JAXA still not showing the graphs and the data for 2018, so I had a look at the NSIDC daily data spreadsheet.
NSIDC extent dropped quite a bit, pretty much removing yesterday's upward spike.
2017 extent barely grew over the second week of January, but shot upwards nearly a million km2 in the second half of the month. IOW, we can expect 2018 to fall into second place over the next day or two, and remain there until at least the 18th or so.
Both GEFS and EPS ensembles are mostly in agreement on a synoptic setup that supports warm anomalies driven from subtropical advection on both the Atlantic and Pacific sides in the 5 day to 2 week mid range.
On the Pacific, a return of strong -EPO conditions starting around 5 days out will support another round of anomalies on the Pacific side. In the Atlantic, a strong pressure gradient along the NAO will transport subtropical moisture over the Greenland and Barents seas.
JAXA 2018 data and extent graphs still not available., so I sent a polite e-mail to the Japanese National Institute of Polar Research to ask when it may appear.
Will they answer?
JAXA 2018 data and extent graphs still not availableDitto NOAA's RASM-ESRL: it is still frozen on 26 Dec 17 with no advisory 13 days later about when or if it will resume. [[Update: forecasts to resume 14 Feb 18]]
Japan does well for National Holidays. Perhaps tomorrow may see some scientists and technicians stagger into work.JAXA 2018 data and extent graphs still not available., so I sent a polite e-mail to the Japanese National Institute of Polar Research to ask when it may appear.
Will they answer?
Not sure. But I follow their Twitter feed, and they're normally pretty good about keeping up-to-date in regard to outages. But there's been no such tweet lately, so I assume they're just on break, maybe?
NSIDC extent down yet again:
Of course, record low winter extent doesn't mean record low summer extent (see: 2017).
I had received an e-mail stating that something had been changed in the JAXA SIE data sheet, but now the ADS NIPR site can't be reached. Has anyone seen whether data had been updated? I know it's winter/hibernation time, but 10 days of no data is too much! ;)I am encouraged that the site is now down - perhaps that means they are trying to fix the problem.
10 days of no data is too much!RASM_ESRL to resume its forecasts on 14 Feb 18. After a 50 day hiatus! No word on whether they will infill missing data days nor if algorithm is changing (and backwards-comparable). Possibly a good window to get in comments, feature requests and bug reports. Email contacts on web page.
Life must be very difficult at NOAA at the moment - they still do not know how much they will be clobbered when the 2018 Federal Budget is decided. I understand that at the moment they are on 2017 pro-rata budget levels. Something might be decided at overall level in the next 10 days.Quote10 days of no data is too much!RASM_ESRL to resume its forecasts on 14 Feb 18. After a 50 day hiatus! No word on whether they will infill missing data days nor if algorithm is changing (and backwards-comparable). Possibly a good window to get in comments, feature requests and bug reports. Email contacts on web page.
https://www.esrl.noaa.gov/psd/forecasts/seaice/
Hey-ho, we may still book passenger flights crossing arctic to get data :P . Remember tuesday updates on windows-machines may be a bit more tricky this time around. For sure, some of JAXA stuff runs on Linux, but will the updates talk to each other?
Hey-ho, we may still book passenger flights crossing arctic to get data :P . Remember tuesday updates on windows-machines may be a bit more tricky this time around. For sure, some of JAXA stuff runs on Linux, but will the updates talk to each other?
Recently flew Tokyo to London and noticed that the plane did not cross into the Arctic despite it being the shortest route. so don’t go booking Arctic flights without checking if the plane goes there. is avoiding the Arctic normal practice for commercial jets?
Jim Petit wrote back in #637 of 2017: I spend a few daysof the new year tweaking all my graphs and charts. I've read the suggestions for changing the baselines and so on; any changes incorporating those suggestions will be made public in early January.@zlabe linked to the definitive meteorological article used to justify climate baseline definitions, anomaly charts, and what to do during periods of rapidly changing baselines, first article below. It has been cited 131 times; I chased through those to find the best five, all free full text.
JAXA DATA AS AT 12 JAN 2018. Hoorah..
Extent gain on average is 86% done, there is on average 62 days to go to maximum. Extent is still just lowest in the satellite record, and as commented above, is likely to be second on the 13th for a couple of days, and then possibly to be lowest again.
Historical data still strongly suggests a low or record low maximum. We will see.
<snippage>I find myself increasingly leaning towards using running 5 year averages for net losses/gains when making these comparisons. My hunch is they will better reflect the more recent trend.
I note that based on previous year's actual increases from this date (actually, yesterday), a new record low ASI maximum will likely be attained (but not by following 2012's increase). Also, not only 2012-styled sea ice net loss but also 2016 mimicking net loss will cause a record or near-record September minimum.
I note that based on previous year's actual increases from this date (actually, yesterday), a new record low ASI maximum will likely be attained (but not by following 2012's increase). Also, not only 2012-styled sea ice net loss but also 2016 mimicking net loss will cause a record or near-record September minimum.We will quite likely get a near-record or a record, but I'd like to point out that a major reason for the record low extent in the fall and early winter comes from delayed refreeze, rather than avoided refreeze. This can easily be seen in the Chukchi where the ice-free season is longer by about 2 months compared to even a few years ago, but extent still reaches the maximum possible in the dead of winter. Some peripheral seas do have areas that may avoid refreeze (especially Bering and Barents, also Baffin and the mostly irrelevant but volatile Okhotsk), and that is where the record is decided.
I find it curious that the Pettit JAXA Arctic Extent projection available on the ASI Graphs (https://sites.google.com/site/arcticseaicegraphs/) page (reproduced below) is not obviously available on Jim Pettit's linked website (https://sites.google.com/view/pettitclimategraphs).
<snippage>I find myself increasingly leaning towards using running 5 year averages for net losses/gains when making these comparisons. My hunch is they will better reflect the more recent trend.
I note that based on previous year's actual increases from this date (actually, yesterday), a new record low ASI maximum will likely be attained (but not by following 2012's increase). Also, not only 2012-styled sea ice net loss but also 2016 mimicking net loss will cause a record or near-record September minimum.
In this case, the longer trend incorporates larger increases and losses than have been typical the last few years, and I think weigh the averages in ways that aren't really reflective of the changing conditions.
I'm for me to dust off my spreadsheets, download some SIE/SIA data and crunch numbers again.
What I am finding interesting in the estimate of the increase to maximum is the way that the linear trend line over the past fortnight has moved from showing almost no change since 2003 to showing a significant decline of about 250,000 km^2 currently. Each of the past three years have been impacted by the El Nino, producing warmer Pacific water and have very low increases from yesterday to the max. Meanwhile 2012 may have been impacted by the 2010-12 La Nina, and cooler water, causing greater than normal increases. Pacific waters are again warmer this year and I am not expecting a lot of sea ice to form in that area.<snippage>I find myself increasingly leaning towards using running 5 year averages for net losses/gains when making these comparisons. My hunch is they will better reflect the more recent trend.
I note that based on previous year's actual increases from this date (actually, yesterday), a new record low ASI maximum will likely be attained (but not by following 2012's increase). Also, not only 2012-styled sea ice net loss but also 2016 mimicking net loss will cause a record or near-record September minimum.
In this case, the longer trend incorporates larger increases and losses than have been typical the last few years, and I think weigh the averages in ways that aren't really reflective of the changing conditions.
I'm for me to dust off my spreadsheets, download some SIE/SIA data and crunch numbers again.
For an early version of this graph I actually used discrete five-year averages at first, then five-year moving averages. In my mind, they were both a little messy and not as helpful as I was aiming for, so I chose instead to color-code the annual lines by decade. In case you're wondering. ;-)
What I find to be interesting is that much of the sea ice extent is seasonal ice, so much of the gain's that we've seen this year will disappear shortly into the warming season.You'll find a graph here that shows you that.
i'd be more interested in knowing the thickness of the perennial sea ice that remains at the end of the summer.
I'm for me to dust off my spreadsheets, download some SIE/SIA data and crunch numbers again.
Are those graphs updated automatically if I just refresh that website every month or so?Many of the graphs are linked to the source data and most are updated regularly. They are definitely a good source of information.
I wish the L. Hamilton contributions on the Long-term Graphs (https://sites.google.com/site/arcticseaicegraphs/longterm) page would get updated.
Is there any possibility of a flatline for a month?It would have to be the first time it happened at this time of year (might happen very close to before and after maximum?)
JAXA DATA as at 26 Jan
About 4 weeks and 9% of extent gain to go. Extent today down by 1k km2.Each update points a bit more firmly to a record low maximum. Even if there is a largish extent gain from now, that ice will be very thin.
JAXA DATA as at 26 Jan
About 4 weeks and 9% of extent gain to go. Extent today down by 1k km2.Each update points a bit more firmly to a record low maximum. Even if there is a largish extent gain from now, that ice will be very thin.
What is the date, on average, that maximum extent is reached? Is the extent maximum or melt onset occurring earlier in the year?
JAXA DATA as at 26 Jan
About 4 weeks and 9% of extent gain to go. Extent today down by 1k km2.Each update points a bit more firmly to a record low maximum. Even if there is a largish extent gain from now, that ice will be very thin.
What is the date, on average, that maximum extent is reached? Is the extent maximum or melt onset occurring earlier in the year?
No definite trend on this what I remember, the reason why I asked about the flatline month is that I've got no idea what North Pacific and North Atlantic are doing just now.
JAXA DATA as at 26 Jan
About 4 weeks and 9% of extent gain to go. Extent today down by 1k km2.Each update points a bit more firmly to a record low maximum. Even if there is a largish extent gain from now, that ice will be very thin.
What is the date, on average, that maximum extent is reached? Is the extent maximum or melt onset occurring earlier in the year?
No definite trend on this what I remember, the reason why I asked about the flatline month is that I've got no idea what North Pacific and North Atlantic are doing just now.
The Arctic melt season is lengthening. Is that because freeze onset is occurring later in the Fall?
Is there any possibility of a flatline for a month?
The Arctic melt season measured by time elapsed from date of maximum to date of minimum is NOT lengthening. What is happening is that there are places that used to have sea ice that now usually never have it, i.e. no freezing season and no melt season. Other places are now ice-free for a longer time (e.g. Hudson's Bay). (One day per year average?)
JAXA DATA as at 26 Jan
About 4 weeks and 9% of extent gain to go. Extent today down by 1k km2.Each update points a bit more firmly to a record low maximum. Even if there is a largish extent gain from now, that ice will be very thin.
This season we started off cooler, but may be finishing warmer than last year.
I suspect we'd be better off if it were the other way around.
The Arctic melt season measured by time elapsed from date of maximum to date of minimum is NOT lengthening. What is happening is that there are places that used to have sea ice that now usually never have it, i.e. no freezing season and no melt season. Other places are now ice-free for a longer time (e.g. Hudson's Bay). (One day per year average?)I think the best measure is something that shows the lengthening of the ice-free period. Using Wipneus' AMSR2 regional extent chart, I made this crude animation showing my thinking. Define "Less than full ice cover" as <95% coverage, and "Nearly ice-free" as <10% coverage. Of course, these are arbitrary thresholds.
So in Hudson's bay you would see a shorter melt season if you measured time elapsed from date of maximum (100% ice) to date of minimum(zero-ice), and a longer melt season if you measured time from date of maximum sea ice to date of ice starting to reform.
The confusion is looking at the Arctic as a whole versus places on the periphery. It is quite confusing.
The fact remains that at 26 Jan 2018 there is 2.1 million km2 less Arctic sea ice than the 1980's average.
Not quite the bottom dropping out, but a nonetheless remarkable late-January departure:
Click for current full-size image:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fiwantsomeproof.com%2Fextimg%2Fsie_nsidc_six_week_detail.png&hash=daed5fdc1da70674f1a8b83169859375) (http://iwantsomeproof.com/extimg/sie_nsidc_six_week_detail.png)
It's a little sobering to consider that the lows we're witnessing today with a mixture of odd excitement and plain terror will all be beaten within 10 to 12 years.
2018 set record lows in the NIPR Extent record almost every day in January, nearly wiping 2006 off the chart in the process. It's a little sobering to consider that the lows we're witnessing today with a mixture of odd excitement and plain terror will all be beaten within 10 to 12 years.A. Thanks for the interesting table, and you're probably right with your reasoning. However,
JAXA DATA - Extent as 2 Feb is 13,251,377 km2The coming cyclone may briefly *increase* extent while potentially reducing area. It will stir things up no doubt. Key question for me is whether the heat drug up from depth results in an early max.
Extent gain continuing to accelerate, up another 96 k. Average extent gain in the these last 6 weeks remaining of 0.72 million would produce a maximum of just under 14 million km2, whoopslessgreater than than last year's record low of 13.88 million km2..
Perhaps the extraordinary cyclone due to start roaring up into the Greenland Sea to over the North Pole will change things for a few days?
It's not just one cyclone. It's a vortex around Greenland that will bring repeated intense storms with huge waves. Watch for Jim Hunt to drop into Nazarre with his longboard. Seriously, the wave trains in the north Atlantic and the sub Arctic seas are going to be massive. Expect massive destruction of sea ice on the Atlantic side of the Arctic and sub-Arctic.I see that looking at nullschool. Persistent 6-10M waves with 10-15 second periodicity, over a period of 72+ hours. That will stir up the top 2-300 meters of the water column quite thoroughly.
Watch for Jim Hunt to drop into Nazarre with his longboard
Those maps shows 10 meter high, 15 second period waves heading straight for the ice edge north of Svalbard.
It would be interesting to review the predictions from a week ago to see if the big increase in extent during the last week was indicated. Most of this increase occurred between Baffin and Barents. If the current predictions are correct I would expect to see the extent increases of the last week largely reversed.It's not just one cyclone. It's a vortex around Greenland that will bring repeated intense storms with huge waves. Watch for Jim Hunt to drop into Nazarre with his longboard. Seriously, the wave trains in the north Atlantic and the sub Arctic seas are going to be massive. Expect massive destruction of sea ice on the Atlantic side of the Arctic and sub-Arctic.I see that looking at nullschool. Persistent 6-10M waves with 10-15 second periodicity, over a period of 72+ hours. That will stir up the top 2-300 meters of the water column quite thoroughly.
You are right. I think the Barentsz in particular is going to get clobbered, especially as there is already a lot of imported "warm" Atlantic water there at depth.
<snippage>A possible max on Jan 31 or thereabouts?
It would be interesting to review the predictions from a week ago to see if the big increase in extent during the last week was indicated. Most of this increase occurred between Baffin and Barents. If the current predictions are correct I would expect to see the extent increases of the last week largely reversed.
Ouch. He faded right into taking that bomb on his head.
I hope the orthopods were able to put him back together.
I hope the orthopods were able to put him back together.
For the second day in a row, NSIDC reports a century break, down 114K(!) How many times have there been a century break in February and how many times have there been two consecutive days with a century break?NSIDC says 2018 is 134k < 2017, JAXA says 2018 is 100k < 2017. So 2018 is in charge, at the moment....
Meanwhile, Antarctica lost 58K so the global sea ice extent loss were a decent -172K. Is that lowest on record or is 2017 still in charge?
For the second day in a row, NSIDC reports a century break, down 114K(!) How many times have there been a century break in February and how many times have there been two consecutive days with a century break?
For the second day in a row, NSIDC reports a century break, down 114K(!) How many times have there been a century break in February and how many times have there been two consecutive days with a century break?
There have only been five century+ decrease in NSIDC ASI extent over the past ten Februarys, and only ten total for the month since 2000; two of those have occurred over the past two days, so it's definitely a rare thing. There have been no back-to-back century+ decreases since 2000; in fact, only 2007 saw more than one for the entire month.
based on statistics over the past ten years (2008-2017):
--IJIS extent is projected to reach of a maximum of 13.67M km2 on March 16, an additional increase of 424k over the next 36 days, or 11.78k per day.
