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Messages - Stephan

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Antarctica / Re: What's new in Antarctica ?
« on: April 23, 2019, 01:49:47 AM »
The Antarctic Bedrock data was over 10 times harder to align than Greenland. There are hardly any landmarks, just plain white and with fast ice or ice shelfs you don't even know where the land begins. I had to use huge area images to align islands and then cut it down to individual glaciers. The bedrock resolution is just 1km/px as opposed to 0.15km/px for Greenland data.

Arctic sea ice / Re: Latest PIOMAS update (April 2019)
« on: April 16, 2019, 09:17:22 PM »
We should be mindful that stickied threads in particular have a lot of readers who don't actively participate, so churning unrelated discussion in them is a lot of noise for people who specifically just want to see PIOMAS numbers for example.

Antarctica / Re: PIG has calved
« on: April 14, 2019, 06:36:31 PM »
Very late in the season for an optical image but here it is. With a solar elevation of just 1.45 degrees (IIRC that is just three solar disks), the shadowed cracks are shown in exquisite detail.

Notice that the pair of major cracks are getting accompanied by a couple more to the right. This is a new feature, these new ones are not visible on a similar image 9 days older.

Uploaded in the native 15m/pix resolution, you must click the image for the better view.

Science / Re: 2019 CO2 emissions
« on: April 11, 2019, 08:39:20 PM »
I track these things in detail because it is necessary for my PhD,

Good luck with that! :)

If it helps you, there are very accurate emission stats for Germany from Frauenhofer.

All coal plants >>

Percentage renewables >>

Solar and wind >>

Feel free to ask me for translation if necessary.

Science / Re: 2019 CO2 emissions
« on: April 11, 2019, 06:05:14 PM »
Perhaps look in "2019 Mauna Loa CO2 levels"?

Atmospheric levels represent the actions of all sources (natural and anthropogenic) and sinks, and there is a significant amount of natural variation (e.g. La Nina/El Nino). There is also the possibility of feedbacks increasing natural emissions and reducing sinks. So probably not a good link between the two, especially in the short-term.

Coal Usage
Maybe the best proxy is coal usage in China and India, as the increase in coal usage accounted for 70% of the rise in emissions in 2017 and 2018. Forecasts are for 4% growth in India coal usage ongoing and it looks like China is quietly building new coal-fired power stations, so they may not peak for quite a while. Coal consumption statistics are usually quite delayed in reporting though. I ignore any reduction due to increased natural gas usage, as the significantly underreported fugitive methane leaks make it as bad as coal (yes, that means that emissions grew by more than reported in 2018).

Wind and Solar Electricity Generation
Another could be the forecast for the increase in wind and solar electricity generation (not capacity addition which is very misleading due to differing capacity factors) versus the forecast increase in overall electricity generation (growing at about 2.5% per year). If the ratio is greater than 1 (currently less than 0.5) electricity generation is decarbonizing. I ignore hydroelectricity (growth limited and net up-front emissions due to construction and the flooding of vegetation) and the highly questionable bio-fuels (e.g. wood pellets may be just as bad as coal and therefore UK emissions probably did not fall by as much as claimed).

In 2017 humanity utilized approximately 22,000 Terawatt hours of electricity, wind provided 5% of that, and solar 2% of that. Their combined share grew by 1%, which was much less than the 2.6% growth in overall generation. The growth rate would need to treble to start decarbonizing. You can get the data for look-back IRENA (International Renewable Energy Association) and look-forward data from GWEC (Global Wind Energy Council) and Solar Power Europe. Their forecasts for 2019 (which are usually pretty good) point to slowing growth rates in wind and solar, so not decarbonization. Same to 2022.

Internal Combustion Engine Car Fleet
As long as this is growing (as it is rapidly in China and probably soon India, and slowly in the US and Europe) emissions will tend to increase, offset a little by more efficient engines (offset a lot by increases in the size of cars). In 2019 car sales may fall somewhat, but the overall ICE car fleet will continue to grow. Until EV's are a significant share of sales in the USA and Europe this increase will continue. Monthly sales numbers, and EV share, are published monthly. Still too low to reduce the ICE fleet in the USA and EU.

Sorry that its not that simple to do. I track these things in detail because it is necessary for my PhD, it can be quite a pain tracking down accurate (and not misrepresented) data. My take is that, short of a recession, emissions will increase between now and 2022.

Arctic sea ice / Re: Global sea ice area and extent data
« on: April 07, 2019, 10:15:40 AM »
I compared

You are having a way to look at the data in such a unique way, i'm always impressed. Compare on sir!

