Arctic Sea Ice Extent, Area, and Volume

[ORH_wxman]

Wipneus has finally started giving some NSIDC updates again, so we can compare to past years on CT SIA....the following shows where other year's are in relation to this year (i.e., 2016 was 240k lower than this year on this date)

2016: -240k

2015: +200k

2014: +240k

2013: +520k

2012: -590k

2011: +10k

2010: -620k

2009: +780k

2008: +150k

2007: -130k

 

You can see the closest match right now is 2011, though 2011 saw nuclear drops in the final 4 days of June, so it will be tough to keep up with that year for June 30th readings (which aren't available until July 1st). Traditionally, I have used the end of June's value to predict the final outcome of CT SIA with moderate success...though last year was a huge miss outside of the 5% confidence intervals. It was the largest loss of area after June 30th in the data base including 2012. So we'll see how well it does this year.

As a reminder, here are the minimums on CT SIA (or the NSDIC equivalent) each year since 2007:

 

2007: 2.919

2008: 3.003

2009: 3.424

2010: 3.072

2011: 2.904

2012: 2.234

2013: 3.554

2014: 3.483

2015: 3.094

2016: 2.427

 

 

You can actually see how using past years to predict what 2016 would be all fell outside of what actually happened....the graph below shows what 2016 "would have" finished with if it followed that year...I plotted the actual result of 2016 on the end to show how it was lower than previous variations of area loss after June 30th. The closest result would have been following the losses after June 30th in 1989...but that still would have produced a value of 2.53 million sq km. Previously, there had been no trend in area loss after June 30th, which made the prediction somewhat reliable. But we'll have to see if 2016 is the start of a downward trend or if it was an outlier.

 

 

[skierinvermont]

When you include 2016, the years after 2007 look to have a slightly bigger area drop after June 30th than the years before 2007. Not sure if it's significant though.

[ORH_wxman]

12 minutes ago, skierinvermont said:

When you include 2016, the years after 2007 look to have a slightly bigger area drop after June 30th than the years before 2007. Not sure if it's significant though.

Agreed...the last two years especially make the more recent trend more noticeable. The 2010-2014 (sans 2012) stretch was kind of middle of the pack but we've seen pretty good losses the past couple years and when you start adding in 2012, 2008, and 2009, it might be a newer normal. We'll have to see, but it's becoming harder to envision losses that are closer to 3.5 million sq km after June 30th versus 4 million sq km in the post 2007 years (average since 2007 has been 4.1 million sq km versus 3.56 from 1996-2006 or 3.73 if we include 1979-2006)

 

I'll probably adjust my forecast this year to assume losses closer to the 2007-2016 average post-June 30th.

[ORH_wxman]

FWIW, the outliers for post June 30th losses since 2007 are 3.70 million sq km in 2010 and 4.51 million sq km in 2016. That's still a pretty wide range that has to be taken into account in the uncertainty.

[ORH_wxman]

With a couple days left before the June 30th prediction point, here's where we stand on area:

 

2016: -330k

2015: +30k

2014: +110k

2013: +280k

2012: -700k

2011: -320k

2010: -650k

2009: +640k

2008: +130k

2007: -160k

 

 

[WinterWxLuvr]

6 hours ago, ORH_wxman said:

With a couple days left before the June 30th prediction point, here's where we stand on area:

 

2016: -330k

2015: +30k

2014: +110k

2013: +280k

2012: -700k

2011: -320k

2010: -650k

2009: +640k

2008: +130k

2007: -160k

 

 

Does this mean 2017 is less than 2016 by 330k or vice versa?

[ORH_wxman]

53 minutes ago, WinterWxLuvr said:

Does this mean 2017 is less than 2016 by 330k or vice versa?

It means 2016 was 330k lower than 2017...you can kind of tell just looking at the years. All the negative years are the bad ones like 2007, 2010, 2012, 2016....and the ones positive or higher than this year are the better ice retention years like 2014, 2013, 2009, etc.