I'm not sure what you are saying. You are talking about the maximum, but in your calculation you only used the extent values for 16 March? How about years with an earlier or later maximum? The JAXA extent on 16 March is on average about 0.1 million km2 lower than the maximum.
I wrote that my projections were "based on statistics over the past ten years (2008-2017)". That is, if SIE were to increase at the mean average rate measured over the past ten years, we'd see the maximums I mentioned. Also, if SIE were to behave in line with the mean average of those same ten years, this year's maximum would occur on those dates I mentioned. These visualizations might help:
Click for most recent full-size image:
(https://i.imgur.com/DTNIASq.png) (http://iwantsomeproof.com/extimg/sie_projections_from_current_date.png)
That method is biased low for estimating the maximum. By taking the average trajectory over the past 10 years, you get an unrealistically smooth trajectory, which remains basically flat during mid-March. In reality, the trajectories for individual years fluctuate much more. You only need a brief upward fluctuation to increase the maximum for a given year.
That method is biased low for estimating the maximum. By taking the average trajectory over the past 10 years, you get an unrealistically smooth trajectory, which remains basically flat during mid-March. In reality, the trajectories for individual years fluctuate much more. You only need a brief upward fluctuation to increase the maximum for a given year.
To get a corrected estimate for the 2018 JAXA extent maximum using that method, you would have to add about 0.1 million km2 to your calculated numbers. For the NSIDC one-day extent maximum, the correction would be about 0.15 million km2.
That method is biased low for estimating the maximum. By taking the average trajectory over the past 10 years, you get an unrealistically smooth trajectory, which remains basically flat during mid-March. In reality, the trajectories for individual years fluctuate much more. You only need a brief upward fluctuation to increase the maximum for a given year.Good point. The chance of hitting a given maximum goes up with higher volatility, even when the average trajectory remains the same.
In 2018 extent has been less than 2017 36 days out of 43.
Gerontocrat, thank you for your daily updates and analysis on this and other threads.Unprecedented it is - I just add here Feb 14 vs Feb 6.
I want to add this chart from Wipneus' regional AMSR2 extent page, which explains a whole lot about the 2018 record low, and provides a lot to worry about for the coming melting season. Unprecedented is too easy a word for this.
Cor blimey. Stunning graph. Game changer ? Time to think aout what happens in the spring and summer?
I want to add this chart from Wipneus' regional AMSR2 extent page, which explains a whole lot about the 2018 record low, and provides a lot to worry about for the coming melting season. Unprecedented is too easy a word for this.
GFS and EURO are both in agreement over a major heatwave and/or LP event for Greenland + Arctic D8-10.
Sea level rise is a very slow process. Arctic temp anomalies for this freeze season have no impact.
Impact yes, large no. The loss of floating ice has no impact on sea level promptly. It has secondary impacts that feed back loops that will contribute.Sea level rise is a very slow process. Arctic temp anomalies for this freeze season have no impact.
I'm sorry, but you're just 100% wrong. No impact? Where do people like you get your information?
What really concerns me is how late the freeze occurred on the Pacific side. The Beaufort, Chukchi, Bering and ESS all struggled to freeze over. This meant these seas had far less time to thicken and, given the ridiculous warm anomalies on the Pacific side this winter, we have dangerously thin ice heading into this melt season.Agree - it's not extent or area, its volume I'm worried about.
What really concerns me is how late the freeze occurred on the Pacific side. The Beaufort, Chukchi, Bering and ESS all struggled to freeze over. This meant these seas had far less time to thicken and, given the ridiculous warm anomalies on the Pacific side this winter, we have dangerously thin ice heading into this melt season.Agree - it's not extent or area, its volume I'm worried about.
Extent is a secondary problem, and for all of our new min-maxes happening, the effect of that difference is trivial compared to the last 3 years. The heat provided by open water will not be significantly greater.
Impact yes, large no. The loss of floating ice has no impact on sea level promptly. It has secondary impacts that feed back loops that will contribute.Depends on the size of the floating ice, and where it floats to. If it's an Antarctic floater, a really big one, it can melt fast if it floats Northwards, and it will give a measurable SLR result worldwide.
Yes, essentially correct.<snip>
Agree - it's not extent or area, its volume I'm worried about.
Extent is a secondary problem, and for all of our new min-maxes happening, the effect of that difference is trivial compared to the last 3 years. The heat provided by open water will not be significantly greater.
I was given to understand that the negative feedback was all about additions to ocean heat during the insolation season, year after year after year. After all, there are about 2 million km2 of open water today on the fringes of the Arctic where in 1979 there was ice. If a simple average is used, say about 1 million sq kms that has been absorbing most radiation instead of reflecting most radiation for nearly 40 years.
Perhaps extent may not matter so much for an individual melting season, but surely it matters for long-term heating of the biosphere?
How do you get that?Impact yes, large no. The loss of floating ice has no impact on sea level promptly. It has secondary impacts that feed back loops that will contribute.Depends on the size of the floating ice, and where it floats to. If it's an Antarctic floater, a really big one, it can melt fast if it floats Northwards, and it will give a measurable SLR result worldwide.
.... + 6.7 C in the arctic!!????It's best not to extrapolate from.extreme events to a whole year. Also if you take a look at the DMI "North of 80o" chart, spring/summer anomalies in recent years are much closer to zero, from around day 120 to day 220, regardless of winter anomalies.
1. How is it even possible to have ice in the arctic at the end of this coming melt season with anomalies like that during the refreeze period?
2. What happens if these temperature anomalies keep up for the rest of the year?
3. How much sea level rise are we going to see if we get 7C anomalies for the rest of the year?
I also recommend using better decorum in forum posts.Sea level rise is a very slow process. Arctic temp anomalies for this freeze season have no impact.I'm sorry, but you're just 100% wrong. No impact? Where do people like you get your information?
What really concerns me is how late the freeze occurred on the Pacific side. The Beaufort, Chukchi, Bering and ESS all struggled to freeze over. This meant these seas had far less time to thicken and, given the ridiculous warm anomalies on the Pacific side this winter, we have dangerously thin ice heading into this melt season.Agree - it's not extent or area, its volume I'm worried about.
Extent is a secondary problem, and for all of our new min-maxes happening, the effect of that difference is trivial compared to the last 3 years. The heat provided by open water will not be significantly greater.
I was given to understand that the negative feedback was all about additions to ocean heat during the insolation season, year after year after year. After all, there are about 2 million km2 of open water today on the fringes of the Arctic where in 1979 there was ice. If a simple average is used, say about 1 million sq kms that has been absorbing most radiation instead of reflecting most radiation for nearly 40 years.
Perhaps extent may not matter so much for an individual melting season, but surely it matters for long-term heating of the biosphere?
Again, please move non ice related discussion to a Consequences thread.
Harpy, I will respectfully disagree.
If you look at the behavior of ice extent growth in the latter part of the freeze season over the past 5 years, there is a pronounced, step wise trend downward. Likely the result of our rapidly warming Arctic winters?
“So it goes - yet another anomalous winter in the #Arctic. Total sea ice extent remains at a record low (satellite era) and nearly 1.5 million km^2 below average [@NSIDC data] ”
https://twitter.com/ZLabe/status/965606352969072640
Image below.
A 2018 edition of the graph I put out a few times last year. The black dots are the maxima for previous years (timing and extent); the grey area is the extent range for each day. I'll update from time to time to the end of March.
(PS I've changed my pseudonym from deeenngee to Hautbois. A bit less cumbersome, if a bit more pretentious!)
Honestly, this graph would be much more depressing if we had data from 1750-1850. It looks bad compared to 1980-2010. Compared to 1750-1850 - one can only use their imagination.
Honestly, this graph would be much more depressing if we had data from 1750-1850. It looks bad compared to 1980-2010. Compared to 1750-1850 - one can only use their imagination.
Actually it would probably look less bad compared to 1750-1850.
There are enough indicators of how poor arctic sea ice is doing. Extent is just one of them. The drop in the amount of multiyear ice is perhaps even more alarming than extent. The MYI graph below is Jan 1999 to Jan 2017. Given recent data shared by A-Team, the amount of MYI is probably now even less than 2017.
3+ year old MYI has dropped by *90%*...Honestly, this graph would be much more depressing if we had data from 1750-1850. It looks bad compared to 1980-2010. Compared to 1750-1850 - one can only use their imagination.
Actually it would probably look less bad compared to 1750-1850.
There are enough indicators of how poor arctic sea ice is doing. Extent is just one of them. The drop in the amount of multiyear ice is perhaps even more alarming than extent. The MYI graph below is Jan 1999 to Jan 2017. Given recent data shared by A-Team, the amount of MYI is probably now even less than 2017.
Interesting.
It's difficult to comprehend that multi year ice has dropped by more than 50% in just 18 years.
A 2018 edition of the graph I put out a few times last year. The black dots are the maxima for previous years (timing and extent); the grey area is the extent range for each day. I'll update from time to time to the end of March.
Interesting is the range 2sd or something else?
To clarify: it's simply the difference, for each day (not including 2018), between the lowest extent and the greatest extent.
I don't think using the name of a musical instrument is pretentious at all!
I don't think using the name of a musical instrument is pretentious at all!
Well, in that case, I'm changing my name to Steinway! ;)
Or Stradivarius.....
I don't think using the name of a musical instrument is pretentious at all!
Well, in that case, I'm changing my name to Steinway! ;)
Or Stradivarius.....
I don't think using the name of a musical instrument is pretentious at all!
Well, in that case, I'm changing my name to Steinway! ;)
Or Stradivarius.....
those (Stradivarious & Steinway) are brands ;)
Oboe > Violin > Piano it would be then [Just Kidding]
I don't think using the name of a musical instrument is pretentious at all!
Well, in that case, I'm changing my name to Steinway! ;)
Or Stradivarius.....
or penny whistle
or triangle
I don't think using the name of a musical instrument is pretentious at all!
Well, in that case, I'm changing my name to Steinway! ;)
Or Stradivarius.....
or penny whistle
or triangle
I claim dibs on "spoons" !!!
Steve
At a time when the sea ice should be growing toward its maximum extent for the year, it's shrinking instead—the area of the Bering Sea covered by ice is now 60 percent below its average from 1981-2010.https://insideclimatenews.org/news/17022018/arctic-sea-ice-record-low-extent-alaska-bering-hunting-whales
"[Bering sea ice] is in a league by itself at this point," said Richard Thoman, the climate science and services manager for the National Weather Service Alaska region. "And looking at the weather over the next week, this value isn't going to go up significantly. It's going to go down." ...
NSIDC DATA as at 19th FebI wonder if this is the first time in history that area in Okhotsk has been above both Bering and Chukchi in February? (or any month?)
Arctic extent up by 85k to 14.023 million km2. Was the villain of the piece the Okhotsk Sea - offsetting Bering Sea extent loss ? Partly, but not wholly. See table below (daily Extent data from NSIDC)
to the point where we end up with actual MYI in Okhotsk, Baffin, and Labrador
lot of text, some graphs, very little on 2018 sea ice area and extent data
Watching winter sea ice used to be a bit boring. I don't remember a February like this, not even last year - a record low but not all this movement, fracturing and general - whatever.
I also had a look at annual averages for recent years - just to see the decline over time.
Looking at the average of the previous 365 days means as a new day is added, the day a year ago is taken out. Then the total s divided by 365 for the new annual average. So if today's extent is 365,000 km2 less than the extent on that date one year ago, the average drops by just 1,000 (one thousand) km2.I also had a look at annual averages for recent years - just to see the decline over time.
How's that simple average of previous 12 months graph looking now? I'm guessing it won't be great over the months ahead...
16 straight days of losses for Bering on NSIDC, down 55% from peak. In February. Will it stop?According to Wipneus's figures it just did:
Daily extent data from NSIDC said it didn't while the graphs said it did. Perhaps the graphs come from the NSIDC 5-day average data ?16 straight days of losses for Bering on NSIDC, down 55% from peak. In February. Will it stop?According to Wipneus's figures it just did:
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-regional.png
As did the rises in Okhotsk, Baffin, St Lawrence and Barents. Of course it may all just be a temporary reversal.
...Short of more crazy weather...
Hmm i don't understand how WACCy weather would lead to land masses shedding heat with the extra snow insulation impeding the escape of heat from the continents. Not sure it matters that much given how little heat the land stores relative to the oceans.
The elephant in the room here is of course that extent is lowest in core arctic seas and high in peripheral seas. Is anyone cumulatively plotting that and comparing it with previous years?Bear in mind the CAB also includes that area north of Svalbard that is typically open water in February in recent yeara. On top of that you have the newly open water north of Greenland, which is surely reflected in the numbers, but will hopefully refreeze before season's end.
Interesting to see this trend reflected in the CAB itself. Perhaps the lift off of ice from Greenland is beginning to show up in CAB extent. Short of more crazy weather, which it seems we'll be seeing a bit of a reprieve from, the recent losses in CAB extent should be recovered relatively quickly.
I think that the "Cold Continents" are only in comparison to the warm Arctic, and that they are warming up too -- just nowhere near as fast.
The CAB is pretty gobsmacking....
It looks from Wip's chart...for at least the years shown....that this would be the first "January max" (Assuming of course...that the Jan numbers hold). Other maximum's in the CAB looked to have happened in Feb or March.
And of course....one of these years.....we're going to get a double whammy of (1) an early start like this year, and then (2) a bad middle/end of year melt season. Just a matter of time... and the clock is ticking.
The CAB is pretty gobsmacking....
It looks from Wip's chart...for at least the years shown....that this would be the first "January max" (Assuming of course...that the Jan numbers hold). Other maximum's in the CAB looked to have happened in Feb or March.
And of course....one of these years.....we're going to get a double whammy of (1) an early start like this year, and then (2) a bad middle/end of year melt season. Just a matter of time... and the clock is ticking.
Overall, though, the tale so far has been one of highly unusual melt and warming. One that highlights the serious and worsening impacts of human-caused warming and related polar amplification.
I agree withQuoteOverall, though, the tale so far has been one of highly unusual melt and warming. One that highlights the serious and worsening impacts of human-caused warming and related polar amplification.
If I didn't, I would not be on this forum.
But Armageddon is still postponed (at least for a while?)
I think the real Armageddon (if it happens), would be in the summer. All we need is a bad summer to really destroy the ice. :(
I think the real Armageddon (if it happens), would be in the summer. All we need is a bad summer to really destroy the ice. :(
Both weather patterns, and sea and air temperatures are vastly different.
I think the real Armageddon (if it happens), would be in the summer. All we need is a bad summer to really destroy the ice. :(
All we need to really destroy the ice is for the Gulf Stream to decide to pass to the west of Greenland, and it won't matter what time of year. It is very unclear what is going on in the North-west Atlantic, but it isn't normal.
Open up a significant erea of hater inside of 80 north and you generate bottom water. That pulls the surface water north. Having the gulf stream go up the west side of Greenland is easy.I think the real Armageddon (if it happens), would be in the summer. All we need is a bad summer to really destroy the ice. :(
All we need to really destroy the ice is for the Gulf Stream to decide to pass to the west of Greenland, and it won't matter what time of year. It is very unclear what is going on in the North-west Atlantic, but it isn't normal.
Not so easy! First need to answer how the Gulf stream might possibly overtake/reverse the Labrador current with its 5 sverdrups.
https://en.wikipedia.org/wiki/Labrador_Current
Just watch what has been happening in the Gulf of Maine the last 5 years and ask the Lobstermen.Not so easy! First need to answer how the Gulf stream might possibly overtake/reverse the Labrador current with its 5 sverdrups.I think the real Armageddon (if it happens), would be in the summer. All we need is a bad summer to really destroy the ice. :(
All we need to really destroy the ice is for the Gulf Stream to decide to pass to the west of Greenland, and it won't matter what time of year. It is very unclear what is going on in the North-west Atlantic, but it isn't normal.
https://en.wikipedia.org/wiki/Labrador_Current
...But in a random chaotic system something as small as the flapping of a butterfly wing can turn into a hurricane... Or a GAC. Or two.