The consequence of that warming is seen in Banks Island thaw slumps:  Extremes of summer climate trigger thousands of thermokarst landslides in a High Arctic environment
  Antoni G. Lewkowicz & Robert G. Way  -  Nature Communications volume 10, Article number: 1329 (2019)

Retrogressive thaw slumps (RTS) – landslides caused by the melt of ground ice in permafrost – have become more common in the Arctic, but the timing of this recent increase and its links to climate have not been fully established. Here we annually resolve RTS formation and longevity for Banks Island, Canada (70,000 km2) using the Google Earth Engine Timelapse dataset. We describe a 60-fold increase in numbers between 1984 and 2015 as more than 4000 RTS were initiated, primarily following four particularly warm summers. Colour change due to increased turbidity occurred in 288 lakes affected by RTS outflows and sediment accumulated in many valley floors. Modelled RTS initiation rates increased by an order of magnitude between 1906–1985 and 2006–2015, and are projected under RCP4.5 to rise to >10,000 decade−1 after 2075. These results provide additional evidence that ice-rich continuous permafrost terrain can be highly vulnerable to changing summer climate.

paper and pictures at link

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: March 25, 2019, 04:50:36 AM »
(posting a bit sheepishly as I've not commented yet this year  ::))

Here's my customary max season chart showing this year's path relative to the maximum position of previous years.
We were missing you, Hautbois! And your excellent graph too!

Two or three further days losses of this size would push 2019 to #4 in that ranking list.
Let's see how Bering Sea will behave the next days. Its change will probably make the difference...
Near the target! And in just one day!

[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

March 24th, 2019:
     13,839,873 km2, a drop of -71,694 km2.
     2019 is now 5th lowest on record.
     (2012 highlighted)

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: March 24, 2019, 04:09:11 PM »
By the pricking of my thumbs methinks that the Arctic over the next week or may be about to have a melting event. The first two images suggest why. (N.B. the Max image does not mean that on a particular day the Arctic temps will look like that. Rather it is the effect on various parts of the Arctic as warmth and cold move around over the 10 days from today).

So I thought I would past all the Arctic Seas area graphs as at yesterday as a benchmark.

Images 3 & 4 show that the melting is still stalled in the Pacific Gateway.

Greenland and Arctic Circle / Re: How quickly could Greenland melt?
« on: March 17, 2019, 05:07:00 PM »
The channel's name is "Just have a Think". The author will put more videos like this online over the next weeks.

A new video of the same autor: "Greenland Ice Sheet : Is it stable?"

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: March 17, 2019, 11:39:39 AM »
JAXA ARCTIC EXTENT : 14,093,381 km2(March 16, 2019)

- Extent now 178k less than current maximum of 12 March,
- Extent loss 55k, 66 k more than the average gain of 11k on this day.
- Extent is 7th lowest in the satellite record,
- On average (last 10 years) it is 5 days after the maximum (11th March)

The Perils of Projections.
Remaining ice gain in 3  5 4 3 1  zero out of the previous 10 years still gives a resulting maximum of MORE than 14.271 million km2 .

i.e. Extent at 14.271 million km2 on the 12th March is surely the 2019 maximum.

Other Stuff
GFS indicates that overall the Arctic temperature anomaly will gradually rise from around -0.5 degrees to +2.5 over the next 10 days, with the additional warmth mainly from the Pacific side.

Surely this is the day for Neven to make the 2019 Melting Season thread "sticky" ?

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: March 17, 2019, 04:49:38 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

March 16th, 2019:
     14,093,381 km2, a drop of -55,149 km2.
     2019 is now 7th lowest on record.
     (2012 also highlighted)

Arctic sea ice / Re: What's new in the Arctic ?
« on: March 17, 2019, 04:17:14 AM »
Just found this basic information about Arctic Sea Ice changes since 1980s on YouTube

Excellent video Stephan!

Makes me wonder if, apart from the "like" button, we could have a "keep" button, in which we can mark the posts that we really like and we want to have a way to keep them mark for future reference.

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: March 04, 2019, 10:37:36 AM »
I just noticed that 2012 was listed on position 15 in that table - and that later in that year its extent was way below of all other years. I think anything is possible on this date...

2012 had an increase of ice at the beginning of March and it didn't seem that it was going to break any record until the first half of June. I highlight 2012 on this graph (green line).Of course, the 2012 trajectory will look worst if the graph doesn't have the following years, specially 2015-2018.

Addendum: 2nd. graph - 2012 taking out the following years.

Arctic sea ice / Re: The 2019 melting season
« on: March 02, 2019, 11:55:48 PM »
An animation of AMSR2 concentration revealing the recent spread of open water across the southern Chukchi Sea:

Antarctica / Re: Thwaites Glacier Discussion
« on: February 28, 2019, 04:00:18 PM »
This (marked by X) is where the Nathaniel B Palmer is today according to sailwx, S 74°54' W 107°18'. It probably be a while before we hear details of the research there, but the blog posts have a lot of information.
North marked for orientation.

