compared to the 1981-2010 30 year mean (blue), the last 25 years average (1994-2018) in dark grey and the last 10 years (2009 to 2018) in light grey. The melt season has seen large fluctuations during the summer but was well above average in late July. The melt season, however, came to an abrupt and early finish in mid-August.  Here's the reason:

  

While the Arctic Ocean and almost all the Eurasian Arctic have seen some exceptionally high surface temperatures with very strong +ve anomalies, the Canadian Arctic and almost all of Greenland have seen much lower surface temperatures with strong -ve anomalies.  The Greenland average anomaly for this month to date is running at -1.65c but some central and western parts have -ve anomalies exceeding -5c. and widely below -3c. The September average anomaly for all of Greenland was -0.11c.  These values are in such stark contrast to those elsewhere in the Arctic region, particularly around the North Pole. These -ve anomalies represent temperatures well below freezing: 

  

Widely below -20c and much of the central eastern plateau is below -40c. 

  

I have produced this interactive chart.  It is is available for the entire satellite imagery series from 1979 to date on this link:

https://nsidc.org/greenland-today/greenland-surface-melt-extent-interactive-chart/

I included 2018 (blue line), 2017 (green line), 2012 (yellow line) and 1980 (black line) and compare all these to the 30 year mean, 25 year spread and 10 year spread.  It's a somewhat busy chart but I wanted to show the most recent years, the record high melt year of 2012 and the lowest melt year of 1980 for the whole 1979 to 2018 period compared to the longer term averages. Interestingly 2018 had a late start as well as an early finish - so a very short melt season but with some periods of strong melting in mid-summer.  2017 had a longer melt season but with much lower melts rates for much of the time.  2012 completely dwarfs the other years with some exceptional melt rates.  The early end to the 2018 melt season is unusual and actually ahead (below) the 30 year mean and well ahead of the decadal average. This is very much due to circulation patterns. It can hardly be down to low solar activity when much of the Arctic region is so warm right now.  

  

This chart shows the model results for the Greenland Ice Sheet snowfall and melt runoff since 1960. The model (MAR 3.9) was run using input from National Centers for Environmental Prediction (NCEP) weather reanalysis data. The surface mass balance (SMB) refers to the net difference between snowfall input and meltwater runoff, or evaporation, loss. The bars show the relative difference from the 1981 to 2010 reference period of observations and modeling. 

Not only did 2018 have a short melt season (the yellow bar) which overall was actually below the 58 year mean (the 0 axis), due to its brevity but it has seen the second highest snowfall year to date (the red bar) for the entire period and with 2 more full months to go, it's likely to smash the 1972 record - so a truly exceptional year and some very good news for a change but there is a slight "possible" downside (see my quote from the NSIDC report below). The surface mass balance (blue bar) has seen a lot of negative years since 2006 mostly due to the very high melt rates. 2018 to date has the fourth equal best SMB since 1960, the highest since 1996 and may well end up in second place behind 1972 (no more melting and further snowfall still to come).

This from the most recent NSIDC report on Greenland: 

...." exceptional winter snow accumulation and heavy, summer snowfall, drove the net snow input mass to 130 billion tons above the 1981 to 2010 average. This was followed by a near-average melt and runoff period, resulting in a large net mass gain for the ice sheet in 2018 of 150 billion tons. This is the largest net gain from snowfall since 1996, and the highest snowfall since 1972. However, several major glaciers now flow significantly faster than in these earlier years. The net change in mass of the ice sheet overall, including this higher discharge of ice directly into the ocean, is not clear at this point but may be a smaller loss or even a small gain. This is similar to our assessment for 2017, and in sharp contrast to the conditions for the preceding decade. Persistent winds from the northeast triggered high snowfall for 2017 to 2018 along the eastern Greenland coast. These winds blew across open ocean areas allowing the atmosphere to entrain moisture and deposit it as heavy snowfall on the ice sheet....."

  

The top graph shows the 2018 reflectivity trend for the entire Greenland Ice Sheet through September 15, and four reference years: 2000, 2010, 2012, and 2017. The grey band represents the 5-to-95 percent range for the 2000 to 2009 reference period. The maps below show average monthly albedo, or solar reflectivity, for July 2018, on the left, and August 2018, on the right.