Please don't suggest non-physical things that violate the conservation of angular momentum.
But in a random chaotic system something as small as the flapping of a butterfly wing can turn into a hurricane... Or a GAC. Or two.
I wonder when our Guv'nor will feel the time is right to open the 2018 melting season threads. Can't be long.
I think 1 March should be declared the official opening day of the Melting Thread and 1 September the official opening day of the Freezing Thread. In the NSIDC record several years have already passed their maximums.I wonder when our Guv'nor will feel the time is right to open the 2018 melting season threads. Can't be long.
Probably 7-14 days from now, given that the AO is projected to strongly negative.
(A small aside: the NIPR CSV data now blanks out Feb. 29 data for non-leap years. It used to fill in those gaps, I think with the value from March 1. I like it better this way, but have they said anything about why they changed?)
Yeah, the leap day problem is a pesky one. To solve it for CT SIA, I had to convert all the dates to metric time. And still you get one line too many for complete uniform graphing for the data. I just split the difference over the whole year... But to be very accurate, technically, you'd need to start to number the datapoints of a year at six hour intervals on Metric time over the four year period. Thus you'd get staggered points of datevalues on graphs of several years. I figured that as I did not know the exact times of data acquisition, though the satellites orbit is very regular, this didn't matter. Anyway the fixed year+date/365 or date/366 made for prettier graphs at least with some illusion i knew what i was doing. And please don't ask me what to do about year 2100 which doesn't fit to the Julian calendar system.FAR TOO DIFFICULT for my Pooh-Bear Brain. Mind you, I got caught on March 1 when doing my semi-automatic transfer from the NSIDC spreadsheets to my copies - NSIDC does, of course have the Feb 29 line in all their data.
FAR TOO DIFFICULT
(clip)
FAR TOO DIFFICULT
(clip)
Yeah, I dropped the line too on some versions of the spreadsheet and worked it out as a puzzle to solve. The calendar system isn't too user friendly on science. Pmt on the evening of the day that ends at 12018.169863 (metric) of Holocene Era.
The Julian Calendar in Modern Society. Although the Gregorian calendar has become the international civil calendar, the Julian calendar was still used by some countries into the early 1900s. Some Orthodox churches still use it today to calculate the dates of moveable feasts, such as the Orthodox Church in Russia.
Seems to me if you wanted a rational dating scheme for the datatypes involved you'd want to tie it to the solar cycle (solstices, equinoxes, and the like) and completely ignore the Gregorian calendar -- but unfortunately, converting all the datasets to start on December 21 is beyond my pay grade.But the Equinox doesn't ALWAYS happen on December 21.
I wish I could snip February 29th once and for all. ;D
But yes, a bit more on-topic, s'il vous plait.
Regional Sea extent
Baffin down 25 k, Greenland up 23k, others not a lot of change, so where was the extent loss?
MEA CULPA
The regional numbers that you posted are based on 5-day running averages.
When I see ice enter Greenland I always say 'Tara!'
The same is true for Baffin ( it ain't running back up Nares and into the basin!)
The ragging peripheral areas has been seeing must lead to an amount of 'collapse and spread' before that ice thins to less than 15% cover and blinks out.
There is also the mixing of the waters at the ice edge as swells and waves do their work feeding a constant supply of warmer, saltier water to work on the ice now liberated?
Okhotsk, Baffin,Greenland and Barentsz are all one way tickets to oblivion for the ice.
We may see cold air over the central basin and that may lead to some thickening of the ice there but the peripheral areas will still be plagued by LP systems and ever warmer background temps.
We may see a very slow start to melt season though as , over past years, it was peripheral areas that made up initial losses? This year we are low on peripheral ice ( apart from Baffin/Okhotsk) so losses will be slow until the main basin melt kicks in?
PIOMAS update - "Wherefore Art Thou, PIOMAS".
PIOMAS update - "Wherefore Art Thou, PIOMAS".
PIOMAS = Pan-Arctic Ice Ocean Modeling and Assimilation System, so that's why (aka wherefore) PIOMAS, but, "What's in a name?" A rose by any other name would have the same total ice volume.
Or did you mean "where"? :)
I was being lazy, using it when knowing that it is a common misconception of the meaning. Unfair of you to pick me up on it, so "Lay off, MacDuff!"
Gerontocrat, in calculating potential rises for the table, are you also looking at years that went up somewhat but have not reached a new maximum? I am specifically asking about the yellow line of 2015.
Beware the false Max!!
Just for laughs ??? I thought I'd look over the last 10 years to see how often there was a 'cheeky peak' that might have got people thinking 'we've hit maximum', followed by a dip, and then followed by another peak that turned out to be the real maximum.
There were 5 that did that, and a sixth that nearly did, but not quite.
2008: 14.75m sq.km on day 62, lost 76k, then gained 100k.
2010: 14.651 on day 68, then lost 180k, then gained 217k
2011: 14.108 on day 67, then lost 181k, then gained 200k
2013: 14.513 on day 60 (March 1st, people), then lost 207k, then gained 217k.
2014: 14.255 on day 65, then lost 240k, then gained 433k as if to say 'haha just messin' with ya'
The 'not quite' year was 2012 - it dropped 199k, then gained 183k, so peak 2 wasn't quite the max in the end.
The 10 years before that were less tricksy. There were only three false max years; 1999 and 2003 stand out, overturning drops of 307k and 258k respectively from an initial false max.
(Now, what was I meant to be doing....)
Bering down 61k in fivedays,
Gerontocrat, I am suddenly not sure... Is your regional data from JAXA, NSIDC, or a combination?
What are the chances of JAXA SIE going over 14 million km2?
JAXA extent on March 15th is 13,875,677 km2, yet another new maximum for the year . Extent is fourth lowest for the day, greater than 2015 by 151k, 2016 by just 1k , and 2017 by 58k.
No that it is very important, but on March 15th, the year 2018 is the fifth lowest. 2006 is also below 2018.
March 15 vs. 2018
2018 13,875,677
2006 13,874,040 -1,637
2015 13,724,438 -151,239
2016 13,874,820 -857
2017 13,818,067 -57,610
P.S. And there is still some anomaly cold weather on the following days... ;)
What I note actually is (1) how close all the numbers are and (2) the serious observed differences in ice quality and distribution.
No that it is very important, but on March 15th, the year 2018 is the fifth lowest. 2006 is also below 2018.
March 15 vs. 2018
2018 13,875,677
2006 13,874,040 -1,637
2015 13,724,438 -151,239
2016 13,874,820 -857
2017 13,818,067 -57,610
P.S. And there is still some anomaly cold weather on the following days... ;)
Well spotted JCG,
The longer the 2018 freezing season lasts, the more of the previous years were in melting season, and 2018 could slip further down the table. While the Arctic as a whole looks like staying obstinately cold, maybe at the periphery sufficient warmth and insolation will end the season by the equinox, or maybe not.
Is this it ? Will Neven pull the lever and let the 2018 melt comments flood out?
As already reported by JCG elesewhereElsewhere would be here?
...
Is this it ? Will Neven pull the lever and let the 2018 melt comments flood out?
As already reported by JCG elesewhere, JAXA extent on March 18th is 13,833,573 km2, which may very well mean that the max on11th17th March of 13.891 million km2 was the 2018 maximum. This would mean 2018 comes in a t no #2 record low maximum.
Hi!
On march 17th, JAXA 2018 register 13,891,190 km2, which is now the max for 2018.
Also, it is 12,903 km2 above the 2017 max, so 2018 is not the lowest on record anymore. But it is still under the 2015 and 2016 max, so 2018 is now the second lowest max on record.
On march 18th, JAXA 2018 register 13,833,573 km2, an important drop of 57,617 km2. In my opinion, it starts to be difficult to have a max above 2015 (13.94M km2), that now it is the third lowest on record.
Congrats Neven! Max on March 17th! And also on the range you voted! ;)
We just have to wait some days, to confirm the max and open the melting season thread.
PS: At least 2 times on the year, I become addicted to JAXA! Please give me my daily dosis, JAXA! ;D
meanwhile the dmi 80 temps almost touch the long term average for the date ..
Hi gerontocrat!
It is 17th, not 11th...As already reported by JCG elesewhere, JAXA extent on March 18th is 13,833,573 km2, which may very well mean that the max on11th17th March of 13.891 million km2 was the 2018 maximum. This would mean 2018 comes in a t no #2 record low maximum.
Hi Juan - this getting to be an embarassingly regular occurrence. I am not checking me data properly. So thanks for the correction(s).
Meanwhile, NSIDC data will tell us where the extent loss is happening and maybe put even more pressure on the Guv'nor to open the floodgates of the melting season thread.
Meanwhile, NSIDC data will tell us where the extent loss is happening and maybe put even more pressure on the Guv'nor to open the floodgates of the melting season thread.
Little Hansje Brinker shouts: Wednesday! ;)
(https://www.aaenmaas.nl/binaries/twocolumn/content/gallery/am---website/common/informatie+op+maat/kinderen+0/kinderen/kids/hansjebrinker.jpg)
I was told Little Hansje Brinker was drowned in the flood, and his Mum said, " I kept on telling him to stop shoving his finger into that damn dyke, but he would not listen".
Simple...but not dumb...question: How can we be switching to melt mode when the temps up there are the frigidest of the season???Because the arctic is not a single location. The southern periphery is already melting while the inner areas continue freezing up until May.
http://ocean.dmi.dk/arctic/plots/meanTarchive/meanT_2018.png
Simple...but not dumb...question: How can we be switching to melt mode when the temps up there are the frigidest of the season???
http://ocean.dmi.dk/arctic/plots/meanTarchive/meanT_2018.png
It seems Bering has just almost made a new high, following Feb 7th which was at 411.5k, indeed a very strange year.extent+lower volume=stranger+stranger ;)
.... the dmi 80 temps almost touch the long term average for the date ...The existent Present High Arctic Berserker 8)(2), PHAB 8)(2) or FAB 8)(2) (continuous over-temperatures on the High Arctic) has died. FAB 8)(2) did exist for 215(+?) days, second only to FAB 8)(1) which existed for 231+ days from latter 2016 into 2017. Maximum days of continuous over-temperatures on the High Arctic in the latter 1950's & early 1960's lasted about 30 to 40 continuous days.
JAXA March 21st: 13,721,567 km2. A small increase of 8,514 km2.
2018 is the second lowest on record. 2015 is above by 16.8K km2. 2017 is 180.7K km2 under 2018.
Just to add that JAXA extent could easily be third lowest, above 2017 and 2006 tomorrow.JAXA March 21st: 13,721,567 km2. A small increase of 8,514 km2.
2018 is the second lowest on record. 2015 is above by 16.8K km2. 2017 is 180.7K km2 under 2018.
JAXA March 22nd: 13,711,450 km2. A drop of 10,117 km2.
Taking into account that yesterday had an increase of 8,514 km2, we can conclude that the change of March 20th to March 22nd is a little drop of 1.6K km2.
Just to add that JAXA extent could easily be third lowest, above 2017 and 2006 tomorrow.
The existent Present High Arctic Berserker 8)(2), PHAB 8)(2) or FAB 8)(2) (continuous over-temperatures on the High Arctic) has died. FAB 8)(2) did exist for 215(+?) days, second only to FAB 8)(1) which existed for 231+ days from latter 2016 into 2017. Maximum days of continuous over-temperatures on the High Arctic in the latter 1950's & early 1960's lasted about 30 to 40 continuous days.Tho FAB 8)(2) has ended after existing for 215(+?) days, with present High Arctic temperatures dipping below the average temperature line, the dip appears to be brief. Already the average High Arctic temperatures have bottomed & are again above the average temperature line. It appears that southern heat from eastern siberia is heating its way into the High Arctic & even to the North Pole & may do so for at least the next 5 days.
JAXA Actual Outlook:Hullo Juan,
2006 is the lowest today, but 2016 is going to take the lead, at the end of March.
I expect that 2018 can take the lead of lowest on record for a few days, and hope that 2018 will not follow 2016 afterwards.
Last year the ice was in rotten shape and there wasn't much of it. The cool stormy cloudy July saved the day. it may be that summers are getting stormier as open water increases in the Arctic. However, I wouldn't bet that this July will be as cool as last July.
I'm trying to understand how SSWs and ocean heat patterns might be used to predict summer weather. Wish me luck. So far, the models have shown limited predictive capabilities at seasonal time scales.
Tho the rising present High Arctic temperatures stopped ascending at only a few degrees Celsius above the average temperature line, the excess AGW siberian heat still pours into the High Arctic & High Arctic temperatures should strongly rise above the average.The existent Present High Arctic Berserker 8)(2), PHAB 8)(2) or FAB 8)(2) (continuous over-temperatures on the High Arctic) has died. FAB 8)(2) did exist for 215(+?) days, second only to FAB 8)(1) which existed for 231+ days from latter 2016 into 2017. Maximum days of continuous over-temperatures on the High Arctic in the latter 1950's & early 1960's lasted about 30 to 40 continuous days.Tho FAB 8)(2) has ended after existing for 215(+?) days, with present High Arctic temperatures dipping below the average temperature line, the dip appears to be brief. Already the average High Arctic temperatures have bottomed & are again above the average temperature line. It appears that southern heat from eastern siberia is heating its way into the High Arctic & even to the North Pole & may do so for at least the next 5 days.
Have we all been lulled into a 'high solar activity' calm of cloudy cool summers only for 'low solar ' to shake us out of the lull?Last year the ice was in rotten shape and there wasn't much of it. The cool stormy cloudy July saved the day. it may be that summers are getting stormier as open water increases in the Arctic. However, I wouldn't bet that this July will be as cool as last July.
I'm trying to understand how SSWs and ocean heat patterns might be used to predict summer weather. Wish me luck. So far, the models have shown limited predictive capabilities at seasonal time scales.
IMHO, the relatively cooler, cloudy summers we are seeing will become a persistent feature of the Arctic, due to reduced maximums, expansive open water and wobbly jet stream resulting in intrusions of moist air from the mid latitudes and locally generated cloud formation from evaporation. Difficult to say what the long term effects on summer melting seasons will be as the increased IR down welling caused by clouds and, likely, increased rainfall could counteract the reduced insolation.
At least during the melting season, the Arctic desert is disappearing.
Have we all been lulled into a 'high solar activity' calm of cloudy cool summers only for 'low solar ' to shake us out of the lull?
It's been pretty clear around Svalbard since early March due to the northern high pressures the SSW helped keep in place. how long will this North Atlantic propensity toward High pressure persist/ will we slip again into cloudy/cool conditions as the sun rises or will whatever drives the propensity for northern blocking patterns transfer ever higher into the basin?
I hope it isn't going to pan out but this is the first of the proper 'low solar' years so the next two will probably be 'stronger' in their low solar forcing?
Any move toward high solar over the ice in early melt season will feed my fears that this is what can drive a 'perfect melt storm' synoptic with the last 3 seemingly at the low solar end of the forcings ( as opposed to 'high solar' activity)
We are not as secure with our ice as we were back in 07' so even a partial 'perfect melt storm' season would lead us into problems?
Have we all been lulled into a 'high solar activity' calm of cloudy cool summers only for 'low solar ' to shake us out of the lull?
Can you point me towards research that confirms that solar cycles are responsible for changes between "cloudy" and "sunny" weather in the Arctic?
Can you point me towards research that confirms that solar cycles are responsible for changes between "cloudy" and "sunny" weather in the Arctic?
QuoteCan you point me towards research that confirms that solar cycles are responsible for changes between "cloudy" and "sunny" weather in the Arctic?
Do it somewhere else, please.
In fact, I am concerned about the end of March forecast.Right now the entire High Arctic temperature has rebounded from a temporary sub-average temperature to its present 4degC above average. A relative small eastern Siberian region of heat is feeding into the High Arctic. However, a vast line of excess AGW heat from northern Africa to China may also be supporting the eastern Siberian heat flow to the High Arctic. It is this present Africa to China heat(which was positioned further north) that supported the continuous 215 days of High Arctic temperatures of the past winter, the Present High Arctic Berserker(2) or FAB 8)(2).(+3.5°C ?):(
Edit 2:
I was sure that I saw the 3.5°C on the Arctic.