Antarctica / Re: Sea Ice Extent around Antarctica
« on: February 24, 2019, 09:24:45 PM »
NSIDC data from wipneus via file nsidc_ant_nt_detail.txt from
as at 23 February 2019

I was expecting to post the Antarctic sea ice area and extent final graphs for the minimum. But perhaps there is a bit more ice loss to go. Here they are, anyway.

BellingsHausen & Amundsen Sea

Science / Re: 2019 Mauna Loa CO2 levels
« on: February 23, 2019, 07:33:09 PM »
Environmentalists screaming the end of the world is nigh then it turns out to be a bit of variable data just makes the general population react by saying those environmentalists are always crying wolf and are increasingly likely to dismiss environmentalist views. So it is a bad idea and doesn't help the cause.

Totally agree with that.  However the long term trend is up and continues up.  I talk about this on other threads but the point is we are a LONG way from Kyoto, yet the Global annual average continues to climb.

For the last 5 years the global average (based on ESRL NOOA growth stats), show an average of 2.5ppm.  OK 2018 will continue to adjust, the same site had 2015 at over 3ppm at this time of year and then adjusted it down to 2.91.

However the trend is very clear.  This is the first 5 years in the record where no year recorded less than 2ppm growth.  If it were not for 2011, we would be almost at a decade where no year recorded a growth value less than 2ppm.  As it is we'll probably have to wait till 2022 before we see that particular domino fall.  Probably around the time we see the first reported year with 3ppm.

Whilst caution is a very good stance to take, we have had accord and treaty after accord and treaty and the only result has been an acceleration in the growth of CO2 in the atmosphere.

The trend alone is, for some scientists, enough to produce very dire warnings.  Not only is CO2 still growing in the atmosphere, it is growing at an increasing rate.

Just when do you shout fire?  When you smell the smoke or when the flames are licking around your legs?  It is a problem because the population at large doesn't care about smoke and if you wait till the fire has really taken hold, then it's half past too late and nothing truly viable you can do about it.

Antarctica / The Amery Ice Shelf Thread
« on: February 21, 2019, 04:14:14 PM »
Resuming conversation from

New clear Sentinel pics today.

Link >>,B02,B03&maxcc=20&gain=1.0&gamma=1.0&time=2018-08-01%7C2019-02-21&atmFilter=&showDates=false&evalscript=cmV0dXJuIFtCOEEqMSxCMDMqMSxCMDIqMV0%3D

Indeed the big melt pond is now frozen but with pretty blue cracks visible. I wonder if it's melting again. (pic1)

Upstream the melt ponds are still blue. (pic2)

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: February 17, 2019, 05:07:37 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.
February 16th, 2019:
     13,919,453 km2, a drop of -26,050 km2.
     2019 is now 8th lowest on record.

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: February 16, 2019, 02:27:21 PM »
NSIDC Total Area as at 15 February 2019 (5 day trailing average) 12,658,476  km2
Total Area         
 12,658,476    km2      
 164,176    km2   >    2010's average.
 610,283    k   >   2018
-461,506    k   <    2000's average.
Total gain/loss    46    k   gain
Peripheral Seas    20    k   gain
Central Seas__    13    k   gain
Other Seas___    12    k   gain
Peripheral Seas         
Bering _______    11    k   gain
Baffin  Bay____   -0    k   loss
Greenland____    4    k   gain
Barents ______    5    k   gain
CAB Seas         
Beaufort_____    5    k   gain
CAA_________    1    k   gain
East Siberian__   -1    k   loss
Central Arctic_    4    k   gain
Kara_________   -1    k   loss
Laptev_______    0    k   gain
Chukchi______    6    k   gain
Other Seas         
Okhotsk______    5    k   gain
St Lawrence___    2    k   gain
Hudson Bay___    5    k   gain
Area GAIN 46 k, 12 k more than the 2010's average gain of 34k on this day.

Other Stuff
GFS indicates that overall the Arctic temperature anomaly remains between +0 and +3 degrees over the next week or so, with the Pacific side (apart from the Okhotsk) and Baffin bay tending to warmth and the Atlantic front and the Okhotsk tending to cold. The contrast will be extreme at times, as shown in the GFS image for Sunday 17th posted above.

On this day, just about everywhere gaining area.

There's an interesting article from cryosphere looking at using machine learning to track calving faces through SAR products - which has the potential to support the overall tracking of major calvings in greenland and antarctica.

Antarctica / Re: What's new in Antarctica ?
« on: February 07, 2019, 09:28:24 PM »
More of the same…
(Could be in several topics, but maybe this one is the best).

Today’s Earth looks a lot like it did 115,000 years ago. All we’re missing is massive sea level rise.

Arctic sea ice / Re: Latest PIOMAS update (January)
« on: February 05, 2019, 09:32:16 AM »
While waiting for the lastest January data, here is an animation of the full range 1979-2018. Made possible by a recent inclusion of 1979-1999 daily thickness data.

