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ORH_wxman

Arctic Sea Ice Extent, Area, and Volume

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2 hours ago, forkyfork said:

the loss of CT data really puts a damper on tracking 

NSIDC (CT SIA's source) is still transmitting SSMI/S and wipneus posts it...but it is really annoying that we don't have it on the CT SIA graph and also their spreadsheet which made it easy to look up. 

But area right now sits at 4.03 million sq km. That would be 7th place...barely under 2010 .

Other years:

2016: 3.70

2015: 3.79

2014: 4.55

2013: 4.31

2012: 3.09

2011: 3.56

2010: 4.06

2009: 4.33

2008: 3.89

2007: 3.68

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10 minutes ago, WidreMann said:

What's the CT data?

Cryosphere Today...it was a webpage from U Illinois that tracked sea ice area from the SSMI/S satellite. NSIDC uses the same one but they don't really show much data on area...all their graphs are extent. CT put the area in graphical format and also in tabular format. But it stopped transmitting data sometime in early 2016...at first they said they were going to be back soon but then the site went dark and it never updated. 

Area is nice to use because it tends to be a better predictor of extent 30-60 days out than extent itself is...but not having CT's easy-to-read data is really annoying. 

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So far it looks like the Arctic storm has slightly slowed the decline rate as the pack appears to be spreading out a bit. The storm has brought an early freeze for the post 2005 Arctic. Right now the extent is tracking between 2007 and 2016 as 2012 pulls further out of reach. 

 

598c464704e51_Screenshot2017-08-10at7_35_25AM.png.5bf5c44ba6c87a7f7b4f121d7ca71d84.png

meanT_2017.png.43f5ed2414810d6bf636f6d219c2113a.png

 

 

 

 

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This year's low volume/high NSIDC area status is unusual. Looks like the mild winter is having some impact but is a weaker factor than a slow start to the Arctic Ocean melt season.

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1 hour ago, chubbs said:

This year's low volume/high NSIDC area status is unusual. Looks like the mild winter is having some impact but is a weaker factor than a slow start to the Arctic Ocean melt season.

There may also be a higher degree of uncertainty in the PIOMAS data compared to other years. But we saw how the the PIOMAS and NSIDC extent widely diverged in 2013 compared to the 2007 season. Lower PIOMAS in 2013 vs 2007,but the cool 2013 summer resulted in a much higher higher September extent than 2007.

http://nsidc.org/arcticseaicenews/2017/03/

It was a very warm autumn and winter. Air temperatures at the 925 hPa level (about 2,500 feet above sea level) over the five months spanning October 2016 through February 2017 were more than 2.5 degrees Celsius (4.5 degrees Fahrenheit) above average over the entire Arctic Ocean, and greater than 5 degrees Celsius (9 degrees Fahrenheit) above average over large parts of the northern Chukchi and Barents Seas. These overall warm conditions were punctuated by a series of extreme heat waves over the Arctic Ocean.

Data from the European Space Agency’s CryoSat-2 satellite indicate that this winter’s ice cover may be only slightly thinner than that observed at this time of year for the past four years. However, an ice-ocean model at the University of Washington (PIOMAS) that incorporates observed weather conditions suggests the volume of ice in the Arctic is unusually low.

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7 hours ago, bluewave said:

So far it looks like the Arctic storm has slightly slowed the decline rate as the pack appears to be spreading out a bit. 

 

Quite the Contrary.

FYJ0pLI.png

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Yeah it's actually a pretty compact ice pack right now. I think the cyclone perhaps has just slowed the peripheral melting. 

Though bluewave is correct that typically cyclones over the CAB try and disperse the ice. But the concentration hasn't suffered even if it is doing that. 

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1 hour ago, ORH_wxman said:

Yeah it's actually a pretty compact ice pack right now. I think the cyclone perhaps has just slowed the peripheral melting. 

Though bluewave is correct that typically cyclones over the CAB try and disperse the ice. But the concentration hasn't suffered even if it is doing that. 

Yeah, the record August 2012 storm seemed to be the exception to the rule. 

http://nsidc.org/arcticseaicenews/2012/08/a-summer-storm-in-the-arctic/

Low pressure systems over the Arctic Ocean tend to cause the ice to diverge or spread out and cover a larger area. These storms often bring cool conditions and even snowfall. In contrast, high pressure systems over the Arctic cause the sea ice to converge. Summers dominated by low pressure systems over the central Arctic Ocean tend to end up with greater ice extent than summers dominated by high pressure systems.