 

In Antarctica the vast white ice sheet there reflects over 85% of the sun's rays back into space during their summer half of the year and this is known as the albedo effect (I described this process on this thread in a post further up this page). This protects the ice from melting and preserves it. The Greenland ice sheet also has a strong but lesser albedo effect. The top chart compares 2018 (in purple) to recent years. Compared to the 2000-09 average (the grey spread) it's not surprising to see 2018 near the top.  All that summer snowfall and increased white surfaces produced a far higher albedo than in many recent years. 2012 saw the lowest values.  This from the NSIDC report:

 

...."High winter and spring snowfall, and a moderate initial pace of melting, resulted in a more reflective (higher albedo) surface for the ice sheet than in past summers. Since bright, fresh snow blanketed areas that were once darker, such as dirty snow or bare ice, July’s average albedo for the ice sheet was 5 to 9 percent above the 2000 to 2009 reference period. Wet snow also has a darker surface, or lower albedo. Increased surface melting, above-average temperatures, and the three spikes in melting, August’s albedo decreased to more average values. However, the albedo along the western coast remained above average....."

 

Since August we have seen the early end to the melt season, those below average surface temps (well below this month) and continued above average snowfall. It's highly likely that the albedo has been very strong during the last few weeks. 

  

This chart shows the thickness of the Greenland ice sheet.  As earlier, the satellite sensory equipment does not pick up very well the areas beyond the continuous thick ice sheet.  Those coastal regions are currently ice and/or snow covered.  So, although Greenland extends south of the Arctic Circle towards the Atlantic Ocean and is exposed to the jet stream and the Gulf Stream and takes a battering from passing depressions and Atlantic storms for long periods every winter, it's generally high elevation helps it to retain much of its ice sheet and produces some huge snowfalls. It has been impacted by global warming and climate change but, so far at least, not nearly to the same extent as the polar regions and the Arctic Ocean. Some of the hyped reports have been very misleading.  I intend to do a post on global ice extent quite soon and this will show the importance of the Greenland ice sheet and more especially the Antarctica ice sheet in, at least, slowing down the impacts of overall ice loss through global warming.  We also need to examine the rate of decline and thoroughly analyse the reasons, ignoring both extremes of the climate change debate to get at the facts.  David   

 

 

Edited October 25, 2018 by Guest

[Midlands Ice Age]

On ‎21‎/‎10‎/‎2018 at 01:12, Bring Back1962-63 said:

ARCTIC 2M SURFACE TEMPERATURES AND SEA SURFACE TEMPERATURE UPDATE

I am somewhat confused.  I see that there is another Arctic thread which has just been opened "Arctic Sea Ice - The Refreeze 2018/19".  These are extremely similar threads and surely will only serve to confuse members?  This post is all about the re-freeze but also looks at earlier years and is equally about Arctic ice data and Stats.  As I frequently wish to cross post on two forums I need some continuity so that I can refer back to earlier posts to avoid repeating certain charts. I started an Arctic thread on a US forum and we only have a single Arctic thread there. What are others' opinions on this?  I'll happily post on this thread, especially as it seems to run indefinitely which is great for comparisons to early events/seasons.

Latest Ice Extent:

Unfortunately, before I get into my temperature analysis, I can only bring some more very worrying news. Yesterday, the Arctic Sea ice extent has just become the lowest on record for this time of year.  I reported on minimum ice extent in my post on October 14th. In September,  2018 ended up as the 6th lowest on record, roughly equal to 2008 and only above (in the order of lowest first) 2012, 2016,  2015, 2017 and 2013.  2012 was the record low year with a much lower minimum ice extent than in any other year. 2012 did start to see a fast recovery from mid September which accelerated further during October. This year, just like in 2016 has seen a really late and very slow recovery.

            

Although recovery has accelerated during the last 10 days, the pace has been slower than in 2012. On 19th October, 2018 has crossed over and is now below 2012 as can be seen in the chart above. 

Just a reminder of the position on October 7th by way of comparison (the date of the last main NSIDC report and update).

The only piece of better news (or less bad news) is the the ice sheet is now finally building across towards north east Siberia and the continuous expanse of open water on the whole Eurasian side of the Arctic looks set to be closed within a few days. Given reasonably favourable recovery conditions, this should help to enhance faster re-freezing as the surface currents effectively become dammed.  

2m Surface Temperatures:

There are currently wide areas of the Arctic close to or even slightly above 0c. 

This chart shows the mean 2m surface temperature anomalies for this month to date. Those mid-brown colours in the high Arctic and around the pole are some 12c to 16c above average - that is for all of October and is quite exceptional. Much of the Arctic region is running at well over 4c above the mean.  Greenland and N America are below average and just a small part of southern Siberia is too.