Displayed are thickness data every 5th day to keep the file size relatively limited.

It is coded as an mp4 file, experimental for me, over 13meg in size, see it works for you.

Antarctica / Re: PIG has calved
« on: January 27, 2019, 07:18:04 PM »
SW corner breaking beyond end of small crack - larger ice being propelled by finer debris (as was SE corner last time). Need cloud-free pics to see main crack, more to come this season? Some clockwise circulation near face of glacier, increasing finer debris but area not clearing much.

Edge of fast ice still slowly degrading around Thwaites and its old 'berg.

Antarctica / Re: PIG has calved
« on: January 26, 2019, 05:56:57 PM »
Pine Island Glacier: 18 months of flow and calving

Antarctica / Re: Thwaites Glacier Discussion
« on: January 26, 2019, 01:28:22 PM »
Gif from EOSDIS Worldview (Aqua/Modis)

From 01.01. to today.

Antarctica / Re: PIG has calved
« on: January 21, 2019, 07:43:19 AM »
Degradation as a Gif.

Antarctica / Re: PIG has calved
« on: January 08, 2019, 11:48:23 AM »
Many changes in that area in the past few days.
Here are 3 successive screen shots from Sentinel :
* loss of the iceberg on the east side that were in advance to the main big new iceberg
* on the west side, tremendous outbound movement of the icebergs floating in front of the SW tributary, with additional calving
* movement of the main iceberg towards the exterior

Shean et al., on PIG basal melt: Joughin and Dutrieux among the authors

"Mean 2008–2015 basal melt rates for the full PIG ice shelf were ~82–93 Gt/yr. Local basal melt rates were ~200–250 m/yr near the grounding line, ~10–30 m/yr over the outer main shelf, and ~0–10 m/yr over the North and South shelves, with notable exception of ~50–100 m/yr near the grounding line of a fast-flowing tributary on the South shelf."

Nice pics, i attach two. Scale on the right  is rate of surface height decrease for the first and bed depth on the second.  That huge hole behind the grounding line (white) says that doom is nigh.
open access, read all about it:

Then we have the glaciers next door: Pope,Smith,Kohler aint doin so good either. Sutterly et al. on those, PIG, and Crosson, Dotson ice shelves, open access:

And Getz goin fast: Rippin sounding alarm

" ... the vast majority of the ice shelf (where data is available) is undergoing basal thinning at a mean rate of nearly 13m/a, which is several times greater than recent modelling estimates ... t these measurements represent changes that are significantly greater than modelling outputs, it is also clear that we still do not fully understand how ice shelves respond to warming ocean waters."

open access:


Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 31, 2018, 06:42:59 AM »

December 30th, 2018:
     12,053,135 km2, an increase of 89,101 km2.
     2018 is the 2nd lowest on record.

P.S. I will be on holiday tomorrow and I will post on January 1st, 2019.
¡Happy new year!

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 11, 2018, 02:31:08 PM »
NSIDC Total Area as at 10 December (5 day trailing average) = 9,969,673 km2
Total Area         
 9,969,673    km2      
 65,050    km2   >    2010's average.
 376,092    k   >   2017
-388,039    k   <    2000's average.

Total Gain    92    k   
Peripheral Seas    28    k   gain
Central Seas__    18    k   gain
Other Seas___    46    k   gain
Peripheral Seas         
Bering _______    3    k   gain
Baffin  Bay____    13    k   gain
Greenland____    13    k   gain
Barents ______   -2    k   loss
CAB Seas         
Beaufort_____    4    k   gain
CAA_________   -4    k   loss
East Siberian__    5    k   gain
Central Arctic_   -4    k   loss
Kara_________   -8    k   loss
Laptev_______   -1    k   loss
Chukchi______    26    k   gain
Other Seas         
Okhotsk______   -1    k   loss
St Lawrence___    1    k   gain
Hudson Bay___    46    k   gain
Area gain above average (by 15k) and increasing day by day.
Area now retreating from the approach to the 2000's average, and close to 2010's average.
This is in line with recent very slow gains (and even extent loss) in daily extent (both JAXA and NSIDC data) which is now changing to increasing extent gain.

Other stuff
GFS indicates that overall the Arctic is at a temperature anomaly of around +3.5 to +4 celsius  for the next four days then quickly goes down to about +1. BUT, the strong +ve anomalies on the Atlantic Front persist . In contrast, small -ve anomalies in the Bering and Okhotsk for the next few days.

GFS still saying another pulse of warmer air moving West to East across N. America greatly reducing extreme cold in Central and NE Canada over the next few days or even longer.
Okhotsk, Bering and Chukchi areas are well below zero, and no major pulses of warmth on the horizon. Result is showing in the Chukchi area gains, but not yet elsewhere.