It is until April 1st. Hope it change to a lower anomaly.
[See 2nd image]
Soon to be 4th lowest.
Thank you for your early updates, JCG.
I am not sure that I will be able to do it all nights (for me ;) ), so if someone can try to do it also, that will be good. I will check if someone did it, before I do it.
The important thing is to have it right away!
Jim.... your graphs & details are spectacular. Your decade decreases in Arctic sea ice Volumes, even betters your spectaculars, tho.I am not sure that I will be able to do it all nights (for me ;) ), so if someone can try to do it also, that will be good. I will check if someone did it, before I do it.
The important thing is to have it right away!
FWIW, I maintain a similar graph for both IJIS and NSIDC extent over at my climate graphs site (https://sites.google.com/view/pettitclimategraphs). If you ever need a day or two off, everyone feel free to see my versions:
IJIS (Click for larger image):
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fiwantsomeproof.com%2Fextimg%2Fsie_six_week_detail.png&hash=fe0acbe1355895129edf6fae57c065aa) (http://iwantsomeproof.com/extimg/sie_six_week_detail.png)
NSIDC (Click for larger image):
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fiwantsomeproof.com%2Fextimg%2Fsie_nsidc_six_week_detail.png&hash=daed5fdc1da70674f1a8b83169859375) (http://iwantsomeproof.com/extimg/sie_nsidc_six_week_detail.png)
Images are updated on the server every day around 1200 UTC.
FWIW, I maintain a similar graph for both IJIS and NSIDC extent over at my climate graphs site (https://sites.google.com/view/pettitclimategraphs). If you ever need a day or two off, everyone feel free to see my versions:
...
Images are updated on the server every day around 1200 UTC.
April 3rd, 2018: 13,418,227 km2. A drop of -137,389 km2.Wow. That came out of the blue.
2018 is now the lowest on record! :P
April 3rd, 2018: 13,418,227 km2. A drop of -137,389 km2.Wow. That came out of the blue.
2018 is now the lowest on record! :P
That drop that was reported today, was the largest March drop in the 2005-2018 period. I wonder if there will be a rebound tomorrow...Intetesting that NSIDC reports a similar daily drop.
That would tend to argue against a rebound tomorrow....if I understand correctly that these are different data.That drop that was reported today, was the largest March drop in the 2005-2018 period. I wonder if there will be a rebound tomorrow...Intetesting that NSIDC reports a similar daily drop.
April 3rd, 2018: 13,418,227 km2. A drop of -137,389 km2.Wow. That came out of the blue.
2018 is now the lowest on record! :P
I agree. I think we will see massive continued sustained declines as the fake ice a la 2012 gives out even earlier than that year (with substantially more heat bubbling into Beaufort and Chukchi as we speak).April 3rd, 2018: 13,418,227 km2. A drop of -137,389 km2.Wow. That came out of the blue.
2018 is now the lowest on record! :P
not really, i had some post in reply to SharedHumanity 7-8 days ago but still there is never a guarantee that things go the way we thought ;) it's just that okhotsk as well as some other regions were quite green and yellowish for quite a few days on the UniBremen maps. and so much south there must be some significant solar impact by now.
i rebound for above reasons is not probable, no cold spell in those regions and the now increased area of open water will certainly catch a fair share of sunlight, albedo is dropping
That drop that was reported today, was the largest March drop in the 2005-2018 period. I wonder if there will be a rebound tomorrow...I have an IJIS drop of 169382 on Mar 23 2014. Making this the second biggest drop to date.
That should be 'largest April drop'.And a drop of 154512 on April 10 2004 makes it the second biggest drop in April. It does rate as the third biggest drop prior to June 1st.
Surprisingly, instead of a correction we have another small drop:
13,387,430, down 30,797 from yesterday's 13,418,227, and still at 1st place slightly below 2016.
How do you get that big difference in the the average 1980 and 1990 data ? Is it because they exclude/include some area's in the periferhy ?
Jim wrote "CLICK FOR LARGER AND MOST-RECENT IMAGE]". When I don't click on the image, I definitely see an old image.
How do you get that big difference in the the average 1980 and 1990 data ? Is it because they exclude/include some area's in the periferhy ?
How do you get that big difference in the the average 1980 and 1990 data ? Is it because they exclude/include some area's in the periferhy ?
Edit: Maybe as the satellite gets an equipment with better resolution, the sea ice extent gets a lower value. Kind of implicit when the definition is: "If sea ice on a grid is equal or more than 15%, then it becomes 100%". As the grid gets smaller, the rounding becomes smaller also.
My question was about the diffrence between the JAXA end the NSIDC. But i explained myself pretty bad. With the JAXA you see a clear trend , the 1990 average is half a million below the 1980 average. And if you look at the NSIDC , at some days the 1990 average is above the 1980 average.
The 1980s average in Jim Pettit's graph (https://i.imgur.com/b2EObWT.png) for NSIDC extent is wrong. In the official NSIDC Charctic (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/) graph, the 1980s average is always higher than the 1990s average.
Maybe it's the pole hole?
maybe Jim Pettit is also excluding 1980What I mean is that 80's average sometimes means 1980-89 and sometimes means 1981-90. So I am not sure what average is Jim making. On the other hand, the NSIDC 80's average has 12 years, because they explicit put it as 1979-1990 (it should included 79,80 and 90).
For the record, it was indeed a legitimate screw-up on my part...
Thanks, folks! The comments of several forum users led me to look into a small number of my graphs, and that in turn allowed me to hunt down and snuff out a data error that's gone undetected for several months.
For the record, it was indeed a legitimate screw-up on my part, a recently-introduced calculation error on a single range of cells on a spreadsheet that contains tens of thousands of them. More precisely, I'd previously been pulling older NSIDC extent data from one web-based source, but changed that last summer when I became aware of an easier-to-access, and more frequently-updated, source. In doing so, I inadvertently--and erroneously--neglected to update a formula in that range of cells that referenced the previous data; hence the incorrect 1980s average. Luckily, that cell was only reflected on a total of three graphs. And, luckily, that column and those graphs have now been updated. (And I've added +/-2 standard deviation shading to the graph in question.) (http://iwantsomeproof.com/extimg/sie_nsidc_six_week_detail.png)
I maintain dozens of graphs, each of them based on one or more spreadsheets, with each spreadsheet itself based on sometimes multiple data sources. Complicating matters, those data sources change: different baselines, enhanced algorithms, anti-biasing tweaks, and so on, and so forth. The result is that keeping on top of all those changes can be a frustrating task for graph creators--and that can lead to obvious frustration by those who use those graphs. So for that, I apologize. Mea maxima culpa. (That's Latin for "my bad".)
For what it's worth, in the future, a direct message or an email (my address is right on the graphs) will almost always get a quicker response, as I don't monitor this forum 24 hours a day. However, if you're the type of person who prefers jumping up, pointing your finger, and publicly shouting, "You're wrong!!!", by all means knock yourself out; I'll respond to those eventually, too. :)
Thanks again.
The pole hole is assumed 100% covered in ice (extent and area)?I have not follow area since Cryosphere Today stopped publishing. A shame, because I like area more than extent.
4.2.3 Arctic Pole Hole
4.2.3.1 Relevance of the Arctic Pole Hole to Ice Extent and Ice Area Values
...
The holes are significant because, in calculating Northern Hemisphere ice extent, it is assumed that the entire region under the Arctic pole hole is covered by ice at greater than 15 percent concentration. In calculating Northern Hemisphere ice area, however, the region under the Arctic pole hole is not included.
http://nsidc.org/data/G02135 (http://nsidc.org/data/G02135)
[Page 37]
Table 8. Arctic Pole Hole Mask Sizes and Dates
Arctic pole hole Area (million km2)
SSMIS Arctic Pole Hole Mask, 0.029, January 2008 to present
SSM/I Arctic pole hole Mask, 0.31, July 1987 through December 2007
SMMR Arctic pole hole Mask, 1.19, November 1978 through June 1987
The pole hole is assumed 100% covered in ice (extent and area)?I have not follow area since Cryosphere Today stopped publishing. A shame, because I like area more than extent.
I was asked to clarify.Thank you Wipneus!
A quick look at NSIDC regional data and the map suggests the pole hole is entirely contained within the Central Arctic Ocean. Is that correct?Yes.
So indeed the area and extent numbers in the NSIDC spreadsheet are not consistent. If you add the following values to the area numbers you should be fine:QuoteTable 8. Arctic Pole Hole Mask Sizes and Dates
Arctic pole hole Area (million km2)
SSMIS Arctic Pole Hole Mask, 0.029, January 2008 to present
SSM/I Arctic pole hole Mask, 0.31, July 1987 through December 2007
SMMR Arctic pole hole Mask, 1.19, November 1978 through June 1987
We are waiting.
JAXA says extent has stalled in the last 2 days.
JAXA says extent has stalled in the last 2 days.
Are we about to see a century break in the next few days?
That is finally a more typical temperature pattern; although slightly colder in the central U.S., and warmer in eastern Europe.Those are high temps across the US/Canada... this is not a typical pattern. We are still at record continental SWE and it is 4/13.
I thought that was a time stamp plot with the current temperatures measured at the time posted.It is, but 18z is 2PM EST which is normally when the highs occur. I would also recommend avoiding the GFS for anything but short-range forecasts in parts of the Lower 48 removed from any sensible substantial snowcover.
JAXA April 17th, 2018: 12,985,833 km2. A drop of -66,375 km2.2018 is going to hemorrhage in Okhotsk, Baffin, Bering, Beaufort, and Chukchi over the next thirty days. I would not be surprised to see its lead expanded. 2016 had significantly more volume in the way of the Pacific -- 2018 is in very dire straits, especially ^.
2018 is the JAXA ASI extent lowest on record.
2016 [2nd lowest] is 73,303 km2 above 2018.
I wouldn't bet too heavily on Hudson Bay. Most of that ice is well under 2 meters, and what isn't is still going to be acutely vulnerable. Late season cold won't be enough to strengthen it against the coming melt.JAXA April 17th, 2018: 12,985,833 km2. A drop of -66,375 km2.2018 is going to hemorrhage in Okhotsk, Baffin, Bering, Beaufort, and Chukchi over the next thirty days. I would not be surprised to see its lead expanded. 2016 had significantly more volume in the way of the Pacific -- 2018 is in very dire straits, especially ^.
2018 is the JAXA ASI extent lowest on record.
2016 [2nd lowest] is 73,303 km2 above 2018.
The ATL side in Barentz may actually mask losses as melt is matched by import. But this will probably end by 6/1, at latest.
I do anticipate Hudson Bay will hold up phenomenally well this year, with some ice possibly even making it through summer. But that is still unlikely, and will probably lead to sustained drops in the very late season (late July/August instead of May/June).
I wouldn't bet too heavily on Hudson Bay. Most of that ice is well under 2 meters, and what isn't is still going to be acutely vulnerable. Late season cold won't be enough to strengthen it against the coming melt.JAXA April 17th, 2018: 12,985,833 km2. A drop of -66,375 km2.2018 is going to hemorrhage in Okhotsk, Baffin, Bering, Beaufort, and Chukchi over the next thirty days. I would not be surprised to see its lead expanded. 2016 had significantly more volume in the way of the Pacific -- 2018 is in very dire straits, especially ^.
2018 is the JAXA ASI extent lowest on record.
2016 [2nd lowest] is 73,303 km2 above 2018.
The ATL side in Barentz may actually mask losses as melt is matched by import. But this will probably end by 6/1, at latest.
I do anticipate Hudson Bay will hold up phenomenally well this year, with some ice possibly even making it through summer. But that is still unlikely, and will probably lead to sustained drops in the very late season (late July/August instead of May/June).
I think the extraordinary snow amounts across the Canadian Shield will serve to buffer HB against melt for the foreseeable future, as incoming heat loses potency/deposits as snow across either Quebec or Ontario. This will likely change by mid-May or early June at the latest, but I think it will be sufficient to postpone melt-out of HB by a similar duration of the postponement of Canadian snow melt (on the order of 1.5-2 months).Your "sense of snow" is generating very strange predictions, but I like it that they are presented clearly. I feel bad about it but I will again take the other side of your bet. HB has been extremely predictable these last few years - most of the melt occurs between mid-June and mid-July, as shown on Wipneus' graph. There is simply no way that melt-out of HB will be postponed by 1.5-2 months, and I predict it will arrive like clockwork on the same schedule, give or take a couple of weeks.
Any chance of leaving one thread for data. It is getting a little to much marching through "snow drifts" on every thread. ThanksDo you think ice melts without reason? I didn't post any maps. I posted analysis. If you find ignorance blissful I suggest putting me on ignore.
This snow thing might be interesting but it's annoying having it drift into the wrong discussions. How about putting it all in Land snow cover effect on sea ice (https://forum.arctic-sea-ice.net/index.php/topic,292.0.html) where it belongs?Any chance of leaving one thread for data. It is getting a little to much marching through "snow drifts" on every thread. ThanksDo you think ice melts without reason? I didn't post any maps. I posted analysis. If you find ignorance blissful I suggest putting me on ignore.
This snow thing might be interesting but it's annoying having it drift into the wrong discussions. How about putting it all in Land snow cover effect on sea ice (https://forum.arctic-sea-ice.net/index.php/topic,292.0.html) where it belongs?Any chance of leaving one thread for data. It is getting a little to much marching through "snow drifts" on every thread. ThanksDo you think ice melts without reason? I didn't post any maps. I posted analysis. If you find ignorance blissful I suggest putting me on ignore.
bbr .. 'you people' are your readership .. and abusing us is scarcely the way to bring us flocking to the Guru's feet . This thread is for data not arguments about what you think might happen (see title ! ). Some folks are even taking a holiday from posting as seeing every thread snowed on is no more beneficial than a forum filled with AGW deniers . Please review your methodology .. b.c.
What is off-topic about the above?!?!?!
Will do 8)What is off-topic about the above?!?!?!
This thread is about discussing area and extent data as it comes in, not about what is going to happen the next 30 days and how snow plays a major role in it.
Keep it short in the Melting Season thread, and do whatever you like in the NH snow cover thread. Shut up about snow over here.
2010's Average: April 28
2000's Average: May 4
1990's Average: May 13
1980's Average: May 21
edit: Looks like gerontocrat was faster than me, I'll leave the post up anyway.
JAXA ASI Extent.I 'Liked' this, Actually should for each one, but most times I come on it is more to see what is happening then quickly leave. Not very kind to the forum, but what value I can add is very bad from education standards. On the otherhand liking it leaves me with a very sick feeling, because the legacy my generation has left (over 55) the next many generations will be paying a very high price for their entire lifetimes.
April 19th, 2018: 12,888,393 km2, a drop of -50,285 km2.
2018 is the lowest on record.
2018 is now -39,724 km2 under 2016.
The Chukchi Sea region is still cold enough to resurface itself with ice when big open ocean areas form. This will stop soon, so I expect to see major drops in ice extent soon.The Chukchi and Beaufort are going to begin opening wide and clear within the next 10 days. It is going to be a sight to see! More like a zipper instead of a gradual march.
On the Atlantic side, zilch area loss on the 20th after a few days of modest losses in the Kara and Laptev for a few days before.
My regional postings are from NSIDC area - 5 day trailing average, which smooths daily data.
Is there any way for us to get some estimate of export into this section? How much is melting that is hidden in the lack of change in the extent?
The Chukchi Sea region is still cold enough to resurface itself with ice when big open ocean areas form. This will stop soon, so I expect to see major drops in ice extent soon.The Chukchi and Beaufort are going to begin opening wide and clear within the next 10 days. It is going to be a sight to see! More like a zipper instead of a gradual march.