October 2017 for comparison - warmer than average but not nearly as warm as this October.

Finally 2012. Some very warm anomalies but nowhere near as extensive as in 2018.

As I'll be making reference to some of the seas below, here's a map to remind those who are not familiar with the Arctic region.

Sea Surface Temperatures:

The -1.5c temperature and below (purple colours) are key as this is the level where sea water will start to freeze.  Note the wide area which is still running closer to 0c (the dark blue colours). Even more of a concern are the vast expanses of water with SSTs well above freezing. We have become used to that in recent years on the Atlantic side particularly in the Barents and Kara Seas.  This year the Pacific side also has worryingly high SSTs. The Bering and even the Chukchi Seas are also running well above 0c. This is a legacy of the very active west Pacific typhoon season which have pumped up some very warm surface waters unusually far north. 

Now the SST anomalies. Those dark brown colours are +ve anomalies in excess of 6c and the olive patches (such as south west of the Svalbard islands) are anomalies exceeding +8c. 

The only less bad news is that the North Atlantic is running below normal. 

That Atlantic cold pool for the last couple of years was mostly south west of Greenland. This year while the mid latitudes of the N Hem saw widespread record summer heat, further north it was much colder than usual. Iceland had one of its coldest summers for many years. Although SSTs briefly recovered they are trending down again.  Right now, almost the whole of the North Atlantic from 50N to 65N is running below average. This should mean that with relatively less warm Atlantic SSTs, the Atlantic side of the Arctic may get a little respite moving into this winter. Sadly, it will take a lot more than this to lower those abnormally high Arctic SSTs which are partly a long term legacy from the 2015/16 super El Nino when the almost relentless, powerful jet stream pushed warmer waters right up to the edge of the ice sheet for prolonged period.   

Overall, things are looking pretty grim. When we analyse those 2m surface temperature and SST anomalies it is hardly surprising that the refreeze is really struggling.  David 

David..

Thanks for this brilliant report.

It was  for last Sunday (21/10/2018)…  and 4 days later  things have changed a  bit.

Your final summarising paragraph, I feel needs to be 'brightened up' slightly.

The last 4 days have seen this year playing 'catch up' bigtime with flash freezes in the key Russian side areas of Laptev and the ESS. Also there are considerable signs that Kara is now joining in (next door).

Ice extent is now well above 2016, at this point, and within the next few days,  with Hudson and Baffin (early) also going into rapid ice build mode, we could well see 2018 back into the pack once again.

To give you an idea, JAXA has recorded Arctic sea ice gains of 800K Km2 (Oct 21st 6136K Km2 and today the 25th is 6933K Km2)  in the last 4 days since your report. That is one of the quickest gains on record.    Maisie  has recorded even more.

Note this post is not intended to be bullish, but to point out that after the very slow start this year, a rapid ice build up was to be  expected, and apparently is,  occurring.

The current situation, with a large northerly outbreak into the UK and Europe, will have affects into the Arctic.  It will be interesting to monitor the Arctic ice extents for the ice impacts over the next few days.   

 

MIA   

[Guest]

11 hours ago, Midlands Ice Age said:

David..

Thanks for this brilliant report.

It was  for last Sunday (21/10/2018)…  and 4 days later  things have changed a  bit.

Your final summarising paragraph, I feel needs to be 'brightened up' slightly.

The last 4 days have seen this year playing 'catch up' bigtime with flash freezes in the key Russian side areas of Laptev and the ESS. Also there are considerable signs that Kara is now joining in (next door).

Ice extent is now well above 2016, at this point, and within the next few days,  with Hudson and Baffin (early) also going into rapid ice build mode, we could well see 2018 back into the pack once again.

To give you an idea, JAXA has recorded Arctic sea ice gains of 800K Km2 (Oct 21st 6136K Km2 and today the 25th is 6933K Km2)  in the last 4 days since your report. That is one of the quickest gains on record.    Maisie  has recorded even more.

Note this post is not intended to be bullish, but to point out that after the very slow start this year, a rapid ice build up was to be  expected, and apparently is,  occurring.

The current situation, with a large northerly outbreak into the UK and Europe, will have affects into the Arctic.  It will be interesting to monitor the Arctic ice extents for the ice impacts over the next few days.   