As fierce +ve temp anomaly over the Atlantic front looks like continuing for a good few days more, either losses on the Atlantic front will continue, or gains will be low, until the weather pattern changes. Kara Sea area loss lower on this day at 8 k. Also Central Arctic Sea losses continuing, but also reducing.

Increase in area gain still mainly driven by Hudson Bay (+46k on this day) and Chukchi (+26k). But this is self-limiting as at this rate of gain Hudson Bay Bay will be full-up ice in less than 5 days, and the Chukchi a few days after.

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 11, 2018, 11:15:02 AM »
JAXA ARCTIC EXTENT 11,073,503 km2(December 10, 2018)

- Extent gain at 110 k is  average gain (2008-2017) for this day,
- Extent is 3rd lowest in the satellite record, see Juan's post above for details (and attached table).
- Freezing to date from minimum is 219 k (3.2%) LESS than the 10 year average extent gain,
- On average (last 10 years) 68.6 % of the increase in extent from min to max is done.

An extra line in the table based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average. The outcome from using the 10 year average extent gain from now is a maximum of 14.11 million km2 (230k > 2017).  Using the previous 5 years's average extent gain, the resulting maximum is 13.97 million km2, (80k > 2017).

Extent gain from minimum on this day a little below average. On average (last 10 years)  over 2/3rds of extent gain from min to max is now done with on average 91 days to maximum.

GFS indicates that overall the Arctic is at a temperature anomaly of around +3.5 to +4 celsius  for the next four days then quickly goes down to about +1. BUT, the strong +ve anomalies on the Atlantic Front persist . In contrast, small -ve anomalies in the Bering and Okhotsk for the next few days.
ps: *The 2010's average figure I use in the attached table excludes 2018. I exclude 2018 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 11, 2018, 08:55:06 AM »
2018 had 195 days of Arctic Sea Ice Extent below 11'000'000 km2, which is:

 - 2nd lowest highest on record
 - 6 days more than the 2010's (2010-2018) average
 - 6 days more than 2017
 - 13 days less than the record year 2016

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 11, 2018, 05:22:48 AM »

December 10th, 2018:
     11,073,503 km2, an increase of  110,381 km2.
     2018 is the 3rd lowest on record.

     The 3 lowest years are the last 3 years: 2016, 2017 & 2018.

Arctic sea ice / Re: AMSR2 Sea Ice Volume/Thickness
« on: December 09, 2018, 01:56:15 AM »
I've been brooding over PIOMAS volume data the last 3 days, following some discussion elsewhere about trends vs "weather" and the kind.

I'm staring here as I write at 4 graphs I derived from the PIOMAS data downloaded from the U.of Washington Polar Science center.  I'm pondering what it implies about past changes in the Arctic and what import it has for the future.

Let me back up for a moment and describe what I've done first, and why.

There's been a lot of discussion on the Arctic forums recently around three dimensions we use to evaluate Arctic system health.

In our discussions and arguments we've wrestled with the reality that two of those measures - extent and area, particularly as they appear at the end of melt season - have become increasingly difficult to evaluate to make a skillful determination of how the Arctic will look in a few years. Our discussion has shifted and expanded now to where over the last two years there has been much more tracking and examination of the annual refreeze.  This has given us some hints and generated quite a few more questions.

Roll back to what I'm doing now.  I'm using PIOMAS daily volume data going back to 1979 (

My analysis is more empirical than theoretical.  At this moment I'm less interested in prediction than I am the data set.  I have a particular interest in volume as well. Unlike extent and area, it represents a far better proxy for key forces at work in the Arctic - heat exchange and total system enthalpy.

My second purpose is contrast volume changes with changes that have taken place during the time period in question and see if a pattern appears which follows or is affected by them.


Simply digesting a raw and fairly substantial pile of data is unlikely to produce anything useful.  However, I don't want to fall into the trap of over-analyzing the information - while it is good to reduce "noise", over-processing values can remove meaningful signals it contains.  My approach to this is three fold.

1) Create a sample average from a meaningful but more controllable time frame.

Most analysis of this data has been around extreme endpoints in annual variation - the annual maximum extent/area/volume and corresponding minimum - which land on arbitrary dates and are very narrow samples.  For my work here, I've picked to arbitrary but significant dates March 21 (Day 80/81 of each year) and September 21 (Day 260/262).  I then averaged the daily volume for a time frame window which extends from two weeks before until two weeks after those dates to get what I call "Vernal" and "Autumnal" volume numbers for those dates.

My logic in doing this is this: Rather than use a metric which is volatile and fundamentally disconnected from other forces in play at the time they take place (annual minimum/maximum), I wanted to anchor the analysis to two specific points in them where we know predictable and measurable changes are taking place (the Spring and Fall equinoxes).  Further, to make the new metric sensitive to conditions during the specific year and season, rather than simply pluck out one number, an average over a near-term time frame would better incorporate and smooth other signals from forces in play at the time.