 

This year has kind of an in-between vibe to me...like a 2008 or maybe 2015 (talking area...because 2015 was low extent, but very compacted so the area actually wasn't that low in the post-2007 context).

[WidreMann]

I still don't see how we don't beat 2012. The pattern doesn't look great for the foreseeable future and the ice is in terrible shape. Extent may be better than 2012, but thickness is downright awful. I could see us falling off a cliff in July.

[The_Global_Warmer]

Ł

 

 

Looks like the wrather is really pushing  towards a top 3 finish    

 

 

So much warm open water coupled with:

 

relentless sun.

Land driven warmth.

Favorable  winds to drive compaction.

 

So some excitement.

[bluewave]

JAXA looks like it's on target to finish very close to last year if there is an average 2007-2016 melt rate for the rest of the summer.

 

 

 

 

 

[ORH_wxman]

9 hours ago, WidreMann said:

I still don't see how we don't beat 2012. The pattern doesn't look great for the foreseeable future and the ice is in terrible shape. Extent may be better than 2012, but thickness is downright awful. I could see us falling off a cliff in July.

2012 likely already has lower volume now than 2017 (they were basically tied in the mid-month PIOMAS update) and the area at this point as measured by NSIDC SSMI/S (CT SIA by proxy) was significantly lower in 2012 which suggested a lot more melt ponding than this year. We will need a pretty incredible weather pattern to finish lower than 2012 IMHO. It's not impossible, but I'd put the chances as very unlikely.

[ORH_wxman]

Final June area numbers are in and my prediction will probably be somewhere around 3.1 million sqkm for area. I'll have the full expected distribution of results in the next day or two when I have time to run them on excel. We finished the month 250k higher than last year...so that is probably going to put the chances at beating 2012 near zero considering even last year's epic melt out post-June didn't break it. 

 

[chubbs]

The SIPN June predictions have a median forecast a little below last year but well above 2012. Forecasts are for the average monthly extent in September with 2012 at 3.6 M.

https://www.arcus.org/sipn/sea-ice-outlook/2017/june

[stadiumwave]

On 6/26/2017 at 2:29 PM, forkyfork said:

it says a lot about the state of the ice that mundane melt weather could still bring a top 5 low finish

 

Actually...to me it's pretty remarkable we don't beat 2012 considering where we started.

[ORH_wxman]

Here's the distributions of the final area minimum should 2017 follow the same path of each previous year's melt after June 30th. (I.E. you can see that if we followed 2015's melt after June 30th, our minimum would be at 3.00 million sq km)

 

Using percentiles, the 10th percentile is 2.87 million sq km and the 90th is 3.87 million sq km with a median of 3.31 million sq km...however, that is using the entire distribution since 1979 and as I noted in a discussion with skierinvermont, the recent years may be starting to trend a little higher for ice loss after June 30th...this isn't conclusive yet, but I think it should be mentioned. If we only use 2007-2016, then our percentiles would change...you'd get a 10th percentile of 2.80, a 90th perecentile of 3.31 and a median of 3.12. Note how the 90th percentile for post-2007 is the same as the median for the entire distribution...this is because in the past 10 years, we haven't had any of those very slow post-June 30th melt years like we saw especially in the 1990s....but even 2005 and 2006 were quite slow in area loss after June 30th.

 

Thus, given all the information...my prediction for 2017 min will be 3.10 plus or minus 200,000 sq km...so a range of 2.90 to 3.30. This covers a lot of rankings of course. We could theoretically finish anywhere from #3 to #8.

[csnavywx]

PIOMAS actually stayed slightly below 2012 -- or a statistical tie, so it definitely hasn't lost much ground over the past 2 weeks. Most of the gap closing occurred early in the month.  Current anomaly is the lowest on record. As far as the state of the pack is concerned -- it's definitely weaker on the Pacific and ESS-Laptev front and definitely stronger on the Atlantic/Kara side.