The Chukchi Sea region is still cold enough to resurface itself with ice when big open ocean areas form. This will stop soon, so I expect to see major drops in ice extent soon.The Chukchi and Beaufort are going to begin opening wide and clear within the next 10 days. It is going to be a sight to see! More like a zipper instead of a gradual march.
Resurface with what? Nilas?The Chukchi Sea region is still cold enough to resurface itself with ice when big open ocean areas form. This will stop soon, so I expect to see major drops in ice extent soon.The Chukchi and Beaufort are going to begin opening wide and clear within the next 10 days. It is going to be a sight to see! More like a zipper instead of a gradual march.
Nothing short of nuclear war between Alaska and Eastern Siberia would put enough energy into the system to acheive this. It takes more than hot air to melt ice.
Chukchi and the Beaufort take about three months of steady decline to lose their ice. Over that period they will lose about 1 M km^2 in total; A rapid decline would be losing that in 10 weeks. or about 100K per week. I expect an unspectacular decline in May due to the lack of ice in the Bering with the extent being somewhere near the 2015 (10.8-11.0M) figure by May 31st.
Recovery!
I'm curious to see if we will get a century-drop tomorrow to compensate...
It looks like Hudson's bay will melt out early this year because the same weather that brought snow to eastern Canada helped bring in warm salty water that originated in the Gulf Stream and was advected around Iceland and Greenland into the Labrador sea. Labrador sea mixing went down to at least 2000m this late winter.
Ice is also melting rapidly offshore of the west coast of Greenland as the west Greenland current cranks up and advects heat northwards.
One piece of good news is that the weather has advected very little ice out of the Fram strait. There has been very little transport of ice out of the Arctic ocean all winter. The ice edge on the Barents sea has become the ice melting zone, but in the cold dark winter that's pretty good news for the ice.
Well you have me baffled guys! Looking at Worldview over the month of April, no ice has moved (been "entrained") into Hudson Bay or Hudson Strait. The ice shifts a bit one way and then another, but the main movement in Hudson Strait seems to be towards the south.It looks like Hudson's bay will melt out early this year because the same weather that brought snow to eastern Canada helped bring in warm salty water that originated in the Gulf Stream and was advected around Iceland and Greenland into the Labrador sea. Labrador sea mixing went down to at least 2000m this late winter.
Do you see the ice that seems to be getting entrained into Hudson Strait from Baffin Bay? It is thick, possibly multi-yr ice. I wonder how long it survives and if this is just a day or two blip or the start of something new.
JAXA Analysis:
It is possible that 2018 drops more than 54.1K km2 average on the next 11 days, so I do not discard that could continue been the lowest on record. But I see a big probability that the average drop will be more than 20.6K km2. So, I think that -at least- 2018 will be second lowest on record at the end of April.
Melting (and the reverse) seems to go in wavesYour chart clearly shows a (possibly random) wave pattern. Does the area chart show a similar pattern? It may be that the way extent is measured/calculated amplifies the waves.
QuoteMelting (and the reverse) seems to go in wavesYour chart clearly shows a (possibly random) wave pattern. Does the area chart show a similar pattern? It may be that the way extent is measured/calculated amplifies the waves.
QuoteMelting (and the reverse) seems to go in wavesYour chart clearly shows a (possibly random) wave pattern. Does the area chart show a similar pattern? It may be that the way extent is measured/calculated amplifies the waves.
QuoteMelting (and the reverse) seems to go in wavesYour chart clearly shows a (possibly random) wave pattern. Does the area chart show a similar pattern? It may be that the way extent is measured/calculated amplifies the waves.
Same here - there is a long term trend, and then a short periodicity on a wavelength of a few days that is likely to be the periodicity of weather changes. If someone wants to show me where the data is maybe a .csv, then I'll apply an FFT and maybe something will drop out.
The Bering Sea is a month in advance, and we are close to the lowest extent. Than their has to be a place that has more extent than normal. I have been looking on Nasa worldview. But the only place where there is more than the years before is west of the Kara Sea, near that long island. All the rest looks the same or less. North of Svalbard is big gap. The Ice in the Okhotsk Sea is almost gone. So where is that extra extent, or has it something to do with that 15 % ice cover.We are not at normal extent, we are far lower than normal, with only the abnormal 2017 and 2016 for company. But the best link for this question is Wipneus' AMSR2 regional page. https://sites.google.com/site/arcticseaicegraphs/regional (https://sites.google.com/site/arcticseaicegraphs/regional)
ADS NIPR JAXA, ASI Extent.Interesting how both 2017 and 2018 are currently running in parallel.
April 24th, 2018: 12,794,137 km2, a drop of -9,060 km2.
2018 is the second lowest on record.
2018 is 160,465 km2 above 2016 and 38,713 km2 under 2017.
| Total Area without Hudson and Okhotsk Date Area change Km2 18-Apr -24251 19-Apr -29493 20-Apr -24356 21-Apr 76 22-Apr 2531 23-Apr -190 24-Apr 12677 25-Apr 10548 26-Apr 5304 On any measure of extent or area NSIDC says the Arctic Ocean is having a mini(?)-break from the melting season. |
Wipneus has nice charts of Arctic Basin (as he defines it) area and extent on his website, I can post the link tomorrow if you can't find it.https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-area-multiprod.png (https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-area-multiprod.png)
Note at this time of year it's not very useful, it becomes much more interesting during summer.
Note the charts are still not updated for 2018.
| Total Area without Hudson and Okhotsk Date Area change Km2 19-Apr -29493 20-Apr -24356 21-Apr 76 22-Apr 2531 23-Apr -190 24-Apr 12677 25-Apr 10548 26-Apr 5304 27-Apr 2900 28-Apr 3416 On any measure of extent or area NSIDC says Arctic Ocean Area is having a mini(?)-break from the melting season at the moment. |
With all this stalling melt, a big drop seems likely right?
With all this stalling melt, a big drop seems likely right?
Hi, Wherestheice.
In my opinión, 2018 has not stall. 2016 was terrible on April and specially on May. So, it is pretty bad to be the second lowest on record.
Anyway, it is getting late for me and the JAXA data has not being updated yet. So, if anybody gets the information updated, please feel free to post it.
The link is: https://ads.nipr.ac.jp/vishop/#/extent (https://ads.nipr.ac.jp/vishop/#/extent)
Thanks!
With all this stalling melt, a big drop seems likely right?
Hi, Wherestheice.
In my opinión, 2018 has not stall. 2016 was terrible on April and specially on May. So, it is pretty bad to be the second lowest on record.
Anyway, it is getting late for me and the JAXA data has not being updated yet. So, if anybody gets the information updated, please feel free to post it.
The link is: https://ads.nipr.ac.jp/vishop/#/extent (https://ads.nipr.ac.jp/vishop/#/extent)
Thanks!
Yes that makes sense. Thanks for reply!
As I have dealings with the Japanese stock market, I happen to know that today is a holiday in Japan, so quite possibly there will be no data release today.
The same could happen on Thursday/Friday/Saturday this week, as all of these are national holidays as well.
Hi. Just checked ADS_NIPR on Twitter and found this tweet:I hope it is more to do Japan's Golden Week of holidays and they've gone to the beach or the park or.....
ADS_NIPR @ADS_NIPR · 5h5 hours ago
5月1日から2日までメンテナンスを実施するためADSのサービスは停止いたします。
ADS services is stopped to do H/W maintenance from May 1st to 2nd.
https://twitter.com/ads_nipr
Note the charts are still not updated for 2018.Fixed :)
It is May 1st and I am not out there protesting against something. Shame.
Hi. Just checked ADS_NIPR on Twitter and found this tweet:I hope it is more to do Japan's Golden Week of holidays and they've gone to the beach or the park or.....
ADS_NIPR @ADS_NIPR · 5h5 hours ago
5月1日から2日までメンテナンスを実施するためADSのサービスは停止いたします。
ADS services is stopped to do H/W maintenance from May 1st to 2nd.
https://twitter.com/ads_nipr
Dedication to duty can be overdone.
The northern hemisphere sea-ice extent (or volume) doesn't matter.
Only the Arctic Ocean sea-ice extent matters.
The northern hemisphere sea-ice extent (or volume) doesn't matter.
Only the Arctic Ocean sea-ice extent matters.
There could still be ice in Baffin Bay, CAA, and others, when the Arctic Ocean starts to warm up due to loss of albedo. A lot of talk is about 'lowest' or '2nd lowest'. So the lowest Arctic Ocean extent may be telling us something that the northern hemisphere extent is not. I'm talking about the overall picture of ice extent, not animals and people. That is a different topic. I'm asking the question, could a disaster unfold in the Arctic Ocean extent, even if the northern hemisphere extent is in 2nd or 4th place for the time of year? If blue ocean extends even a little more than usual in the Arctic Ocean, I'm hoping that the heating effect does not come to a tipping point in the ocean, or something more like exponential heating.The northern hemisphere sea-ice extent (or volume) doesn't matter.
Only the Arctic Ocean sea-ice extent matters.
There is 1.4 million km2 of open ocean on May 2 receiving a strong dose of solar radiation where in the 1980's there was ice-covered ocean. (In 2016 it was 1.8 million km2.) This is a positive feedback mechanism for increase in ocean heat content.
While the peripheral seas are ice-covered this inhibits the transfer of heat into and the effect of wind/wave action on the CAB.
Sea ice extent in the periphery certainly matters to polar bars and walruses, whales, orcas, etc who are moving into regions that were ice-covered.
Sea ice extent in the periphery certainly matters to the humans watching their shores eroded and their livelihood changed forever due to earlier sea-ice melt.
So I, for one, will continue to take a keen interest in changes to extent, area, and volume for the Arctic as a whole and individual seas within it (including the timing and extent of sea-ice loss in the central seas of the Arctic Basin as a whole and individually).
"NSIDC Total Area as at 2nd April.(5 day trailing average)"Whoops! Thanks - methinks I had better slow down - or stop.
Don't you mean May?
Just a little proposal to move "Hudson Bay" into the peripherical seas table so both tables have the same number of columns, and Hudson Bay is quite far away from CAB.
Just a little proposal to move "Hudson Bay" into the peripherical seas table so both tables have the same number of columns, and Hudson Bay is quite far away from CAB.
I am thinking of parking both Hudson Bay and the Okhotsk Sea to one side as they are so physically separate from the main Arctic Ocean.
The Bering Sea is important - being the plug inhibiting warmth, waves etc entering the main Arctic Ocean. How quickly that plug is removed matters, which is why it needs to stay.Just a little proposal to move "Hudson Bay" into the peripherical seas table so both tables have the same number of columns, and Hudson Bay is quite far away from CAB.
I am thinking of parking both Hudson Bay and the Okhotsk Sea to one side as they are so physically separate from the main Arctic Ocean.
Add Bering, as it is functionally just a buffer that prevents early melt in the Arctic Proper... But your human health first, of course. These are hard times with people talking of f.e. healthy economy as if economy could have diseases. ::) ;) 8)
There is something very striking about the conversation here tracking the beginning of the melt season. When I 1st came here, the conversation was about cloudless high pressure, insolation and melt ponds. We now talk about warm weather intrusions and 2m temperature anomalies.
I don't know that this is a good thing.
But then again, abrupt sea ice loss can turn around into abrupt sea ice gain.Gain at this point in the Barentzs isn't necessarily a good thing, as probability indicates, it will all be gone by the end of the melt season.
There is something very striking about the conversation here tracking the beginning of the melt season. When I 1st came here, the conversation was about cloudless high pressure, insolation and melt ponds. We now talk about warm weather intrusions and 2m temperature anomalies.
I don't know that this is a good thing.
[ADS-NIPR-JAXA] ASI Extent.
May 8th, 2018: 12,077,941 km2, a drop of 37,551 km2.
2018 is the second lowest on record.
2018 has 295,775 km2 more than 2016 and 73,643 km2 less than 2006.
I'm not clear exactly what you're plotting here, a figure legend would help. Thanks.[ADS-NIPR-JAXA] ASI Extent.
May 8th, 2018: 12,077,941 km2, a drop of 37,551 km2.
2018 is the second lowest on record.
2018 has 295,775 km2 more than 2016 and 73,643 km2 less than 2006.
And with that 2004 loses its' last day in the top 3 for any day of the year. 2005 will stay in the list until Feb 6th when its sole day in the top 3 occurs.
2012 doesn't get a lowest 3 day until June 11th and if current trends continue 2018 will have more days in the lowest 3 by June 10th than 2012 has in the entire year.
Does somebody knows how much ice the Bering Sea normaly loses at this time of the year ?10-15 thousand km2/day. (https://sites.google.com/site/arcticseaicegraphs/regional)
I'm not clear exactly what you're plotting here, a figure legend would help. Thanks.Hope this helps, Its a bar chart of the number of days rated in the lowest three in the IJIS Arctic Extent record.
[ADS-NIPR-JAXA] ASI Extent.
May 9th, 2018: 12,021,992 km2, a drop of 55,949 km2.
May 10th, 2018: 11,933,172 km2, a drop of 88,820 km2.
2018 is the second lowest on record.
On May 10th:
2018 has 299,829 km2 more than 2016 and 151,697 km2 less than 2006.
Yes - 'tis the Arctic. Within the Arctic Sea Ice Section you will find the topic "Global sea ice area and extent data" that combines N & S.[ADS-NIPR-JAXA] ASI Extent.
May 9th, 2018: 12,021,992 km2, a drop of 55,949 km2.
May 10th, 2018: 11,933,172 km2, a drop of 88,820 km2.
2018 is the second lowest on record.
On May 10th:
2018 has 299,829 km2 more than 2016 and 151,697 km2 less than 2006.
is this northern hemisphere only thread, not according to the title and globally we're lowest.
Nope. I showed 2012 because it was unique in moving from above average extent in April to a record low in September. No other year has shown such a rapid change. To me it demonstrates both the unpredictability of a melting season at the beginning, and also the limit of that unpredictability. That limit tells me to forget a Blue Ocean Event this year.
Any chance of including 2007 in the graph as that was a low one too - certainly shows 2012 standing out with a very rapid increase over the next couple of months.
I think what you see standing out is 2016, which started the melting season with extreme losses and had the potential to become lowest on record, but was saved during June and July. Even eith that, it finished not far behind 2012 in area, and I believe its lead in albedo-warming potential played a significant part in that.
Any chance of including 2007 in the graph as that was a low one too - certainly shows 2012 standing out with a very rapid increase over the next couple of months.
I think what you see standing out is 2016, which started the melting season with extreme losses and had the potential to become lowest on record, but was saved during June and July. Even eith that, it finished not far behind 2012 in area, and I believe its lead in albedo-warming potential played a significant part in that.
Neven - I have a small request. This thread is the first one I go to when on the forum. It would be nice if it could be bolded, like the late IJIS thread used to be.
Just fix the recurring typo, 2012 was more on this date, not less...
While area is lower than every year except for 2016, it seems the timing of the onset of serious melting is similar to most years on the chart.It depends on which bit of the Arctic you look at, so here goes:-
One point about the CAB, in reality it is bunch of areas that have different ice melt characteristics. In general, it would be best if NSIDC decided to split the CAB into several sub-geographies, with reprocessing of past regional data, as rapid changes in a small sub-area are masked by bundling into the CAB super-area.
Just to complete the discussion, this is the map used by Wipneus for the AMSR2 regional graphs, based on the Cryosphere Today mask. In this map the CAB is larger than on the NSIDC map, with the Beaufort, Chukchi, ESS and Laptev all smaller, and also a slightly different cutoff at the Fram.
Just to complete the discussion, this is the map used by Wipneus for the AMSR2 regional graphs, based on the Cryosphere Today mask. In this map the CAB is larger than on the NSIDC map, with the Beaufort, Chukchi, ESS and Laptev all smaller, and also a slightly different cutoff at the Fram.I am confused again - so please remind me which is the goddam NSIDC map.