In addition to these two numbers, I also created a baseline value for tracking behavior on a broader time scale.  In this case, I created an annual average for each year, summarizing all volume measurements from January 1 to December 31 for each year in question.

2) Create a derivative average which further smooths the Vernal and Autumnal numbers over a wider time frame. 

In this case, I created a second data set from my spring and fall averages, starting with 1983, which is a simple 5 year running average of those numbers.  The goal here is to round off peaks and valleys without losing all of the signal they contain, and hopefully permit underlying trends to be more visible, and more importantly, better identify transitions in system behavior.

3) Create a third derivative/index to show system volatility.

At the start, these were actually the numbers I was most interested in. We've discussed this some on the forums, but the summary of my thought here is, this, and also may qualify as a hypothesis:  As the Arctic as a system approaches behavioral limits, the volatility of the system - the relative change against base values - will increase.

Again keeping it simple, I created three values for each year in question.  These were (a) The absolute difference between Vernal and Autumnal values (b) the Percent that value represented of the Vernal volume and (c) the Percent that value represented of the Annual volume as derived in (1) above.  I did this for both the raw and 5 year running averages of Vernal, Autumnal and Annual values.

Note: all values I used were rounded up to three decimals. I figured the significance of fractional cubic KM of ice were meaningless based on the confidence of the measurements.


From raw data and graphic analysis by Jim Pettit, Zach Labe and many others it's already clear that sea ice volume has been declining steadily over the time period in question.  What isn't necessarily clear is the nuances of how those changes have taken place.

Both the smooth and averaged data clearly shows this trend. No surprises (nor were any expected).

However, annual seasonal loss has shown only a very modest increase - less than 10% over all - with an average of 14.242K KM3, median of 14.034K KM3 and deviation of 1.164K KM3.  Breaking the loss dataset in half shows the 2nd half loss rate only increasing by about 1000KM3, and 2nd half loss volatility actually declined slightly. The 5 year running averages are correspondingly closer.  This suggests strongly that large year to year variations in melt are not significant contributors to the reduction in volume over the period measured.

The first think that jumped out at me in particular in the averaged data, is I think I'm seeing two historical locations where I think there's a signal identifying a fundamental change in how the system behaves.  The first is in the 1990-1994 time frame. There I think spring, fall and yearly average graphs start a break in slope, falling into the glide path that takes us down hill to where we are now.  I'm not sure what the specific conditions were at the time, or, considering hysteresis, how far back we need to look for the trigger, but it strikes me that is a specific place in time and space we can point at where the system signals a change has taken place.

The second was the 2010-2013 time frame.  in that range all three measures - Annual average, spring and fall - flatten out.  As another interesting and possibly key item, annual loss intersects and then starts to follow the annual average curve.  I'm not sure what this means yet, but it sure looks like a strong signal.  Also, while the three major curves flatten, the *vernal* curve is still trending down.  I think the running 5 year equinox graph shows this the best.

My general take away - I think the graphs support another of my thoughts - that as the total energy available to the system increases (reduced ice), the overall volatility of its metrics will increase - especially area and extent - which actually are more derivative of this than volume.

I'll be interested to hear what other folks think.  If someone can point me in the right direction, I'll post the spreadsheet with my raw numbers someplace for people to tear apart.

 (P.S. - the average volume will be off a bit for 2018 as we haven't finished the year.  That said, we are far enough along it that the relative change is small enough to be negligible to my analysis.)

Arctic sea ice / Re: Latest PIOMAS update (November)
« on: December 04, 2018, 05:44:14 PM »
Same comment than last month:

Focusing on what has happened…

I started contact with Neven in May or June 2012 and I was shocked with the ASI drop on August, after the Great Arctic Cyclone. I was also impressed by the 2012 PIOMAS Volume graph made by Wipneus. So, when on the first months of 2013 appeared cracks on the ASI, well, several of us were concern of what could happen that year. Finally, 2013 was a good year for the ice and 2014 was even better. It had passed 6 years since 2012 and the collapse has not happened.

Or it has happened?  :o

On extent, the ASI has not even able to break the 2007 record, not to mention the 2012 record. So, there are some people saying that 2012 is an outlier and even 2007 will be difficult to break. But I don’t like extent! Yes, it is important to measure the effect of the Arctic Ocean albedo. But to measure the ASI drop, I am convinced that we should use volume, even if it is harder to measure than extent.

So, what do I see on volume?

First, [September] volume on 2007 has been broken several times. On volume, 2007 is the ninth lowest on record! And even that September 2012 is still the lowest, the difference between 2012 with 2010-2011 and 2016-17 is not that big.