The dipole shuts down after D5 (as far as the OP runs are concerned) and a cool PV pattern is dominant on the ensembles. This year has waffled rapidly back and forth, so we'll see if that continues.

[bluewave]

21 hours ago, csnavywx said:

PIOMAS actually stayed slightly below 2012 -- or a statistical tie, so it definitely hasn't lost much ground over the past 2 weeks. Most of the gap closing occurred early in the month.  Current anomaly is the lowest on record. As far as the state of the pack is concerned -- it's definitely weaker on the Pacific and ESS-Laptev front and definitely stronger on the Atlantic/Kara side.

The dipole shuts down after D5 (as far as the OP runs are concerned) and a cool PV pattern is dominant on the ensembles. This year has waffled rapidly back and forth, so we'll see if that continues.

It's interesting how big a difference the extents can vary with similar volume depending on weather conditions. We saw the divergence between 11 and 12 extents on similar volume due to the much more hostile weather pattern in 12.

 

 

 

[ORH_wxman]

3 minutes ago, bluewave said:

It's interesting how big a difference the extents can vary with similar volume depending on weather conditions. We saw the divergence between 11 and 12 extents on similar volume due to the much more hostile weather pattern in 12.

 

 

2012 and 2011 were fairly different in volume by September though, 2012 was clearly lower...they were close in July. A much better example IMHO would be 2007...it had a much higher September volume than years like 2013 and barely lower than 2009...yet it had one of the lowest extents/areas at the minimum due to the extreme compaction (caused by the weather)....way lower than 2009/2013.

[bluewave]

15 minutes ago, ORH_wxman said:

2012 and 2011 were fairly different in volume by September though, 2012 was clearly lower...they were close in July. A much better example IMHO would be 2007...it had a much higher September volume than years like 2013 and barely lower than 2009...yet it had one of the lowest extents/areas at the minimum due to the extreme compaction (caused by the weather)....way lower than 2009/2013.

You are right. That was probably the better example of Volume vs extent divergence. 2007 was the year of the mega dipole. Remarkable how a version of the summer pattern repeated much of the time until 2012 and then abruptly reversed.

[ORH_wxman]

10 minutes ago, bluewave said:

You are right. That was probably the better example of Volume vs extent divergence. 2007 was the year of the mega dipole. Remarkable how a version of the summer pattern repeated much of the time until 2012 and then abruptly reversed.

Also, probably one of the more underrated events during the whole decline of sea ice in the past decade-plus is the winter of 2007-2008. 2007 might not have been a complete game-changer had the 2007-2008 winter not exported a ton of that compacted multiyear ice. While the summer of '07 melted out a lot of volume, even more was exported the following winter...the '07 summer pushed/compacted all the MYI leftover from the 2006 season (and previous seasons) toward Greenland/CAA and then a really hostile winter/spring pattern proceeded to export a lot of that ice...expediting the transition from a lot of MYI to mostly FYI.

[chubbs]

PIOMAS is out for June. As expected volume loss was slower in May and June than 2012 and other recent big melt years, but 2017 has retained the lowest PIOMAS volume, not far from 2012 in the last week of June.

[bluewave]

17 hours ago, ORH_wxman said:

Also, probably one of the more underrated events during the whole decline of sea ice in the past decade-plus is the winter of 2007-2008. 2007 might not have been a complete game-changer had the 2007-2008 winter not exported a ton of that compacted multiyear ice. While the summer of '07 melted out a lot of volume, even more was exported the following winter...the '07 summer pushed/compacted all the MYI leftover from the 2006 season (and previous seasons) toward Greenland/CAA and then a really hostile winter/spring pattern proceeded to export a lot of that ice...expediting the transition from a lot of MYI to mostly FYI.

June officially continues the post 2012 pattern of a more active polar vortex and cooler temps.You can see the long range ensembles continuing this general pattern right into July.

 

 

 

 

 

[chubbs]

48 minutes ago, bluewave said:

June officially continues the post 2012 pattern of a more active polar vortex and cooler temps.You can see the long range ensembles continuing this general pattern right into July.