Just to complete the discussion,
Thus far, 2018 has been roughly paralleling the melt years of 2009, 11, and 15. Those years finished 11th, 4th, and 5th lowest minima respectively, after reaching 10th, 5th, and 3rd highest maxima. That pace, should it continue, would place 2018 at 4th lowest.For me, quasi-statistical estimations based on graph morphology like this have failed miserably every time I've made one. Based on that, the only guess I'll hazard at this juncture is the season will finish somewhere between 1st and 10th lowest minima. 😁
quasi-statistical estimations based on graph morphology
Quotequasi-statistical estimations based on graph morphology
Thanks for that. I tend to do this a lot. Your description of the method really puts in perspective for me.
That is about the best we can do. Any individual year can have idiosyncrasies that lead to a much higher or lower minimum than expected otherwise. Currently, I would say we have a low probability of a 1st or 10st lowest minimum, and higher probability of landing in between. As the melting season proceeds, we can start eliminating other values, as being similarly unlikely. In the end, several factors will come together, resulting in the final measurement, leaving everyone scratching their heads as to why this year did exactly what it did.Thus far, 2018 has been roughly paralleling the melt years of 2009, 11, and 15. Those years finished 11th, 4th, and 5th lowest minima respectively, after reaching 10th, 5th, and 3rd highest maxima. That pace, should it continue, would place 2018 at 4th lowest.For me, quasi-statistical estimations based on graph morphology like this have failed miserably every time I've made one. Based on that, the only guess I'll hazard at this juncture is the season will finish somewhere between 1st and 10th lowest minima. 😁
Thus far, 2018 has been roughly paralleling the melt years of 2009, 11, and 15. Those years finished 11th, 4th, and 5th lowest minima respectively, after reaching 10th, 5th, and 3rd highest maxima. That pace, should it continue, would place 2018 at 4th lowest.
Any individual year can have idiosyncrasies that lead to a much higher or lower minimum than expected otherwise.Do you think 2018 or other near future years will return to the high Arctic sea ice extents & volumes of the average of the 1980's?
Not in 2018 or the near future. Eventually, yes.Any individual year can have idiosyncrasies that lead to a much higher or lower minimum than expected otherwise.Do you think 2018 or other near future years will return to the high Arctic sea ice extents & volumes of the average of the 1980's?
I agree. Possibly about 130 million years from now it may. Earth has roughly followed a 50million year glaciated, 100 million year ice free hothouse cycle for about the last billion years. The unprecedented in the last billion years rate of warming, and ecocide humans have achieved virtually guarantees that we have ended the recent 50 million year glacial. If we are lucky we may not have set off a Venus style runaway water vapour greenhouse warming. Let's cross our fingers and hope that near or all non photosynthetic life will be wiped out instead, and extremophile cyanobacteria put the earth in a snowball state for a hundred million years or so to reboot the ecosphere.Not in 2018 or the near future. Eventually, yes.Any individual year can have idiosyncrasies that lead to a much higher or lower minimum than expected otherwise.Do you think 2018 or other near future years will return to the high Arctic sea ice extents & volumes of the average of the 1980's?
And here are the regional area graphs.
Kara Sea: Stubbornly resisting melt early in the season.
I've always thought that comparing area to extent performance could reveal insights about the melt season but I don't see anything of note at the moment. Area and extent for the regions seem to be tracking closely.
I've always thought that comparing area to extent performance could reveal insights about the melt season but I don't see anything of note at the moment. Area and extent for the regions seem to be tracking closely.
According to Windy: forecast for Tuesday 3pm in Churchill has ECMWF at 15 C, GFS at 19 C, NEMS at 20 C.
The temperature gradient from inshore to the sea is very steep. In all three models you get mid-20s not far from Churchill. I presume there must not be much snow left inland (the rail line got wiped out by flooding in April last year, so that must be about when the snow largely melts).
With the following plateau in losses and the discussion re: AMOC crazy in the melt season thread, it is certainly an interesting development.
I've always thought that comparing area to extent performance could reveal insights about the melt season but I don't see anything of note at the moment. Area and extent for the regions seem to be tracking closely.
There is no need to suspect, as Worldview comes in handy. These are not melt ponds with their telltale bluish tinge. When leads open between floes, as is happening in mass in the Beaufort, sea ice concentration goes down. But with NSIDC's large grid of roughly 25 x 25 km, when concentration remains above 15% you get full extent but a reduction in area. Area is a leading indicator of extent at this time of year. Melt ponds and wet snow have much more influence in June-August.
Note: posting this here because of the data discussion. Can be developed further in the melting season thread.
"Beaufort is a laggard", but only by about 75,000Km2.No predictions - simply what is at 30th May. (A-team has posted in the melting season thread a super 31 day animation of ice in the Amundsen Gulf - and something is certainly afoot on the Pacific side).
That's not a lot to make up.
Just wanted to throw a quick word on Wipneus' regional charts, they are showing AMSR2 data, with much better resolution than NSIDC, and using Wip's "home brew" algorithm for filtering all kinds of wrong stuff from the data. So indeed unsuitable for your purposes due to lack of long history and due to being incompatible with NSIDC, but very useful for comparing recent years.
I expect an unspectacular decline in May due to the lack of ice in the Bering with the extent being somewhere near the 2015 (10.8-11.0M) figure by May 31st.
the fourth lowest is the 2010's average published by ADS NIPR. And 2018 is 254,489 km2 less than 2010's average.To clarify - that's the 2010-2017 average right? 2018 data hasn't been included in the average yet?
No that average includes 2018, if you leave 2018 out, 2011 scrapes in below the average and 2010 just misses out.the fourth lowest is the 2010's average published by ADS NIPR. And 2018 is 254,489 km2 less than 2010's average.To clarify - that's the 2010-2017 average right? 2018 data hasn't been included in the average yet?
NSIDC Area - Leaders and Laggards of ice loss by each regional sea (continued)
6) Hudson Bay and St Lawrence
Both are oddities.
Hudson Bay, despite its relatively low latitude (about 55 to 65) it is late to start. Damn cold for damn long in that part of Canada - not called "The Barrens" for nothing. Brrrr. High snow-fall and persistent cold meant a late start to melting (pace bbr 2314). Now catch-up taking place but still a laggard.
St Lawrence, at just 48 degrees north, is the smallest Arctic sea, a maximum of 150,000 km2 of sea ice. So it is sort of insignificant. It was slow to start melting due to the high snowfall and persistent cold, got ahead of the game and has now stalled at just over 10k sea ice area, i.e. a non-player.
6) Leaders 0, Laggards 1, Non-Players 1
b.fwd from last post Leaders 6, Laggards 4, Non-players 2
Overall Totals Leaders 6, Laggards 5, Non-players 3
But of them all, I guess that in the end what happens to the Central Arctic perhaps matters most.
You won't see this exercise again for some time - too much like hard work
_____________________________________
Explanatory Note:
I developed these graphs to look at the current year in comparison with 10 year averages from the 80s, 90s 00s, and the 2010's to date (2010 to 2017). This tells me if the current year is likely (or not) to drag down the 2010's average area and also give an idea of trends in ice-free days (5%, 15% and 50%).
I'd love to see the effect of Alberto on Hudson BayThe seven day Environment Canada forecast for Moosonee, at the edge of James Bay, calls for mostly sunny and temperatures in the double digits. I expect that there will indeed be melt ponds- and general melting. https://weather.gc.ca/city/pages/on-113_metric_e.html (https://weather.gc.ca/city/pages/on-113_metric_e.html)
NSIDC Area - Leaders and Laggards of ice loss by each regional sea (continued)
[...]
Worldview confirms what AMSR2 hints ... the north Kara Sea is now a bowl of ice cubes. The first image is a bit hazy in places, so I magnified the hazy portion, played with the contrast and the broken floes all the way out towards Svalbard are clearly visible. Maybe there is a little refreezing in there, but it can't last long.
On behalf of all, thank you again JCG and grntc for your timely data updates.You are welcome, Oren.
JAXA short term analysis - May 8th, 2018.JAXA short term analysis - June 5th, 2018.
...
So, it is almost sure that 2018 will be the second lowest on record, at least on the following two weeks.
The interesting question is where 2018 will be on June 10th, when the years 2010, 2011, 2012, 2015 and 2017 are even, on the second lowest on record position, while 2016 starts to lose the first lowest on record position.
That interdecile range doesn't look right. I count what looks like a quintile (8) rather than a decile (4) worth of data lines below it on some dates.
Days in the bottom 3, cumulative, from January 1 to May 31.
By the end of May, 2018 had only had 6 days that weren't. And had also just overtaken 2012's total for the year.
[ADS-NIPR-JAXA] ASI Extent.Looks like 2018 should go crashing through 2016 in the next few days as the cyclone accelerates this year past that year's June stall.
June 6th, 2018: 10,518,855 km2, a drop of -66,208 km2.
2018 is the second lowest on record.
2018 has 185,748 km2 more than 2016 and 70,481 km2 less than 2015.
The St Lawrence is interesting. No matter that area in winter is declining substantially over the years, the final collapse seems to be the first week in June regardless. The start of winter area gain seems also the same no matter what.
NopeThe St Lawrence is interesting. No matter that area in winter is declining substantially over the years, the final collapse seems to be the first week in June regardless. The start of winter area gain seems also the same no matter what.
It's alwayse "false ice" near shores detectes and 1 June is probably day when they remove that region from calculations at all.
| Date Area km2 May 31 14,515 June 1 12,839 June 2 11,008 June 3 6,079 June 4 3,644 June 5 1,880 June 6 1,720 June 7 936 |
JAXA Extent 10,482,795 km2（June 7, 2018）
GFS (from cci-reanalyzer) still shows large areas of the Arctic having had, getting, and will continue to get a dose of real warmth. I am increasingly surprised that the effect on extent data is still not obvious yet. Perhaps the effect on the seas in the CAB is more a case of thinning, fracturing and opening of leads rather than larger areas of open water.
83 cm of rain at 1C to will melt 1 cm of ice
The Arctic Basin is one of the driest parts of the Arctic. Most of the Basin receives less than 250 mm (9.8 in) of precipitation per year, qualifying it as a desert. Smaller regions of the Arctic Basin just north of Svalbard and the Taymyr Peninsula receive up to about 400 mm (16 in) per year (Serreze and Hurst 2000).
Monthly precipitation totals over most of the Arctic Basin average about 15 mm (0.59 in) from November through May, and rise to 20 to 30 mm (0.79 to 1.18 in) in July, August, and September (Serreze and Hurst 2000).
Daily amount of precipitation (measured once or twice
daily (at 0600/1800 h) and covering the previous 12/24 h
period) has been recorded continuously for multiple decades
at three manned weather stations in Spitsbergen (the largest
island on Svalbard, Stations 1–3, figure 1(a)): the small
research settlement Ny-Ålesund (population ∼30 year-round;
Norwegian Meteorological Institute, data available at http://
eklima.no), the Russian settlement of Barentsburg (population
∼435; data available at www.tutiempo.net/en/Climate/
BARENCBURG/07-1973/201070.htm), and Svalbard Airport.
At all three weather stations, several heavy rainfalls were
associated with the two-week warm spell (figure 1(c),
table 1). The most striking event was recorded in Ny-Ålesund
on January 30th when 98 mm rain fell (Tmax = 4.3 °C), which
had (prior to this event) a return period of >500 years following
the Norwegian manual for calculation of probable
extreme daily precipitation values (Førland 1992),
Off-Topic alert. Reminding this is the extent and area thread.
Cyclones cause dispersion of ice. Stormy Junes are generally good for ice. Because this storm hit its max intensity over open water in the Barents sea it advected a warm sector over the Laptev sea causing warm offshore winds and melting so it doesn't fit the general mold of June storms. It very likely caused a large amount of melting. However, the dispersion it caused offset the drop in sea ice extent in the Laptev sea.
Any time there's a large shift in wind direction in the Arctic's melt season the rate of decline in extent slows down.
Because of dispersion this warm storm caused a volume drop but not an extent drop.
<em> In total, area loss is still consistently ahead of extentarealoss.</em>?????
[ADS-NIPR-JAXA] ASI Extent.
2018 has 220,120 km2 more than 2016 and 90,032 km2 less than 2012 (Which appears for the first time).
An illustration of why for the Central Seas of the CAB especially area is so much better as an indicator of the reality.
I will be posting more on area later today - but wait small, biznis to do first. (Why is retirement so bloody busy?)
- Extent loss for the melting season to date is, at 3.51 million km2, 250k below the average for the last 10 years. That is a significant amount.A whole bin!
Daily NSIDC Extent reveals an UPTICK of +17K. How unusual is this during the months June-July when the melting is at its largest pace?
[quote author3=Lord M Vader link=topic=2223.msg158597#msg158597 date=1528902581]Dispersal could do this, especially considering how fragmented the ice is.
Daily NSIDC Extent reveals an UPTICK of +17K. How unusual is this during the months June-July when the melting is at its largest pace?
Daily NSIDC Extent reveals an UPTICK of +17K. How unusual is this during the months June-July when the melting is at its largest pace?Finally an easy question about arctic sea ice...
Daily NSIDC Extent reveals an UPTICK of +17K. How unusual is this during the months June-July when the melting is at its largest pace?Finally an easy question about arctic sea ice...
According to NSIDC extent data, this happens about 2 times per month in June, and another 1.3 times in July, so nothing to worry about. The typical maximal upward tick is around 40k in June and 25k in July. Even 2012 saw 2 upticks during its spectacular June (but it also saw 13 century breaks).
if dispersion would be the problem, at temps around or above zero, there is no refreeze between fragments, hence area should go down somehow in relation to extent and to me it does not look like it, just show me where i overlook something if that is the case.Gerontocrat posted this chart up-thread showing exactly what you describe, area going down relative to extent. Dispersion.
Over the past nine days, JAXA Arctic extent has dropped by just 286k. That's precisely as much as was lost during the same span in 2015, and 33k more than was lost in 2016. In fact, of the past four seasons (including this one), only 2017 lost more over the span, with a nine-day loss of 696k. (2012 is still the winner for the period by a long shot, dropping a whopping 1.13M km2, or nearly four times as much as this year's loss.)
It will take more time to know for sure, of course, but my guess is that the seeming disappearance of what used to be known as the early June "cliff" is a new (and perhaps temporary) normal, a complex product of lower spring maximums and numerous other factors.
Anyway: JAXA extent is today in 5th place--somewhere it hasn't been since mid-March--and unless it drops by at least 20k tomorrow, 2018 will fall back to 7th place, somewhere it hasn't been this year. 2018 JAXA extent has spent 20 days in 3rd place, 69 days in 2nd, and 66 days in 1st; just nine days have fallen outside the top three.
Over the past nine days, JAXA Arctic extent has dropped by just 286k. That's precisely as much as was lost during the same span in 2015, and 33k more than was lost in 2016. In fact, of the past four seasons (including this one), only 2017 lost more over the span, with a nine-day loss of 696k. (2012 is still the winner for the period by a long shot, dropping a whopping 1.13M km2, or nearly four times as much as this year's loss.)
It will take more time to know for sure, of course, but my guess is that the seeming disappearance of what used to be known as the early June "cliff" is a new (and perhaps temporary) normal, a complex product of lower spring maximums and numerous other factors.
About 230k of the slow decline in the begin of June can be explained by a particular "quirk" in the algorithm that Jaxa is using to calculate sea ice concentration with a "smooth" in the calculation to prevent an ugly bump in extent.
The adapted Bootstrap Algorithm that Jaxa uses switches on the first of June from dry ice surface to melting. The switch back to dry ice is set at 15th October. Some may remember old versions of the Jaxa extent graphs (at the time produced by a cooperation of IARC and Jaxa , known as IJIS), that did show visible "bumps" on these dates. A refinement in the calculation did a way with those, presumably by gradually smoothing the results.
NSIDC ONE DAY DAILY EXTENT DROPPED BY:-
112 k 15th June
110 k 14th June
First double century break of the season? Now the June cliff starts (or not) ?
