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Gray-Wolf

Arctic Sea Ice Discussion 2017 - The Melt Season

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Posted (edited)

Well we appear to be passed max ice for the winter 2016/17 .NSIDC put this as occurring on March 7th and was the lowest ever recorded for that date.

To me this is a very important melt season yet seen with the potential to fall to the lowest ,across all measures, if we see any fine stretches of weather over the season.

2017 is also the earliest possible return for the 'perfect melt storm'......... we don't need one thanks very much!!!

Edited by reef
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On 27/03/2017 at 13:06, Gray-Wolf said:

Well we appear to be passed max ice for the winter 2016/17 .NSIDC put this as occurring on March 7th and was the lowest ever recorded for that date.

To me this is a very important melt season yet seen with the potential to fall to the lowest ,across all measures, if we see any fine stretches of weather over the season.

2017 is also the earliest possible return for the 'perfect melt storm'......... we don't need one thanks very much!!!

Are we seeing early fragmentation that's led to a small upward blip

We go into a new melt season with a poor ice pack

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Could the mods close down the 'refreeze' thread as I'm sure we all agree we are into the Arctic Melt phase.

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Continuing on from the discussion in the old thread...

Longer term you have to look at where any recovery might come from. The ENSO forecast suggests yet another moderate or strong El Nino this winter, so we could yet again be looking at a globe warmer than the long-term trend. That's more heat being transferred north when the ice is still suffering from the hit of the last 12 months.

I wonder if this current period will look like another step change downwards similar to around 2007?

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I think by the end of May we will have proper sight of the damage the past winter did to the growth/thickening of the ice. If we see open water above 75N by late May I reckon we are in trouble!

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https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2017-04-22&z=3&v=-2283008,-310784,-1583616,15872

Beaufort gyre has been spinning and you can see the damage to the ice there? I've been watching the ice in Lincoln break pff the ice arch at the start of nares and the ice quickly re=sizes back down to the small floes that we finished last melt season with? If the ice in the rest of Beaufort does this then we will see the degradation over the coming weeks as the floes we see in the above sat image break down.

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11 minutes ago, BornFromTheVoid said:

Update for the week to April 22nd

The current 5 day trailing average is on 13,587,000km2 while the 1 day extent is at 13,493,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -935,000km2, a decrease from -966,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -515,000km2, an increase from -445,000km2 last week. We're currently 2nd lowest on record, down from lowest last week.

T7AfKY0.png

The average daily change over the last 7 days was -32.9k/day, compared to the long term average of -37.3k/day, and the 07, 11 and 12 average of -22.8k/day.
The average long term change over the next week is -40.7k/day, with the 07, 11, and 12 average being -44.2k/day.

HW2AEwP.png

The extent loss so far this April is the 14th smallest record. To achieve the largest loss, a drop of at least 130.0k/day is required (more than -157.4k/day with with single day values), while the smallest drop requires a loss of less than 14.4k/day (less than 3.5k/day with single day values) and an average loss requires a drop of 65.7k/day (-71.9k/day with single day values).

FOmhzK1.png

 

11 minutes ago, BornFromTheVoid said:

Update for the week to April 22nd

The current 5 day trailing average is on 13,587,000km2 while the 1 day extent is at 13,493,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -935,000km2, a decrease from -966,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -515,000km2, an increase from -445,000km2 last week. We're currently 2nd lowest on record, down from lowest last week.

T7AfKY0.png

The average daily change over the last 7 days was -32.9k/day, compared to the long term average of -37.3k/day, and the 07, 11 and 12 average of -22.8k/day.
The average long term change over the next week is -40.7k/day, with the 07, 11, and 12 average being -44.2k/day.

HW2AEwP.png

The extent loss so far this April is the 14th smallest record. To achieve the largest loss, a drop of at least 130.0k/day is required (more than -157.4k/day with with single day values), while the smallest drop requires a loss of less than 14.4k/day (less than 3.5k/day with single day values) and an average loss requires a drop of 65.7k/day (-71.9k/day with single day values).

FOmhzK1.png

BFTV.  Thank you for the regular stats but I wonder is it possible to make comment about them from time to time. Might assist in my interpretation. Cold or not so cold figures does not entirely explain to me how things are moving in a negative or positive way. 

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Discussion, commentary etc is in this thread Snipper!

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I'm sure we have plenty seasoned ice watcher that would be happy to try and answer any queries you have Snipper?

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1 hour ago, Gray-Wolf said:

I'm sure we have plenty seasoned ice watcher that would be happy to try and answer any queries you have Snipper?

Thanks. Just suggesting a paragraph of conclusion should be added where mainly hard data is posted. This would go nicely with the comments yourself and others make and might bring about more discussion. Just a thought. 

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On 2017-4-25 at 10:58, Snipper said:

Thanks. Just suggesting a paragraph of conclusion should be added where mainly hard data is posted. This would go nicely with the comments yourself and others make and might bring about more discussion. Just a thought. 