 

MIA   

ARCTIC ICE EXTENT UPDATE - SOME RECENT PROGRESS 

Thank you for your kind words MIA. They say a week is a long time in politics - well 4 days is a long time in the Arctic re-freeze season!  I do not see any new posts on the "Arctic Sea Ice - The Refreeze 2018/19" thread (or on the other 3 Arctic, Ice and Snow related threads which I shall mostly ignore from now on as one ongoing thread is more than enough for a specialist topic like this. So I'll always stick to this long term trusted thread (apart from using the Antarctica thread from time to time). I'll do a quick update and also make a comparison to 2016 which is likely to remain the competing year during the next few weeks for the unfortunate title of the lowest ever ice extent for the time of year. I will be cross-posting this update onto the US forum Arctic thread and I'll copy your comments too, so that it all makes sense!  it's actually easier to cross- post the other way around (which I've done before and will do in future) as I have no editing time limits on the US forum but longer posts are really restricted on NetWx and I often do not have enough time to make corrections with typos, links and charts etc..

2018 and 2016 Comparison:

Exact comparisons are always a nightmare as the data relating to the extent of 15% ice through to continuous pack ice is necessarily approximate. Furthermore, the archive records on NSIDC are for their monthly reports, not daily charts but "some" of this is available on other sites. From the satellite data whole Northern hemisphere ice extent is calculated, then the greater Arctic region and then the main continuous ice sheet as well as a data set for each individual sea. How these figures are presented can make quite a difference. I'll start with the JAXA data that you refer: 

              October 24th, 2018 (area)                     October 24th, 2018 (extent)     

     

I could say spot the difference! It is a very small one but the first chart shows "Sea Ice Area" and the second chart shows "Sea ice Extent". This is what they say:

Ice extent is the cumulative area of all polar grid cells of the Northern Hemisphere that have at least 15% sea ice concentration, using the NORSEX algorithm. Ice area is the sum of the grid cell areas multiplied by the ice concentration for all cells with ice concentrations of at least 15%. Ice extent and ice area are calculated for a grid resolution of 25 km. The difference between extent and area for our data is always positive. This difference represents the area of the open water in the pixels partly covered by ice (i.e. ice concentration less than 100%). In other words, ice area takes into account that there is a fraction of open water in pixels with ice concentration above 15% and below 100%". Ice extent does not include this effect and gives therefore a higher number of square kms than ice area does.

If we move away from the precision of the two calculating methods and just focus on the charts we can see what has happened in the last couple of weeks. We should bear in mind that October and November usually see the faster rate of ice extent recovery with just a few exceptions. Quite often seasons with a slow start or coming from a very low minimum extent need to play "catch up" and we see even faster recoveries.  2012 saw that record low extent but by mid October it was recovering so quickly that both 2016 and 2018 have fallen behind. 2016 and 2018 have crossed over 3 times since the re-freeze commenced and during the last week or so have been running almost neck and neck.  As they are competing for the worst ever position we can track the differences. In the first "area" chart for Wednesday, I would say that it's a tie. In the second "extent" chart, you are right to say that 2018 has once again edged ahead. As you say, the strong recovery continued yesterday and into today. There is a fascinating array of data, charts and links on the JAXA site as well as on some other sites and there is a slightly larger spread of differences between the two years (in both directions).  I just went into this detail to make the point that we can only ever take a close approximation at best.  One thing for certain is that both 2016 and 2018 compared to other years have the lowest extent on record for late October.  Let's look at the trend and what might happen during the next few weeks.   

             October 12th, 2018                                October 19th, 2018                              October 25th, 2018                             October 31st, 2016                         

                         

Firstly, we can see the rapid recovery in 2018 during the last 2 weeks. It was important for the ice to bridge across from the main ice sheet towards Russia and Siberia shutting off the open water surface flow. . Now, I cannot find a chart for October 24th or 25th 2016.  I show the one in the November 2016 monthly report and the chart is at October month end. This is 6 days later - so not ideal. Then i found this chart on Zach Labe's site:

              October 27th, 2016               

Then, if we look at the earlier JAXA chart, 2016 had a pause during the last few days of October with the rate of recovery very small indeed and October 27th was just before that month end stall. Now, I believe that we are pretty likely to see a 2018 stall too.  Let's look at the 2M surface temperatures and SST charts for both years. 

              1400 October 26th, 2018                                                           1400  October 26th, 2016                                

                                      

Surface temperatures were running well above average in 2016 but not as high as in 2018 in the high Arctic, closer to the Pole.  