What glitch ? - Both NSIDC and JAXA extent loss slowed a lot for the week before two days ago, and JAXA extent loss increased a bit on the 14th and rose above average on the 15th.NSIDC ONE DAY DAILY EXTENT DROPPED BY:-
112 k 15th June
110 k 14th June
First double century break of the season? Now the June cliff starts (or not) ?
this is a correction of the recent glitch in sensor reading and/or algorithms IMO
i mean it, not kidding
Independent data sets, different technology and different algorithms.
NSIDC area loss (5 day average) also accelerated on the 14th and 15th.
The data is consistent across all the measures.
What glitch ? - Both NSIDC and JAXA extent loss slowed a lot for the week before two days ago, and JAXA extent loss increased a bit on the 14th and rose above average on the 15th.
Independent data sets, different technology and different algorithms.
NSIDC area loss (5 day average) also accelerated on the 14th and 15th.
The data is consistent across all the measures.
Statements without evidence are not very helpful.
Independent data sets, different technology and different algorithms.
NSIDC area loss (5 day average) also accelerated on the 14th and 15th.
The data is consistent across all the measures.
The weather has been hot for awhile...do we have any clue why the data just picked up in the last couple of days?
if i write IMO it means "in my opinion" and opinions are free and only i know my quota of ultimately having had the feel. perhaps it's poor perhaps it's close to 100% LOL.
a) almost the entire arctic is(was) around or above zero, (hence no refreeze is possible)
b) parts of the ice cover are/was hit with temps way above melting temps and in places above 30C
. (and more widely spread between 20 and 25C)
c) ice is thin and mobile and the winter was warm
d) there have been extraordinarily strong winds recently and rain throwing water on the surface,
. (lowering albedo significantly)
the logics tell us that there has definitely been significant melt in some places but there has
certainly not been any refreeze because temps were far away from freezing point for see-ice.
the result is that there must have been a reduction in ice over all, melt versus no freeeze.
the charts/numbers were showing more or less the same like the day before and the above considered that's not possible without good explanation that evades me.
no, this is not a proof, but it's also not totally of, not enough off to say it's useless to think about it and consider the possibility for errors of the kind WIP mentioned and/or others.
Independent data sets, different technology and different algorithms.
NSIDC area loss (5 day average) also accelerated on the 14th and 15th.
The data is consistent across all the measures.
The weather has been hot for awhile...do we have any clue why the data just picked up in the last couple of days?
that's exactly the question that made me think further and Wipneus posted somewhere a possible explanation.
i believe that the algorithms are based on conditions decades ago when things were easier to calculate, high freeboards, stable ice cover with less fissures where the water can drain instead of ponding etc. etc. who can tell for sure that those calculations have the same accuracy and reliability nowadays like they had 10-15 years ago.
i don't insist that they don't but i suspect that they don't always and simply throw that into the round. gladly listing to proper explanation why my suspicion is wrong. after all i was thinking this is a place to discuss and not one to believe. if we were believers and not seekers for the truth, we could still believe that the earth is a disk. the guy who dared to suspect otherwise has almost been killed and history is full of such examples.
and no, galileo did not have proof in form of an image from space, he just made a logical assumption based on observations. other who did the same were wrong, he was right, so who knows exactly what we shall find out soon what the truth is.
JAXA Extent 10,236,731 km2（June 15, 2018）Thanks, gerontocrat :)
Again,just to add to Juan's post ( I like the table, Juan):
Independent data sets, different technology and different algorithms.
NSIDC area loss (5 day average) also accelerated on the 14th and 15th.
The data is consistent across all the measures.
The weather has been hot for awhile...do we have any clue why the data just picked up in the last couple of days?
that's exactly the question that made me think further and Wipneus posted somewhere a possible explanation.
I believe that the algorithms are based on conditions decades ago when things were easier to calculate, high freeboards, stable ice cover with less fissures where the water can drain instead of ponding etc. etc. who can tell for sure that those calculations have the same accuracy and reliability nowadays like they had 10-15 years ago.
JAXA Extent 110,126,025 km2（June 17, 2018）Wow. :)
I had to check if 11 or 10 was the correct one. I've been doing this for too long 8) 8).JAXA Extent 110,126,025 km2（June 17, 2018）Wow. :)
Magnamentis, thanks for your thoughts. I think it necessary to comment on a couple of your statements in the interests of accuracy. First, sea ice extent is just sea ice extent. There seems to be nothing wrong with the AMSR 2 measurements -- they simply are what they are, and nothing more. Processing the measurements through two different algorithms and getting similar results for extent is pretty persuasive evidence that all is well.
To challenge these measurements just because we think there has been a lot of melting of the ice is rather like challenging an accurate measurement of a person's height just because we think they have lost some weight. One is not directly linked to the other.
Second, Galileo was not persecuted for suggesting the Earth was a sphere and not a disk. He was supporting Copernicus' idea, aided by evidence he, Galileo, had gathered, that the Earth orbited the Sun. This was theologically perilous because it meant the Earth was not the center of the Universe.
BTW, there was ample evidence that the Earth was a sphere by Galileo's time, and it had been gathered and mathematically analyzed. An ancient Greek, Eratosthenes, had made a pretty good calculation of the size of the Earth. And about a hundred years before Galileo was put on trial, Columbus had set sail to the west to get to the East Indies, a journey that would be irrational, if not suicidal, on a flat Earth.
So have I - damn and blastI had to check if 11 or 10 was the correct one. I've been doing this for too long 8) 8).JAXA Extent 110,126,025 km2（June 17, 2018）Wow. :)
JAXA Extent 110,126,025 km2（June 17, 2018)
I think it necessary to comment on a couple of your statements in the interests of accuracy.
JAXA Extent 10,126,025 km2（June 17, 2018)A. You are mixing JAXA extent and NSIDC area.
NSIDC Total Area as at 17th June (5 day trailing average) = 8,723,055 km2
Pardon my ignorance, but why is there such a big difference between the JAXA and NSIDC extents? Do they define the edge of the ice, or minimum concentration to be counted, differently?
Yes. As for the reasons, they might be related to navigational hazards. Of course we here in ASIForum.would like to use most accurate data possible, but we'll have to do with any internally consistent data we get our hands into. If you have info on better sources of data, please make them publicly known. It's common knowledge some instances may withold these off public so release them as soon as is convenient. And the earth is nearly round, just to be sure.NSIDC Total Area as at 17th June (5 day trailing average) = 8,723,055 km2
JAXA Extent 110,126,025 km2（June 17, 2018)
Pardon my ignorance, but why is there such a big difference between the JAXA and NSIDC extents? Do they define the edge of the ice, or minimum concentration to be counted, differently?
JAXA Extent110,126,025km2（June 17, 2018) Error by Gerontocrat - 10,126,025 km2
NSIDC Total Area as at 17th June (5 day trailing average) = 8,723,055 km2
Pardon my ignorance, but why is there such a big difference between the JAXA and NSIDC extents? Do they define the edge of the ice, or minimum concentration to be counted, differently?
JAXA Extent110,126,025km2（June 17, 2018) Error by Gerontocrat - 10,126,025 km2
NSIDC Total Area as at 17th June (5 day trailing average) = 8,723,055 km2
Pardon my ignorance, but why is there such a big difference between the JAXA and NSIDC extents? Do they define the edge of the ice, or minimum concentration to be counted, differently?
Extent is measured by saying if ice cover estimate for each pixel greater than 15% then ice cover = 100%
Area is measured by saying if ice cover estimate for each pixel equals, say, 50%, then ice cover = 50%.
Area estimate is, therefore, always less than extent, whether using NSIDC or JAXA measurements.
My posts use JAXA for extent, NSIDC for area as NSIDC produce area data for each sea daily easily uploaded from NSIDC (https://nsidc.org/arcticseaicenews/sea-ice-tools/). If JAXA produced the same data I would use JAXA data in the interests of consistency.
I try to avoid mixing NSIDC and JAXA extent data as they are always a bit different.
The graph below shows the difference between NSIDC area and NSIDC extent monthly averages for May
Hope that helps.
[ADS-NIPR-JAXA] ASI Extent.I'll point out here, what separates us from 2016 (current #1) is 3-4 days of decent melt, or a week of middling.I'll add that area took a very big hit while extent rose (-140K in fact per Neven).
June 18th, 2018: 10,130,433 km2, a small increase of 4,408 km2. :o
2018 is the seventh lowest on record.
[ADS-NIPR-JAXA] ASI Extent.I'll point out here, what separates us from 2016 (current #1) is 3-4 days of decent melt, or a week of middling.I'll add that area took a very big hit while extent rose (-140K in fact per Neven).
June 18th, 2018: 10,130,433 km2, a small increase of 4,408 km2. :o
2018 is the seventh lowest on record.
While "7th" , things are closer than that number might seem to indicate.
JAXA Extent 10,126,025 km2（June 17, 2018)A. You are mixing JAXA extent and NSIDC area.
NSIDC Total Area as at 17th June (5 day trailing average) = 8,723,055 km2
Pardon my ignorance, but why is there such a big difference between the JAXA and NSIDC extents? Do they define the edge of the ice, or minimum concentration to be counted, differently?
B. The algorithms have different resolutions, so will produce diffetent results for the 15% rule.
C. The data comes from different satellites with different microwave wavelengths and all that stuff.
D. Different coastal masks and other minor issues.
Wipneus can explain in full, but even when you compare extents they will be very different.
A. You are mixing JAXA extent and NSIDC area.
B. The algorithms have different resolutions, so will produce diffetent results for the 15% rule.
C. The data comes from different satellites with different microwave wavelengths and all that stuff.
D. Different coastal masks and other minor issues.
Wipneus can explain in full, but even when you compare extents they will be very different.
That sums it up nicely.
Gridsize is probably the main cause: 25x25km for NSIDC and 10x10km for Jaxa. The instantaneous field of view (IFOV) sizes differ even more: up to 45x73km for NSIDC.
(http://nsidc.org/sites/nsidc.org/files/technical-references/SeaIce_CDR_CATBD_final.pdf).
That means NSIDC will see more extent along the ice edge (the mentioned 15% rule) and that more microwave emissions from land (land spill-over) is contaminating the measurements over water (land is seen as >>100% sea ice concentration).
Both deviation (from the mean values of each month between Jan 79 and May 18) of extent as well as of volume are above the linear trend line from Jan 1979 to May 2018 (last update May 2018 averages). See attached figures.
The idea is of course that the current Arctic Basin is more relevant for September extent and area than more peripheral regions.
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-extent-multiprod.png
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-area-multiprod.png
The latest values on these plots are for May2018, so we can expect both plots to drop further and therefore probably below the mean as further melting occurs in June, July and August, correct?
It is interesting and worrying to note the greater variability in both plots in the past decade or so. Systems often fluctuate more as they move towards threshold conditions.
The latest values on these plots are for May2018, so we can expect both plots to drop further and therefore probably below the mean as further melting occurs in June, July and August, correct?There was a change with the 2007 season towards lower summer/early fall extents without also lower winter extents, causing the yearly rise and fall of extent and volume anomalies. It is moreso a new yearly behavior than a growing instability.
It is interesting and worrying to note the greater variability in both plots in the past decade or so. Systems often fluctuate more as they move towards threshold conditions.
You're comparing Arctic-wide melt with modelled temps from 80N to the North Pole. The relation is tenuous at best, especially now. The Arctic has actually been above average temperature-wise, but a lack of winds is keeping winds static, and only the Siberian side is enduring a solar attack. There was more easy ice to melt during May, especially on the Pacific side.
You're comparing Arctic-wide melt with modelled temps from 80N to the North Pole. The relation is tenuous at best, especially now. The Arctic has actually been above average temperature-wise, but a lack of winds is keeping winds static, and only the Siberian side is enduring a solar attack. There was more easy ice to melt during May, especially on the Pacific side.
True, but most of the ice resides north of the 80th parallel.
Arctic Ocean - Wikipedia
https://en.wikipedia.org/wiki/Arctic_Ocean
The Arctic Ocean occupies a roughly circular basin and covers an area of about 14,056,000 km2 (5,427,000 sq mi), almost the size of Antarctica. The coastline is 45,390 km (28,200 mi) long. It is surrounded by the land masses of Eurasia, North America, Greenland, and by several islands.
You're comparing Arctic-wide melt with modelled temps from 80N to the North Pole. The relation is tenuous at best, especially now. The Arctic has actually been above average temperature-wise, but a lack of winds is keeping winds static, and only the Siberian side is enduring a solar attack. There was more easy ice to melt during May, especially on the Pacific side.
True, but most of the ice resides north of the 80th parallel.
"True, but most of the ice resides north of the 80th parallel."
Nope.
The area of the Arctic Ocean is 14.06 million Km2.
The area of the Arctic above 80 degrees North is 3.875 million km2, just under 28% of the area of the Arctic oceanQuoteArctic Ocean - Wikipedia
https://en.wikipedia.org/wiki/Arctic_Ocean
The Arctic Ocean occupies a roughly circular basin and covers an area of about 14,056,000 km2 (5,427,000 sq mi), almost the size of Antarctica. The coastline is 45,390 km (28,200 mi) long. It is surrounded by the land masses of Eurasia, North America, Greenland, and by several islands.
ps: Apart from the Atlantic side, nearly all melt to date is well below 80+ North (and some not in the Arctic Ocean at all)
Data - such a nuisance
The temperature of the central arctic ocean in summer is pegged to the melting point, as long as ice is still there. Moreover, when the ice is covered with snow, the air is pegged to 0oC, but when the snow is gone and the ice is in partial melt the air is pegged to -1.8oC. So your "cooler summer temps" are nothing but a mirage signalling the deterioration of the arctic.
BTW -- my preferred definition of an ice free Arctic is when the DMI 80N is no longer pegged near 0 in Summer. When there is no longer enough ice to keep it cold then it is effectively ice free.
BTW -- my preferred definition of an ice free Arctic is when the DMI 80N is no longer pegged near 0 in Summer. When there is no longer enough ice to keep it cold then it is effectively ice free.
BTW -- my preferred definition of an ice free Arctic is when the DMI 80N is no longer pegged near 0 in Summer. When there is no longer enough ice to keep it cold then it is effectively ice free.
I've often thought about this moment because it would be so seminal, but never viewed it from the ice-free perspective. I hope I'll remember this quote when it happens and write about it. If I don't, remind me. :)
The temperature of the central arctic ocean in summer is pegged to the melting point, as long as ice is still there. Moreover, when the ice is covered with snow, the air is pegged to 0oC, but when the snow is gone and the ice is in partial melt the air is pegged to -1.8oC. So your "cooler summer temps" are nothing but a mirage signalling the deterioration of the arctic.
I continue to believe that (virtually) only the CAB matters when it comes to determining if the September SIE is a record or not. I certainly understand that lingering 'regional' sea ice extent will delay CAB ice loss in the region borders. But when I see CAB extent setting a current date minimum, I do not discount the possibility of a new minimum.
That SIA is only near the current date minimum puts a small damper on this 'pessimistic view' of ice survival. The two graphs suggest that CAB ice compaction is higher now than in other years, and that is sure to put a damper on future internal CAB melt.
The temperature of the central arctic ocean in summer is pegged to the melting point, as long as ice is still there. Moreover, when the ice is covered with snow, the air is pegged to 0oC, but when the snow is gone and the ice is in partial melt the air is pegged to -1.8oC. So your "cooler summer temps" are nothing but a mirage signalling the deterioration of the arctic.
BTW -- my preferred definition of an ice free Arctic is when the DMI 80N is no longer pegged near 0 in Summer. When there is no longer enough ice to keep it cold then it is effectively ice free.
<snippage>I agree - the peripheral seas are secondary to what's happening in the basin proper, which will have the greatest immediate impact on seasonal weather.
That SIA is only near the current date minimum puts a small damper on this 'pessimistic view' of ice survival. The two graphs suggest that CAB ice compaction is higher now than in other years, and that is sure to put a damper on future internal CAB melt.