However, the effects of an individual strong storm, like that observed in early August, can be complex. While much of the region influenced by the August cyclone experienced a sudden drop in temperature, areas influenced by winds from the south experienced a rise in temperature. Coincident with the storm, a large area of low concentration ice in the East Siberian Sea (concentrations typically below 50%) rapidly melted out. On three consecutive days (August 7, 8, and 9), sea ice extent dropped by nearly 200,000 square kilometers (77,220 square miles). This could be due to mechanical break up of the ice and increased melting by strong winds and wave action during the storm. However, it may be simply a coincidence of timing, given that the low concentration ice in the region was already poised to rapidly melt out.

 

 

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2 hours ago, ORH_wxman said:

Yeah it's actually a pretty compact ice pack right now. I think the cyclone perhaps has just slowed the peripheral melting. 

Though bluewave is correct that typically cyclones over the CAB try and disperse the ice. But the concentration hasn't suffered even if it is doing that. 

I think this storm is less windy than the 2012 event...pressures are a little bit more diffuse, as there is not nearly as much gradient.

Also, 850s are somewhat colder with this storm. There is a large area of -10C 850s and a high concentration ice pack, so there isn't the tearing apart effect that 2012 had on broken up, mushy ice. Instead, the cold is refreezing the periphery and the ice may spread out a bit.

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It's impressive to see -10C 850s reaching the Siberian coast with sub-freezing 850s into Scandinavia in mid-August.

The effect of the storm may be more detrimental as it drifts towards Eurasia and strengthens..it's only like 1000mb over the CAB now.

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On 8/9/2017 at 10:09 PM, ORH_wxman said:

Cryosphere Today...it was a webpage from U Illinois that tracked sea ice area from the SSMI/S satellite. NSIDC uses the same one but they don't really show much data on area...all their graphs are extent. CT put the area in graphical format and also in tabular format. But it stopped transmitting data sometime in early 2016...at first they said they were going to be back soon but then the site went dark and it never updated. 

Area is nice to use because it tends to be a better predictor of extent 30-60 days out than extent itself is...but not having CT's easy-to-read data is really annoying. 

That's where I used to go all the time, I just didn't know that was the acronym you were using. I do miss it as well. Much more detail and good anomaly charts as well.

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On 8/10/2017 at 0:57 PM, bluewave said:

There may also be a higher degree of uncertainty in the PIOMAS data compared to other years. But we saw how the the PIOMAS and NSIDC extent widely diverged in 2013 compared to the 2007 season. Lower PIOMAS in 2013 vs 2007,but the cool 2013 summer resulted in a much higher higher September extent than 2007.

http://nsidc.org/arcticseaicenews/2017/03/

It was a very warm autumn and winter. Air temperatures at the 925 hPa level (about 2,500 feet above sea level) over the five months spanning October 2016 through February 2017 were more than 2.5 degrees Celsius (4.5 degrees Fahrenheit) above average over the entire Arctic Ocean, and greater than 5 degrees Celsius (9 degrees Fahrenheit) above average over large parts of the northern Chukchi and Barents Seas. These overall warm conditions were punctuated by a series of extreme heat waves over the Arctic Ocean.

Data from the European Space Agency’s CryoSat-2 satellite indicate that this winter’s ice cover may be only slightly thinner than that observed at this time of year for the past four years. However, an ice-ocean model at the University of Washington (PIOMAS) that incorporates observed weather conditions suggests the volume of ice in the Arctic is unusually low.

This year has been cool like 2013 so the volume and extent data are not inconsistent.

ncep75-90N2017.gif

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15 hours ago, chubbs said:

This year has been cool like 2013 so the volume and extent data are not inconsistent.

 

Much cooler summer regime since 2013 with low pressure dominating instead of high pressure.

Likely quite a bit of snow has fallen from this Arctic cyclone... Wish the polar bears could report obs :) [Map: esrl.noaa.gov/psd/people/amy…]pic.twitter.com/nrL6U5LplZ

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Can gradually see the late season ice pack of the next decade taking shape this time of year. 2016 and this year are good examples with a solid compacted half moon-shaped slab up against the CAA where the remaining MYI is located and an arc of weakened FYI from the Beaufort side right across the pole. A warmer summer would have melted that arc and left the MYI in place.

Weather gets much more hostile over the next few days, which will open the Pacific bite up even more, but it's much too late in the season for any of the compacted FYI/MYI to be melted away. It could definitely make a run at tying last year or 2007, though and leave a lot of scattered patches at the minimum. As we saw last year, that tends to re-freeze pretty quickly in late Sep and Oct. Just not quite warm enough to maintain open ocean that far north yet.

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NSIDC sea ice extent is up 22 thousand Kilometers squared. We are down 26 thousand kilometers squared over the past two days. The longitudinal and latitudinal positioning of the ice, along with the high compaction ratio will make for a very slow melt rate for the rest of the ice melt season.

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/N_seaice_extent_daily_v2.1.csv 

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Update for 2017....