                1400 October 26th, 2018                                                        1400  October 26th, 2016           

                                       

Since the 2015/16 super El Nino, SSTs in the open waters of the Arctic have been running very much above average. The distribution across the whole Arctic Ocean is surprisingly similar. Circulation patterns, wind direction and strength also make a difference (not shown). The high SSTs with large areas well above the critical level of -1.5c (where sea water starts to freeze) were prevailing in both years. With this and the high 2M surfaces temperatures right now (even higher than in 2016), this may well stall or slow the re-freeze for at least a short period.  Unless the surface temps fall back quickly to well below freezing, the 2018 ice build up may continue at similar rates to 2016. The Siberian side is the warmest and that's where the ice extent is so far below average.  The Canadian Arctic and Greenland are colder than normal right now and have been for a few weeks and ice accumulation in that part of the Arctic ocean will continue apace.  We need to monitor the other side and especially those northern Russian and northern Siberian temperatures. Things may well turn around during November with a sustained faster recovery again.

Finally, in my next Arctic post (next week) I'll be addressing your previous comments and query wrt the longer term, older ice. I have pulled together the latest figures and they do not make pretty reading. David  

 

Edited October 26, 2018 by Guest

[Guest]

THE VERY WORRYING DECLINE IN OLDER ARCTIC ICE - THE LATEST POSITION

Arctic sea ice minimum extent usually occurs during September.  This year it was reached quite late on September 23rd. 2018 tied with 2008 seeing the sixth lowest minimum on record.  

This as well as the very slow rate recovery have been discussed in recent posts on here.  Although these extremely low levels of minimum ice extent are bad enough, even more worrying is the decline of older or multiyear ice. During the winter season new ice that forms over open water can grow up to 1.5 to 2 meters thick. This "first-year" ice is highly likely to melt the following summer. Any ice that survives the summer melt can grow at least twice as thick as first-year ice. The older the ice, the thicker it is likely to be and the more likely that it is likely to survive the next and future melt seasons.

The chart below shows the distribution and age of the ice that survived the 2018 summer melt season. Week 38 end on September 23rd, when minimum ice was reached. 

Much of the surviving ice was 1 to 2 years old,rather less was 3 years old, a tiny amount was 4 years old and there was very little 5 years or older ice remaining. The next chart really puts this into context.

During the 1980s almost half of the ice remaining was more than 5 years old. This has declined pretty steadily ever since and now there is practically no 5 year + ice remaining.  There is even less 4 year old ice. 3 year old ice has been more variable and only declined slightly.  2 year old ice was remained fairly constant as has 1 year old ice but remember this is at the expense of older ice. Overall minimum ice extent has fallen from around 6.6 million square kilometers in 1985 to around 3.6 million in 2018. Multiyear ice (2 years and older) has fallen from around 4.4 million in 1985 to just under 2 million in 2018.  The 5 year and older has has declined from around  2.3 million in 1985 to under 0.1 million (actually 94,000) square kilometers (36,000 square miles) this year. 

This chart shows us the thickness of the current ice sheet in meters.  The ice that formed in the last few days on the Siberian and Russian side of the Arctic is just a few inches thick - up to 0.25m thick (the mauve colour). The ice is progressive thick the further west one goes. Much of this from the pole towards the Canadian Arctic is 2 to 3 meters thick. There is some that is over 3m thick and tiny patches of 4m or thicker ice.  Compare this to the average thickness of the Antarctica and Greenland ice sheets which are 2,000 to 3,000m. Sea ice is much thinner than land ice but what there is in the Arctic, is generally thinning and melting. 

David

EDIT:  Hi MIA - @Midlands Ice Age, I think that this post covers your earlier comments on this thread about the decline in the older ice.  I was going to do this update anyway but we are very much on the same "concerned" wavelength about this.  David  

[Seasonality]

@Bring Back1962-63 thank you for these excellent updates. The situation in the Arctic has got beyond the stage where it it should merely ring alarm bells but is now instead sounding deafening klaxons for the state of the planet. The data does not lie.

[Guest]

ARCTIC UPDATE - MIXED NEWS ON ICE EXTENT, 2M SURFACE TEMPERATURES AND SSTS

Please note that I am cross-posting this from the US forum where I posted it several hours ago.  I'll leave it unedited but over 99% equally applies here in the UK.

Well first of all hat's off to Dave @Midllands Ice Age (UK).  Rather than a pause, the re-freeze has actually continued at an impressive rate. Nevertheless, there are still various concerns.  I'll comment below each chart.