DMSP F18 to undergo testing late June, early July
June 22, 2018
The Defense Meteorological Satellite Program (DMSP) F18 satellite will be undergoing testing from June 25 to 29 and from July 9 to 12. During this time, data from the Special Sensor Microwave Imager/Sounder (SSMIS) sensor on F18 may have degraded quality or may not be collected. DMSP F18 is the primary sensor that provides NSIDC with near-real-time data for sea ice monitoring (nsidc-0081, the Sea Ice Index, and the Arctic Sea Ice News and Analysis web page). If the data quality does not meet operational standards, NSIDC will remove the resulting sea ice fields or NSIDC may not distribute data from the F18 SSMIS during the test periods.
Sorry guys. No ADS this weekend… :P
Our service will be stopped from June 22 to 25 by planed electrical outage for legal inspection.
8:41 PM - 22 Jun 2018
Now ADS service is down due to system failure from 25th June.
6:54 PM - 25 Jun 2018
NSIDC DATA - Nearing the end?
https://www.theguardian.com/science/2017/nov/05/donald-trump-accused-blocking-satellite-climate-change-research
It seems that NASA have decided that DMSP satellite F-19 cannot be made operational, and has been abandoned.
DMSP satellite F-20 was destroyed by order of Congress.
The current satellites are already working beyond their shelf-life and the earliest replacement date is 2023.
It is highly likely that NSIDC data will be interrupted temporarily or permanently.
“This is like throwing away the medical records of a sick patient,” said David Gallaher of the National Snow and Ice Data Center in Boulder, Colorado. “Our world is ailing and we have apparently decided to undermine, quite deliberately, the effectiveness of the records on which its recovery might be based. It is criminal.”
However, this criminal act lies not with Trump but at the door of Rep. US Senator Lamar Smith, current chairman of the U.S. House Science, Space and Technology Committee.
He is not standing for re-election next year, and the hurrahs vs eulogies have already started.
http://beta.latimes.com/business/hiltzik/la-fi-hiltzik-lamar-smith-20171103-story.html
https://www.texastribune.org/2017/11/02/lamar-smith-retiring-congress/
Ah, but NSIDC area dropped -256k.
Indeed, and if extent by contrast goes up by 55K, compactness drops by a massive 3 percentage points. May I point out that his melting season is a bit crazy?
This is 545k above the 2010-2017 average (and only 129k below the 2000's average on this date).[/b]
That's a lot of ice. 545k km2 of ice even at an average thickness of 1/2 a metre is 270+ gigatonnes, nearly the average annual volume loss according to PIOMAS.
NSIDC Total Area as at 26 June (5 day trailing average) = 8,252,513 km2The average loss from PIOMAS over the past 40 years is 16,900 km^3. 545K km^2 of area half a meter thick is only 272 km^3 and represents only 1.6% of the average loss.
This is 545k above the 2010-2017 average (and only 129k below the 2000's average on this date).
That's a lot of ice. 545k km2 of ice even at an average thickness of 1/2 a metre is 270+ gigatonnes, nearly the average annual volume loss according to PIOMAS.
NSIDC Total Area as at 26 June (5 day trailing average) = 8,252,513 km2The average loss from PIOMAS over the past 40 years is 16,900 km^3. 545K km^2 of area half a meter thick is only 272 km^3 and represents only 1.6% of the average loss.
This is 545k above the 2010-2017 average (and only 129k below the 2000's average on this date).
That's a lot of ice. 545k km2 of ice even at an average thickness of 1/2 a metre is 270+ gigatonnes, nearly the average annual volume loss according to PIOMAS.
or we have a real cliff ;)
This is the first time I remember seeing such a strange result, does it happen often?
Oh, I forgot to mention this:
https://forum.arctic-sea-ice.net/index.php/topic,2223.msg160176.html#msg160176
which, I think, is the real reason.
Thanks Ned. I do think a better aporoximation would be by taking UH AMSR2 numbers whch I suspect would have lower results, but I am away from my PC and cannot do the analysis.I have zero time to be doing this, but you have provoked me into doing it anyway ;)
| Date | Jaxa(Avg) | Jaxa(NSIDC) | Jaxa(Bremen) |
| 22 June | 9.92 | 9.95 | 9.94 |
| 23 June | 9.85 | 9.87 | 9.87 |
| 24 June | 9.76 | 9.84 | 9.82 |
| 25 June | 9.69 | 9.80 | 9.81 |
| 26 June | 9.61 | 9.82 | 9.73 |
| 27 June | 9.53 | n/a | 9.64 |
The current NSIDC values are in all likeliness wrong , drop in area -750k. See also the delta map for the mess.We did have something like a week of compaction, wind,waves and low levels moisture blowing into that area, followed by the reverse for the last few days. Is it possible that it may have expanded into the threshold where gaps between floes cross the threshold where they are noticed by the sensors? SMOS seem to be showing a similar thing. And where I find a few rare gaps in the cloud and fog there it seems to be a field of floes dispersed in open water. It could be errors on both sides of the temporal range?
I expect a correction or withdrawal of the data.
The current NSIDC values are in all likeliness wrong , drop in area -750k. See also the delta map for the mess.
I expect a correction or withdrawal of the data.
Of course it's wrong. I just thought it was funny to show what the effect on compactness was, especially given that it dropped to almost lowest on record (difference 0.1%). That's why I labelled the graph 'NSIDC data error'. Has it been seized upon by climate risk deniers yet to show how we alarmists have gone nuts? ;)Perhaps its been wrong for the past two weeks and now we are getting the correction ;)
My patience with JAXA wears thin ...For now I've switched to looking at Uni Bremen's AMSR2 extent. It's not a perfect analogue for JAXA. During the winter UB extent is about 600k greater than JAXA, and during the summer that difference drops to around 200k. So during June it tends to show larger daily decreases than JAXA does, in order to make up most of that 400k difference.
Fed up waiting on JAXA too
I reckon Ill look again when it is 4.5m on September 9th 2018
Fed up waiting on JAXA too
I reckon Ill look again when it is 4.5m on September 9th 2018
and felt it happens always when things are most interesting, this could be a subjective impression but still, unfortunately didn't write down the dates but always when key events unfold or final seasonal results are approaching we are without data.
Scientists all over the world rely on the sea-ice record compiled by the US National Snow and Ice Data Center (NSIDC) in Boulder, Colorado. But the US military satellites that collect the data, by measuring ice extent using microwave sensors, are approaching the end of their lives. Three are still working but ageing, and their intended successor started experiencing glitches in 2016, before conking out for good this month. The next possible replacement won't launch until at least the early 2020s.
That means the most complete and most scientifically significant sea-ice record is at risk of breaking. Any gap in satellite coverage is not just a short-term problem: it would compromise future research, because scientists would not be able to accurately compare observations made before the gap with those from afterward.....
Centre analysts have begun testing the inclusion of sea-ice data from a Japanese satellite, but that spacecraft—designed to last five years—is now five years old. Experts looking to avert the looming gap will gather to debate other options, including the potential use of data from a Chinese satellite, in December, at a meeting of the American Geophysical Union in New Orleans, Louisiana.
Below is why I get the shivers every time the satellites go into testing mode.
Things not any better since the article was published last year?
Note the reference to JAXA below
https://www.scientificamerican.com/article/ageing-satellites-put-crucial-sea-ice-climate-record-at-risk/
Republicans in the U.S. congress ordered the already built follow on satellite destroyed to intentionally blind us in the Arctic and berated the U.S. military for building and storing the satellite.
In general, Congresses and White House staff of both parties have really had trouble understanding ...Should have noted that Al Gore was a notable exception to this rule. In the alternate universe where Gore became President in 2001, the USA in 2018 has a much stronger and better developed earth observation satellite program.
Compactness is quite high at the moment:
(https://i.imgur.com/quR2HDq.png)
(https://i.imgur.com/OUrDRhQ.png)
Where do you find this information? I made a few observations and guesses a month ago based on the DMI modeled ice thickness that melting would be slow. Compactness as shown on DMI map suggested melting around the edges, followed by a slowdown.
I wonder where that Bering ice is as both NOAA as well as climate reanalyzer show water temperatures above +4-+6°C and SST anomalies between +3 and more than +6°C. Is that really ice what they detect? The same is almost true for the Okhtsk Sea (maybe just in the SW-most corner some ice could have survived...)Click on the attached image and wander around the fringes.
Area graphs as at 30 June -derived from NSIDC Regional Sea Data 5 Day Trailing AverageCan you do Hudson Bay and Okhotsk please ;D
Graphs 5 to 7 attached below.
Area graphs as at 30 June -derived from NSIDC Regional Sea Data 5 Day Trailing AverageCan you do Hudson Bay and Okhotsk please ;D
Graphs 5 to 7 attached below.
I know Okhotsk is all gone but curious to see how early vs. other decades.
Interesting, ice extent in 2018 is barely lower than 2001 and 2005 on 30-06-18.
Interesting, ice extent in 2018 is barely lower than 2001 and 2005 on 30-06-18.Which says more about the limitations of extent as a meaningful gauge of overall ice condition going into summer than it does about this year vs others. Consider where the ice is, condition, and likely weather ahead -- I wouldn't make too much of daily numbers, especially extent.
Another way of looking at this is that both 2001 and 2005 were record lows for June 30th and 2018 is a few hundred thousand km^2 below both of them on this date despite having a much bigger extent than 6 of the past 10 years.Interesting, ice extent in 2018 is barely lower than 2001 and 2005 on 30-06-18.Which says more about the limitations of extent as a meaningful gauge of overall ice condition going into summer than it does about this year vs others. Consider where the ice is, condition, and likely weather ahead -- I wouldn't make too much of daily numbers, especially extent.
| Date | Jaxa(actual!) | Jaxa(Avg) | Jaxa(NSIDC) | Jaxa(Bremen) |
| 22 June | 9.90 | 9.92 | 9.95 | 9.94 |
| 23 June | 9.84 | 9.85 | 9.87 | 9.87 |
| 24 June | 9.77 | 9.76 | 9.84 | 9.82 |
| 25 June | 9.70 | 9.69 | 9.80 | 9.81 |
| 26 June | 9.63 | 9.61 | 9.82 | 9.73 |
| 27 June | 9.56 | 9.53 | n/a | 9.64 |
Thanks Ned. I do think a better aporoximation would be by taking UH AMSR2 numbers whch I suspect would have lower results, but I am away from my PC and cannot do the analysis.I have zero time to be doing this, but you have provoked me into doing it anyway ;)
Date Jaxa(Avg) Jaxa(NSIDC) Jaxa(Bremen) 22 June 9.92 9.95 9.94 23 June 9.85 9.87 9.87 24 June 9.76 9.84 9.82 25 June 9.69 9.80 9.81 26 June 9.61 9.82 9.73 27 June 9.53 n/a 9.64
All three columns of data are predictions for the missing days of JAXA extent:
First = based on last reported value and average rate of decline on this date (2007-2017)
Second = based on last reported value and NSIDC
Third = based on last reported value and Uni Bremen
.......attempts to "predict" the missing JAXA values based on either NSIDC or Uni Bremen.
Turns out that they were both biased slightly too high. Ignoring the other extent metrics and just taking the average decline (2007-2017) for each day would have been slightly too low, but better.
This is somewhat galling. Incorporating knowledge of extent from NSIDC and Bremen made the predictions worse? I guess the "problem" is just that 2018 was too close to the average during this six-day period to leave room for much improvement.
Richard Rathbone
Century increase in NSIDC tomorrow? (as the faulty data of 27th drops out of the 5 day average)
The June 3rd decrease of 53k
I expect July melt to catch up some of the ground (un)lost in June, including some century breaks, due to losses in the periphery.
Watching ice like that, typically at this stage it's about 7-10 days from disappearing.I expect July melt to catch up some of the ground (un)lost in June, including some century breaks, due to losses in the periphery.
In support of that, the South Kara Sea ice (below, unaltered image) is looking particularly dark and gray these days, and the Hudson ice seems a similar shade. So albedo is getting lower, and both are currently receiving a good deal of insolation.
It has passed 30+ minutes of the usual time and ADS NIPR has no data.Glad to oblige, Juan.
So, I appreciate if someone else post the data, at least extent and daily drop.
Thanks!
It has passed 30+ minutes of the usual time and ADS NIPR has no data.Glad to oblige, Juan.
So, I appreciate if someone else post the data, at least extent and daily drop.
Thanks!
The big question for me is: "Will Hudson Bay and Kara sea completely melt out?"
Ditto to this. The Kara and Hudson have melted out completely or almost completely for the last 15 years. But I realize it is perfectly possible that you were being ironical. If so, I have felt the burn on this issue, and I have been converted (with much reluctance) to emoticons. May I recommend :o or ;D or 8) ....The big question for me is: "Will Hudson Bay and Kara sea completely melt out?"
No reason to suppose Hudson Bay will not melt out completely. Already well over half gone.
Kara Sea will probably almost completely melt out as usual. Also well over half gone.
They are just a bit late this year.
The atlantc side is skewing the inner basin drops.
The Pacific side has been well protected.
So a slow down is very likely as we go along
2018 has also seen the longest May/June/July stretch on record with no century decreases. The last century break was on May 5, and, in fact, there have only been two so far this year. By way of comparison, the 10-year average by this date has been 19, with 2012 seeing 40 by now.
| 2003 | 3 |
| 2004 | 7 |
| 2005 | 4 |
| 2006 | 8 |
| 2007 | 11 |
| 2008 | 4 |
| 2009 | 9 |
| 2010 | 9 |
| 2011 | 8 |
| 2012 | 23 |
| 2013 | 13 |
| 2014 | 13 |
| 2015 | 7 |
| 2016 | 5 |
| 2017 | 6 |
| 2018 | 2 |
Looking ahead ... as Stephan says, it seems unlikely that the ssslllooowww extent decreases will continue. Something's gotta change there. I'm surprised it's lasted this long, actually. Not many years have such a radical change in compactness during the melt season.
As long as area keeps dropping fast , and extent doesn't respond, compactness will drop fast too. Right now it's lowest in the 2005-2018 record:I've been watching the divergence in behavior between area and extent with considerable interest.
Here's the chart version of the table I posted earlier -- number of JAXA extent century breaks so far this year, compared to the same period in previous years:
(https://i.imgur.com/sIHCKjm.png)
I've been watching the divergence in behavior between area and extent with considerable interest.
I think it speaks to the fundamental changes in the structure of the pack. I'm hesitant to make any specific conclusions about it yet, but anecdotally it appears we are seeing more smaller floes being dispersed over a larger area, and a lot more melting inside the core extent of the pack than we've typically seen in the past. That there may be the key distinction between 2018 and previous melt seasons.
[Edit:] A pack with smaller more mobile floes would also help explain the wide variation in and rapid changes to compactness.
As long as area keeps dropping fast , and extent doesn't respond, compactness will drop fast too. Right now it's lowest in the 2005-2018 record:
Edited to add: Jim, is it possible that you're comparing 2018's year-to-date value (for number of century breaks) to previous years' 365-day totals, rather than year-to-date?
Perhaps JAXA extent losses will, over the next few days, catch up a bit with the greater than average area losses recorded by NSIDC over the last few days.
Gerontocrat (or somebody else who knows the answer :D), I have to ask does Jaxa provide/calculate new "numbers" or "stats" (Idk how should I call it) every day, or is it 2-day average?2 day.
Posted by: Jim Pettit
Today at 02:13:03 PM
NSIDC ASI extent increased for a second day, dropping that metric back even further, to 12th place. July daily increases aren't unheard of, but they are fairly rare; since 2010, there have only been 12 of them, with two of those over the past two days. And in fact, yesterday's increase of 71k was the single largest one-day July increase since at least 2000.
At this moment, it seems likely (though no way guaranteed) that 2018 NSIDC extent will end up at or above 5M km2. Even a finish identical to 2012's monstrous August drop would render a rather quotidian 4.38M km2.