 

 

 

 

Interesting charts. Highlights the difficulty in predicting sea ice, particularly a record low, with any lead time. Note though that the trend in 925 mb temps is upward so the dice are slowly being loaded.

[bluewave]

26 minutes ago, chubbs said:

Interesting charts. Highlights the difficulty in predicting sea ice, particularly a record low, with any lead time. Note though that the trend in 925 mb temps is upward so the dice are slowly being loaded.

While the overall annual temperature  trend is an unmistakable up, it would be interesting to know what changed after the 2012 summer. To get a 6 year historic stretch of dipole patterns during the summer and then a reversal is pretty extreme 500 mb behavior.

 

 

[chubbs]

1 hour ago, bluewave said:

While the overall annual temperature  trend is an unmistakable up, it would be interesting to know what changed after the 2012 summer. To get a 6 year historic stretch of dipole patterns during the summer and then a reversal is pretty extreme 500 mb behavior.

 

Hopefully not the sun.

[bluewave]

44 minutes ago, chubbs said:

Hopefully not the sun.

It's funny how the pattern reversed right after the paper was published.

http://onlinelibrary.wiley.com/store/10.1029/2012GL053268/asset/grl29604.pdf;jsessionid=F7950891CB18B3DB5580C02EC912A4A1.f01t03?v=1&t=j4ppf2qo&s=29436c163ab48e25e8f4989445de41091a8d6ccd&systemMessage=Wiley+Online+Library+'Journal+Subscribe+%2F+Renew'+page+will+be+down+on+Wednesday+05th+July+starting+at+08.00+EDT+%2F+13.00+BST+%2F+17.30+IST+for+up+to+75+minutes+due+to+essential+maintenance.

Thus we can say that a six year run of near one standard deviation negative excursions (2007–2012) is unique in the 63 year record. To further test the significance of the 2007–2012 AD patterns we randomly generated 10,000 time series, each with 63 points to match the observed time series and with a normal distribution without autocorrelation. For this simple calculation, the chance for having five consecutive values with a negative AD of magnitude greater than 1.0 standard deviation units in a sample size of 63 is rare, less than 1 in a 1000.

[so_whats_happening]

7 hours ago, chubbs said:

PIOMAS is out for June. As expected volume loss was slower in May and June than 2012 and other recent big melt years, but 2017 has retained the lowest PIOMAS volume, not far from 2012 in the last week of June.

curious what causes the low around the beginning of july to not continue does it have to do with at this point most of the outer regions have melted out and you just have the core which usually maintains?

[WidreMann]

44 minutes ago, so_whats_happening said:

curious what causes the low around the beginning of july to not continue does it have to do with at this point most of the outer regions have melted out and you just have the core which usually maintains?

It is an anomaly chart, so what you are really asking is why doesn't the anomaly just get worse and worse. My guess would be that the sun angle starts to lower at the end of June and southerly parts of the arctic begin to have night, so heating effects lessen as the summer goes on. That means there's a sort of upper limit to how much warming will happen.

[chubbs]

35 minutes ago, so_whats_happening said:

curious what causes the low around the beginning of july to not continue does it have to do with at this point most of the outer regions have melted out and you just have the core which usually maintains?

That is my guess - there is less volume to lose late in the melt year. On a percentage basis, the volume anomaly is largest at the September low.

[so_whats_happening]

5 minutes ago, WidreMann said:

It is an anomaly chart, so what you are really asking is why doesn't the anomaly just get worse and worse. My guess would be that the sun angle starts to lower at the end of June and southerly parts of the arctic begin to have night, so heating effects lessen as the summer goes on. That means there's a sort of upper limit to how much warming will happen.

Basically the apex of summer heating up there is currently happening. Makes sense also have noticed that the Atlantic side of the arctic has been experiencing rather cool surface waters as of late is this due to the melting process that occurs or is it something else that could be causing this because on the Pacific side near chuchki(SP?)  sea there are have been persistent anomalous warm waters for quite a while.