  

Please refer to the Arctic map in my introductory post to this thread which shows all the Arctic regions and seas. The overall Arctic sea ice extent has recovered strongly but is still below average in many parts, especially in the Bering Sea (almost no ice), the Chukchi Sea, the Barents Sea and part of the Kara Sea.  The exceptions are in the Canadian Arctic (fully frozen) and Baffin Bay (west of Greenland) as well as in Hudson Bay and the Gulf of St Lawrence which are starting to freeze over rather earlier than in many recent years (although 2017 was an early re-freeze for Hudson Bay too). 

  

Much of the main ice sheet is approaching 90% to 100% ice concentration.

  

This map shows us the different ages of the ice.  The brown area is the ice that has survived for at least 1 year. Green shows the thickest "new" ice, pink is medium thickness and dark blue is the thinnest, often referred to as "nilas".  Here's a link to the types of new ice, how it forms and the terms used: 

 https://nsidc.org/cryosphere/seaice/characteristics/formation.html

  
This chart is from that part of the NSIDC site.

  

This map shows how quickly ice extent recovered during October and this continued into November.

 

It's normal for there to be pauses or setbacks in the rate of recovery during the main re-freeze season. So far, 2018 has seen the fastest continuous recovery since early October compared to any of the previous 7 years.  Only 2012, which saw the record minimum extent, comes close to matching 2018. 

 

Unfortunately, all these recent years are below or well below the 1979 to 2006 mean.

  

The good news is that much of the Arctic has cooled down significantly in the last 2 weeks. 

  

The Canadian Arctic and Greenland have been persistently colder than most of the rest of the Arctic region. Many parts of Siberia and northern Russia have cooled off more than forecast (just 2 weeks ago) which is probably one of the main reasons why the re-freeze has continued apace.

 

The 2m surface temp anomalies for this month to date are actually not as bad as those at the time I last posted this chart (in my post on October 20th on page 2 of this thread). Back then the Arctic Ocean was running at +4.012c; the whole of the Arctic region (66N-90N) was at +3.532c; the sub Arctic and Arctic (60N-90N) was at +2.709c and only Greenland was colder at -1.19c. 

  

This chart shows the predicted anomalies for T+!68 or a week from now. The cooling trend is expected to continue over almost all the Arctic and sub Arctic region and over the ocean with temps returning to closer to normal with only Greenland becoming much warmer.  Given that temps there will be in the -20c to -40c range, a + 4.45c anomaly is not too much of a concern. This was average regional anomalies but we can see the actual distribution.  North east Canada  is going to become even colder and a slightly colder than average area extends across (and to the south of) the pole and into Russia. Even the very high anomalies in the Bering Sea and Chukchi Sea are expected to ease down to some extent.

  

This chart (from the Zach Labe site) puts the current warmth into context.  There was a period in mid summer when 2018 was running just below the 1958-2002 mean but it has been running at close to record warmth since then. The thin lines cover the range from 1958 to 2016. The predicted further cool off should help to to take 2018 back into the range seen in most of the recent years but still slightly above the long term average.

  

This map shows the Arctic region land mass snow cover anomalies (excluding Greenland which is not shown but actually has near to its highest levels of year to date new snow cover since 1972). The better news here is that most of the regions close to the Arctic Ocean now have close to (grey) or above average (greens) snow cover. Continuous deep snow cover plus generally lower land mass surface temps should assist with the re-freeze but there is one more important ingredient....

  

...SSTs. The areas of open water below 0c have expanded steadily (as they should do approaching winter).  Sea water usually starts to freeze at SSTs below -1.5c depending upon salinity and circulation patterns/wind strength. 

 

The anomalies are actually improving too!  There are still those exceptionally high small areas with anomalies of +6c to +8c and those in the Bering Sea are still very high (but falling).  The overall area of +2c has declined and much of the far North Atlantic is actually below average.  Is this a sign that "if" we see a continuing weaker jet stream and disorganised tropospheric PV plus favourable circulation patterns that SSTs might fall back to less high anomalies?  In a future post, I'll compare these anomalies to those since 2014 (just prior to the super El Nino that pumped in those warm waters) and examine the trend much more closely.

Overall, the news is not nearly as bad as I was expecting - perhaps I should say slightly less worrying than it might have been.  If the re-freeze can continue at a decent rate, it is possible that 2018/19 could turn out to see greater ice extent than in most of the last decade. Things can easily change for the worse again with pauses and setbacks still possible but not for the next week or two at least.  David