 

Extent is still tracking pretty low...basically in a dead heat right now with 2016 for 4th lowest, though I would be surprised if it kept up pace since 2016 had breathtaking losses late in the month with a ton of vulnerable nearly-melted-out ice in the ESS and managed to finish 2nd lowest...2017 has no such vast areas so vulnerable, so we'd expect a slowdown relative to 2016. That said, there is still room for a pretty low result, top 5 lowest is still definitely within reach and you still cannot quite rule out 2nd lowest if the weather was absolutely hostile to the max. But the race may be more with 2011/2015.

 

Area is a bit of a different story...the ice is pretty compact...not nearly as spread out as some other years. So area is running higher than extent in the rankings.

 

Here are the August 17th (based on 8/16 satellite scan) area numbers by year:

2017: 3.69 million sq km

2016: 3.26

2015: 3.51

2014: 4.53

2013: 4.10

2012: 2.92

2011: 3.32

2010: 3.92

2009: 3.95

2008: 3.67

2007: 3.23

 

 

2008 is currently the closest match, then 2015 is next closest. 2008 finished at 3.00 million sq km while 2015 finished at 3.09 million sq km. The ice pack is currently more compact than both of those years so it wouldn't be shocking if it finished higher...however, it is also probably thinner out on the PAC side, so that could offset the compactness some and still produce area losses that are more comparable to a dispersed ice pack....weather of course will be a factor too, so we'll just have to see. A finish anywhere from 3rd lowest to 7th lowest is still plausible on area...I think 2012 and 2016 are now safely out of reach as well as 2009, 2013, and 2014.

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One of the greatest early August anomaly decreases on the PIOMAS with the cool and stormy pattern in the Arctic. Also among the strongest polar vortex patterns for the first half of August.  

 

piomas-trnd3.png_thumb.png.d8285532028186bea25471e51bcb4254.png

 

500.gif.bb8766dcaf894f53e7a08a84a654bf15.gif

 

 

 

 

 

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Apologies if I'm splitting hairs, Bluewave, but August didn't see an increase in Arctic SIV, it saw a decrease in the anomaly.  Arctic SIV continued to drop, albeit at a slower rate.  

piomas-trnd4.png?attachauth=ANoY7crTRE2w7YfWjY1nsn3lm-zU9n1mdeGIzh_1dPVYFC8Oi8l7cGv7F1hXAB4I17YbKqvk4IDeY5aMvNw-TN1eem8rjhhvHmaLXrELIch0sVjC83w42JhhnmCpF-jYSJigemS6j_vKJLSkVSq7w40-O8l-JZvePW6q_i2SGYKIN04Atl6rHgrKo_wVaOx3dEcVAF_AqdxK0PFMTA5cJFxsWMwZoqZocBlUFa8WhK7h2rht7XULX2G6GRWGaRCo8UEsMinWLN1H&attredirects=0

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7 hours ago, PhillipS said:

Apologies if I'm splitting hairs, Bluewave, but August didn't see an increase in Arctic SIV, it saw a decrease in the anomaly.  Arctic SIV continued to drop, albeit at a slower rate.  

 

No problem. We may be able to further decline the anomaly if we can avoid the historic warmth that we saw last Oct-Dec. That may set the volume up to come into next summer a little better than we saw this year. The state of the sea ice next summer will then come down whether the less hostile 2013-2017 stronger polar vortex pattern can prevail another year. Or the 2007-2012 dipole pattern makes a return. Be interesting to see how many more years the 2012 can hold on. The reversal of the summer pattern in 2013 turned out to be a surprise that people didn't think was possible during the fall of 2012. But some studies came out in early 2013 that mentioned this possibility. Long term sea ice decline with increases or decreases in the short term rate.

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We are currently in an unprecedented slow down in this melting season. Looking at JAXA sea ice extent data for the past 5 days (8.14-8.20), here is how this year compares to previous years. All of this in a time frame were weather was considered unfavorable by most. Where is the heat? 

d4pmU76.png

78499  Kilometers Squared (2017)    
250806 Kilometers Squared (2016)
271380 Kilometers Squared (2015)    
201212 Kilometers Squared (2014)
170241 Kilometers Squared (2013)
323143 Kilometers Squared (2012)    
214782 Kilometers Squared (2011)    
171913 Kilometers Squared (2010)    
242082 Kilometers Squared (2009)    
235464 Kilometers Squared (2008)
209292 Kilometers Squared (2007)    
236247 Kilometers Squared (2006)    
174575 Kilometers Squared (2005)    
294866 Kilometers Squared (2004)    
125356 Kilometers Squared (2003)    
223099 Kilometers Squared (2002)    
207152 Kilometers Squared (2000's Average)
141827 Kilometers Squared (1990's Average)    
106000 Kilometers Squared (1980's Average)
 

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26 minutes ago, Weatherdude88 said:

We are currently in an unprecedented slow down in this melting season. Looking at JAXA sea ice extent data for the past 5 days (8.14-8.20), here is how this year compares to previous years. All of this in a time frame were weather was considered unfavorable by most. Where is the heat? 