But on the other hand, while 2012 has not been broken, the decadal average show us that we
have a very different Arctic. By example, look at Aug-Oct average on a decadal basis.  The 1990-99 average of 93.6% changed to 68.5% on 2000-09 and to 39.5% on 2010-18.

So, do we need a catastrophe to prove a catastrophe? From my point of view, the catastrophe has already happened. The [Aug-Oct] 39.5% ice that we have on 2010-18, versus the 1979-2000 baseline, is climate change, not just one year, not weather change.

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 02, 2018, 03:41:54 PM »
November has passed, so time for a full set of NSIDC Area Graphs (plus a look at what might happen during December)

St Lawrence - not in play until January.

Here is a table of complete guesses on the area gain until Dec 31. Believe the table and you will believe anything (even the President of the USA).

Sea    Area gain in Dec? (k km2)
bering   250
chukchi   300
okhotsk   175
baffin   200
greenland   100
barents   100
kara           100
laptev                    0
beaufort                    0
east siberian            0
canadian archipelago   20
central arctic         100
hudson bay         600
st lawrence           15
Total                       1,960

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 02, 2018, 03:32:07 PM »
November has passed, so time for a full set of NSIDC Area Graphs (plus a look at what might happen during December)

Central Arctic Seas

Beaufort Sea -
Canadian Archipelago-
East Siberian Sea -
All nearly completely frozen and earlier than 2010's average date

Central Arctic - dithering at 2010's average. perhaps another 100,000 km2 area gain to go, but could take three months.

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 02, 2018, 03:23:45 PM »
November has passed, so time for a full set of NSIDC Area Graphs (plus a look at what might happen during December)


Baffin Bay - Strong gain to mid-November followed by average gain. Area currently at 2000's average.

Hudson Bay - a week's blip in gain has delayed the refreeze by a week, but should be complete by end-December at 2000's timetable. BUT highly sensitive to air temperature anomalies in the region.

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 02, 2018, 03:16:56 PM »
November has passed, so time for a full set of NSIDC Area Graphs (plus a look at what might happen during December)

The Atlantic Front.

Greenland Sea - Very much affected by amount of ice coming down the Fram Strait. But excluding that seems to show the sea is losing ice and may stay in record territory.

Barents Sea - Below 2010's average area and at or below average area gain at the moment.

Kara Sea. What a surprise. Re-freeze almost complete five weeks early. So further area gain will be minimal.

Laptev Sea  re-freeze complete

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 02, 2018, 02:40:57 PM »
November has passed, so time for a full set of NSIDC Area Graphs (plus a look at what might happen during December)

The Pacific.
The Okhotsk - if freezes early, apparently it helps to guide storms towards the Bering Strait, promoting slow freeze and early melt. A bit below average area gain at the moment.

Bering Sea - very much below average area gain at the moment.

Chukchi - much depends on SSTs, any thick (and other) ice pushed into it from the Beaufort, and if southerly winds come in from the Bering. Well below 2010's average area and at average area gain at the moment.

Arctic sea ice / Re: Latest PIOMAS update (November)
« on: November 07, 2018, 03:42:43 AM »
PIOMAS Volume - Arctic sea ice change versus 1979-2000  :)

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: October 10, 2018, 12:21:33 PM »
Just an idea for Juan C.Garcia's table. I like it very much, and would find interesting, specially this year, to have one extra column showing the difference between curent value and yearly minimum.  This would allow to see what is the freezing trend.

Like this?  ;)

Arctic sea ice / Re: Latest PIOMAS update (August)
« on: August 08, 2018, 11:27:59 PM »
the major change in ASI happened in 2007. Since then only minor changes have occurred, expressed mainly in further reduction of volume, especially in OND due to later freezing / intrusion of warmth through the Atlantic side.
Yes, 2007 in some ways had a more dramatic downstream impact than 2012, pinching out MYI classes as well as subsequent volume by the mechanism discussed below. The NSIDC account of Sept-Oct 2007 is at the link below; the overlay of the 2007 minimum on 07 Aug 18 AMSR2 is shown in the attached png.

It looks like most of the 'extra ice' this year will be midway between the NP and Wrangel/NSI. GFS surface winds suggest the peculiar lift-off in the Lincoln Sea will continue a few more days; however a few days of opposing winds later in the month could flatten it against the coast, making the final outline of 2018 ice look even more like 2007.

Delayed freeze-up in the fall prolongs the local melt season in warm-water kill zones and otherwise offer a chance for consolidating winds. This in turn restricts the seed pack to the CAB (recalling that new ice mainly forms on the pack periphery), resulting in an ever higher proportion of FYI relative to SYI.

The second animation shows that ice loss between early August and mid-September is quite variable, with GAC2012 bringing about the most extreme situation in just a few days. Looking at this time series makes me dis-believe the hastily written journal articles post-GAC saying 'oh that ice would have melted out anyway'.