There is a thread where BFTV kindly provides weekly updates and this thread for 'discussions'. Obviously were comparing apples and pears and when  one mentions extent losses being average in April so far it can be misleading as your including the 1980s when it was 1.500.000 higher at this time of year, Areas melting now wouldn't have been melting out until 3/4 weeks time in 1980s. Melt losses then were probably going on at much higher latitudes.

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If we over lay the 'average' volume drop over melt season in the 80's on today's volume measure you'll see that we have a problem!

to me there must come a point that means total melt out? Once we are ice free we will start to see that if we have 'X' amount of ice by mid July the open water will take it no matter the weather and we are now starting to move into that position. If we see a strong start to this melt season it could get very interesting by mid Aug this year!

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On 20/04/2017 at 18:44, reef said:

Continuing on from the discussion in the old thread...

Longer term you have to look at where any recovery might come from. The ENSO forecast suggests yet another moderate or strong El Nino this winter, so we could yet again be looking at a globe warmer than the long-term trend. That's more heat being transferred north when the ice is still suffering from the hit of the last 12 months.

I wonder if this current period will look like another step change downwards similar to around 2007?

Could you please tell me where I can find this ENSO forecast.

 

Thank you

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PIOMAS has updated and its still as grim as it was last month with only a very slight reduction in the anomaly compared to every other year on record:

http://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAnomalyCurrentV2.1_CY.png

If this gap doesn't close by Autumn then its hard to see how we won't beat 2012 for extent and area aswell, as the reduced thickness is very even over the basin.

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Posted (edited)

Arctic sea ice extent currently looking less exceptionally low according to NSIDC, creeping within 2 standard deviations of the mean:

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

Despite this, though, I think the 2012 record is still potentially under serious threat, due to the continued record sea ice volume anomaly, and the emergence of large areas of low sea ice concentration around the edges of the ice sheet.  I'm expecting May 2017 to have a similarly high rate of melt to May 2016, which would leave us comfortably at second lowest by the end of the month, and ahead of 2012.

Edited by Thundery wintry showers

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IJIS extent now up to 4th lowest but I do not think this is any cause for celebration as , to me, it is telling us what any look at the current sat images of the basin tell us? The way extent is measured means that as the pack falls apart its 'extent' grows. The mess of a Pack we ended last year with is now revealing itself as this years extra thin, extra weak , extra warm FY ice slumps away.

We saw a lot of WACCy weather snow fall on sections of the pack early last refreeze. As temps/dew points rise to melt levels we could see extensive melt ponding over such areas. The ice the snow fell on was our bast ice at then end of last year ( it survived) but melt ponds on its surface lowers its albedo and so brings early melt to our best ice?

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Well PIOMAS for April is in and its another record low month keeping in the 2 sigma band again ( been there all winter?) .

We saw a bad year for the ice in 07' , 5 years later we saw a shocker for the ice ( 2012). We are now 5 years later.........

2007 went down as a 'Perfect Melt Storm'. We were told that they turn up every 10 to 20 years and that the 2 before 07' were both only 10 years apart.

Long range forecasts give high pressure over the basin right through until the end of June ( when the forecast ends) That would be the worse possible start to this melt season with lots of snow over the older ice from the WACCy dumpings in October/November to bring about major melt pond formation over the last of the good ice with high melt forcings to then follow. If the forecast were to verify we would be in very bad shape for the rest of the season.

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There is ice free and ice free though?

Currently we are looking at becoming 'practically ice free' which would see less than 1 million square km of ice in the basin. The ice would re-grow in winter. A move to a year round ice free Arctic is the logical conclusion of warming and 2070 might be a tad early to expect such?

That said prior to 07' most scientists were agreed that the sub million pack would occur by the centuries end. After 07' that was rapidly wound in with a range from 2016 ( plus or minus 3 years) to mid century. Since last melt season ( and the non winter that followed) folk have voiced real concerns that were we to see strong melting and export conditions across the basin this year we stand a chance of going sub 1 million this year. With the earliest return of the Perfect Melt storm synoptic being this year we might be in for some fun!

http://www.economist.com/news/leaders/21721379-current-trends-arctic-will-be-ice-free-summer-2040-arctic-it-known-today

above is an economist article on the loss of the Arctic........

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The latest report suggests late 2030s, not 2070, the Arctic may be largely free of ice during summer. Here's a link to the summary for policy makers version (not sure where the full one is): http://www.amap.no/documents/doc/Snow-Water-Ice-and-Permafrost.-Summary-for-Policy-makers/1532

As GW mentioned. the general consensus position has shifted from ice free September (<1 million km2) by the end of this century to around mid century over the last 20 years, as the sea ice has declined quicker than most projections. Of course there will always be random studies suggesting early or later dates, which is why looking at the consensus is still important.

You also need to consider whether a study is looking at extent, area, volume, a single day, month or season. The latest report mentions ice free "summer" by the late 30s, rather than just an ice free September, which would suggest an ice free September perhaps in the next decade, well ahead of the consensus position. Once more though, we'd need to look at the full report to see exactly what they mean by "summer" and "ice free".

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