 


 

We had a really compact ice pack with very few regions of very low concentration so it is not a huge surprise that we've seen a stall in extent while area has resumed its drop (after stalling earlier). The weather was never that great for losing a lot of extent this past week...we did get that cyclone earlier, but it never got nearly as intense as the 2012 cyclone and it occurred over a pack that was not nearly as shredded as 2012.

 

 

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55 minutes ago, ORH_wxman said:

We had a really compact ice pack with very few regions of very low concentration so it is not a huge surprise that we've seen a stall in extent while area has resumed its drop (after stalling earlier). The weather was never that great for losing a lot of extent this past week...we did get that cyclone earlier, but it never got nearly as intense as the 2012 cyclone and it occurred over a pack that was not nearly as shredded as 2012.

 

 

 

On 8/15/2017 at 8:51 AM, Weatherdude88 said:

NSIDC sea ice extent is up 22 thousand Kilometers squared. We are down 26 thousand kilometers squared over the past two days. The longitudinal and latitudinal positioning of the ice, along with the high compaction ratio will make for a very slow melt rate for the rest of the ice melt season.

 

Hence, my earlier comment. Extent was bound to fall more in line with area before the end of the melt season, where historically we generally see a less compact northern hemisphere cryosphere. The positioning of the high latitude ice was "icing" on the cake. We may indeed see a record early minimum this year. My prediction is August 31st. Let's see what happens.

 

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6 minutes ago, Weatherdude88 said:

 

 

Hence my earlier comment. Extent was bound to fall more in line with area before the end of the melt season, where historically we generally see a less compact northern hemisphere cryosphere. The positioning of the high latitude ice was "icing" on the cake. We may indeed see a record early minimum this year. My prediction is August 31st. Let's see what happens.

 

We would need perfect weather I think to get a minimum in August for extent...I don't think it's ever happened in the jaxa record. Earliest I could find was 9/1 in 1997...looks like 1988 was 9/2. It admittedly might be a little easier to get a min in August with less ice extent than previous years if there's some open water pretty close to the pole...as that will tend to freeze much earlier than the peripheral areas. We sort of saw this last year when we had a min on 9/7...pretty early.

Area has twice had minimums in August...2005 and 1986 I believe. Both were on August 31st I believe.

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20 hours ago, ORH_wxman said:

We would need perfect weather I think to get a minimum in August for extent...I don't think it's ever happened in the jaxa record. Earliest I could find was 9/1 in 1997...looks like 1988 was 9/2. It admittedly might be a little easier to get a min in August with less ice extent than previous years if there's some open water pretty close to the pole...as that will tend to freeze much earlier than the peripheral areas. We sort of saw this last year when we had a min on 9/7...pretty early.

Area has twice had minimums in August...2005 and 1986 I believe. Both were on August 31st I believe.

 

I would be more impressed with early minimums decades ago when the ice was much more widespread and therefore had more vulnerable ice to give back. 

 

Getting an early minimum when all the easy ice is already melted and all we have is a compact core left is not as impressive, it's almost expected.  

 

What is impressive is how we continue to shed ice most years despite losing all the vulnerable ice well before the end of the season. Shows you how pathetic the cryosphere has been over the last 15 years. 

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44 minutes ago, Sundog said:

 

I would be more impressed with early minimums decades ago when the ice was much more widespread and therefore had more vulnerable ice to give back. 

 

Getting an early minimum when all the easy ice is already melted and all we have is a compact core left is not as impressive, it's almost expected.  

 

What is impressive is how we continue to shed ice most years despite losing all the vulnerable ice well before the end of the season. Shows you how pathetic the cryosphere has been over the last 15 years. 

There hasn't been any trend in minimum date since records began...but it's possible we start seeing it trend earlier if we get more years with open water close to the pole. But years like 2007 and 2012 had pretty late minimums...so the open waters those years did not facilitate early mins. It is still almost entirely weather dependent.

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1 hour ago, Sundog said:

 

I would be more impressed with early minimums decades ago when the ice was much more widespread and therefore had more vulnerable ice to give back. 

 

Getting an early minimum when all the easy ice is already melted and all we have is a compact core left is not as impressive, it's almost expected.  

 

What is impressive is how we continue to shed ice most years despite losing all the vulnerable ice well before the end of the season. Shows you how pathetic the cryosphere has been over the last 15 years. 

 

Lol...ok

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