This animation advances in triple frames: first the August 5th for the earliest year, then its September 10th, then the half-overlay of the minimum on the August, pause, then the next triple, up to the 2018 whose minimum and overlay frames are conjectural.

It's also worthwhile to compare each melt season end to its beginning (notably Sept 2017 to Sept 2018) if you take the view that the CAB largely just sits there from year to year (possibly thinning slightly) and melt season primarily consists of undoing undoing the freeze season's new peripheral ice. In that perspective, the year is evaluated by its departure from time-reversibility: did the melt season do less or more than undo its freeze season.

However this year has seen significant inroads into the CAB along the Atlantification corridor, in the Laptev and possibly the Lincoln Sea (where Atlantic Waters eventually exit out the Nares at depth).

While lift-offs are as common and in correspondence with sustained CW rotation of the ice pack (ie anti-cyclonic pressure systems), this one could be unveiling a severely mechanically weakened -- and possibly thinned -- local ice pack.

Recall though the winter Ascat series that showed almost half the very thickest east Lincoln ice getting pushed down the Nares, so quite a bit there is just refrozen matrix, now breaking up into free floes.

Recall too that the interface of the CAB with the outer islands of the CAA was in motion for much of the fall and winter, with huge blocks tumbling end over end and some exiting into a Beaufort-Chukchi stringer. Even though this area might see some of the coldest mean temperatures and historically have been land-fast, in recent years with a smaller rotating rigid body, it is moving fast on the outside of the merry-go-round and coming up against these immovable islands. Much of the very thickest and oldest MYI has been lost in this way.

Arctic sea ice / Re: Latest PIOMAS update (August)
« on: August 06, 2018, 09:40:30 PM »
Using the decades averages on the graph seems to make it clear volume loss is accelerating.

I like to do my PIOMAS analysis on a decadal basis.

From my point of view, it is not important anymore how we end up on 2018 or 2019.
The important thing is to talk about climate, and a decadal change is a measure of climate (not a particular year).

So, the important point is that looking at September, we lost 32.7% of the volume on 2000-09, but we lost almost the double (63.6%) on 2010-2017.

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: August 03, 2018, 09:29:00 PM »
I am not sure there is a lot of logic with how the sea boundaries are defined but if we want to be able to compare years and trends, we need to use a standard, consistent definition.

However you draw the boundaries of seas, the method is arbitrary. If we really want to discuss what is going on in the Arctic using a truly scientific perspective, it would make far more sense to evaluate ice based on bathymetry, the location of islands and currents etc.

For the data I post, I have to use what I am given on a consistent basis. So I use for area analyses the NSIDC definition of the various seas as shown in MASIE ( ) which also gives instant access to maps of extent by those seas.

I don't think that anyone (but Wipneus !) is going to go back and realign the data from 1979 to date according to boundaries defined by "bathymetry, the location of islands and currents etc ", especially as some parameters, e.g.s currents, limits of seas (especially peripheral seas), have and will change as sea ice declines.

BUT, on the melting season thread, images and comments are on areas that ignore boundaries, as sea ice changes (extent, thickness et al) and weather ignore the lines cartographers put on the maps. And a good thing too.

As far as basic extent and area data is concerned, my major concern is the lack of news on any plans to ensure the data record is maintained after the last USAF satellite and the Japanese satellite croak, expire, are no longer extant.

Without data we are stuffed.

Arctic sea ice / Re: The 2018 melting season
« on: August 03, 2018, 07:56:41 PM »
Bbr .. they are short of cherry pickers in England atm ... :)

if we permanently take the longest possible forecast that almost never becomes true it not only looks bad but causes irritations and useless discussions. if i were @neven i'd not allow more than 5days forecast images to be posted, even that's not worth the effort because too much is changing in the meantime while at least we often get close.

if we want to know how the weather will NOT be in 10+ days we simply have to look at the forecast weather and sadly that's not even kidding.

in short i agree while cherry picking is a nice word for a PN. i'd gladly not use abbreviations but forthe sake of peace, those who think similarly can guess the two words behind LOL

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: August 03, 2018, 03:13:31 PM »
The relative cliff continues... JAXA extent lost 1.863 M km2 in 17 days, quite extreme for the period.

I'll take this opportunity to thank again Juan C. Garcia and gerontocrat for your updates on this most important matter. I am sure I am not the only addict.
You are welcome everybody!

The true is that this Forum is a team work and it is impossible to make a explicit thanks to everyone. But I am sure that a lot of us enjoy the multiple posts that are making us able to follow the Cryosphere and the Antrophogenic impact that we are doing on our planet.

So Thanks everyone for the work that you are doing on this Forum!  :)
Thanks to the external groups also, like ADS-NIPR (JAXA), PIOMAS, NSIDC, OMG, etc.

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