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philopek

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Re: The 2019 melting season
« Reply #6100 on: August 26, 2019, 04:06:50 PM »
The European model has been hinting at the possibility of an absolute bomb cyclone in the first week of September in the Laptev - East Siberian sea region. The exceptionally warm water there would potentially add extra  intensity to a storm in that region so it's possible that we could see a record deep low pressure for September this year. However, at this time, there's no reliability in forecasts greater than 5 days so this is just something that is possible given the SSTs and atmospheric dynamics this year.

Absolutely, if this becomes a reality we can lose up to 700'000k in a few days because :

- right spot,
- rather stationary
- still dropping, just couldn't get a later map
- right angle of attack (45-90°)
- temps above or around 0°
- receiving sea is Barents/Kara that's in full uproar itself at the same time.

and that's about to start in 5 days, not reliable as you say but also not totally off the possibility
and if this will last 4-5 days it will certainly finish 90% of the remaining Laptev ice off that accounts
for about 500k +/- something

EDIT: The low is traveling kind of in circle instead of a straight trajectory, the attached image shows one of the latest available while still dropping and before and probably after the laptev rubble is more directly attacked.
« Last Edit: August 26, 2019, 04:15:47 PM by philopek »

pearscot

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Re: The 2019 melting season
« Reply #6101 on: August 26, 2019, 06:41:49 PM »
I wish I knew wtf was going on under all those clouds, especially after those series of low pressure storms which appeared to hit the CAB. I really don't foresee any records being broken, but I feel like all the wave action combined with the shattered ice *must* do something. I keep thinking I will see some flash melting with the thin/silk strands on the periphery, yet the seem to be more resilient than I thought. Well, the season isn't over and if there is going to be a clear day I have a feeling the ice has at least been made less compact than it was prior.
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Milwen

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Re: The 2019 melting season
« Reply #6102 on: August 26, 2019, 06:45:47 PM »
HYCOM Ice Thickness August 27 - September 2


philopek

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Re: The 2019 melting season
« Reply #6103 on: August 26, 2019, 06:48:59 PM »
I wish I knew wtf was going on under all those clouds, especially after those series of low pressure storms which appeared to hit the CAB. I really don't foresee any records being broken, but I feel like all the wave action combined with the shattered ice *must* do something. I keep thinking I will see some flash melting with the thin/silk strands on the periphery, yet the seem to be more resilient than I thought. Well, the season isn't over and if there is going to be a clear day I have a feeling the ice has at least been made less compact than it was prior.

There are pretty large areas where one can peek through and between the clouds.
Just use the link and zoom in to your area of interest.

Further I recommend to check charts and Uni-Bremen to get the bigger picture that is:

- more dispersion
- not much has changed in general while the impact of the storm is visible, just not that huge

https://worldview.earthdata.nasa.gov/?v=-2957052.5726380534,-1209796.499247358,1140390.966957035,1022179.9762578404&p=arctic&t=2019-08-20-T03%3A37%3A36Z&t1=2019-08-25-T04%3A33%3A56Z&l=Reference_Labels(hidden),Reference_Features(hidden),Coastlines,MODIS_Aqua_CorrectedReflectance_Bands721(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor&l1=Reference_Labels(hidden),Reference_Features(hidden),Coastlines,MODIS_Aqua_CorrectedReflectance_Bands721,VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor&ca=false&cm=spy
« Last Edit: August 26, 2019, 06:57:19 PM by philopek »

blumenkraft

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Re: The 2019 melting season
« Reply #6104 on: August 26, 2019, 10:03:45 PM »
How many days of increase in a row count as a freezing season?? ;)

Also the 5-day average is lower than today's number.

I think we once all came to terms that we can use the best available but nevertheless debatable numbers for the sake of comparing apples with apples.

Nevertheless I suggest that you won't further insist that the melting season has ended 3 days ago because in that case I would suggest to label those numbers as misleading and rely on those with a higher resolution that show a drop in the range of the average for the day of the year.

On the other hand some may find it interesting to question and discuss everything but the propose that you open a separate thread to keep this one on track.

Neither temperatures nor forecasts nor events imply that a refreeze could happen except perhaps surface water (melt ponds) with fresh water but that would only ad to "Area" which apparently indeed happens.

Philopek, i was joking.  ::)
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colchonero

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Re: The 2019 melting season
« Reply #6105 on: August 26, 2019, 10:04:25 PM »
And that bomb cyclonic event has suddenly disappeared in 12z model runs today.

blumenkraft

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Re: The 2019 melting season
« Reply #6106 on: August 26, 2019, 10:31:18 PM »
HYCOM Ice Thickness August 27 - September 2

Well, where Hycom sees thick ice, at the shores of Ellesmere Island, there is quite a lot of open water now.
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petm

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Re: The 2019 melting season
« Reply #6107 on: August 26, 2019, 11:00:14 PM »
And that bomb cyclonic event has suddenly disappeared in 12z model runs today.

Models are being jumpy. Who knows what'll actually come, but the way this season has gone, probably nothing.

philopek

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Re: The 2019 melting season
« Reply #6108 on: August 26, 2019, 11:08:34 PM »
And that bomb cyclonic event has suddenly disappeared in 12z model runs today.

Models are being jumpy. Who knows what'll actually come, but the way this season has gone, probably nothing.

Yeah, has been replaced with a HIGH pressure of >1020hPa

I'd say pole vault kind of jumpy ;)

Aleph_Null

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Re: The 2019 melting season
« Reply #6109 on: August 26, 2019, 11:20:41 PM »
I struggle to reconcile the near-flatlining of some metrics with what I see in Worldview, and particularly what I see in petm & Aluminium's invaluable animated contributions. This is my morning meditation, staring at those, and I don't see a single day yet when the ice doesn't seem like it's still fading. Lately, it sure is jostling about mightily. NE of Greenland looks very weird to me.

pauldry600

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Re: The 2019 melting season
« Reply #6110 on: August 26, 2019, 11:29:18 PM »
Looking at ice every year less and less seems to be holding on to land. I think before we see a year with no ice at Summers end we will see one with a circle of blue all the way round.

This year is going to finish close to exactly 4m IMO of guessing randomly

However might go lower and end around September 20th.

sailor

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Re: The 2019 melting season
« Reply #6111 on: August 26, 2019, 11:52:09 PM »
The slow down started two weeks ago when increases in concentration were reported first, perhaps a sign that melting momentum was being exhausted.
However there was still potential for extent losses, and the weather I would think was conductive to those losses. But did not happen. Yet I expect more significant drops before mid September. Tomorrow’s concentration map will show an even more disperse and degraded pack than Today’s.
Edit: image is tweaked to reveal intact areas of ice pack. Original:
ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/Arc_latest_yesterday_AMSR2_3.125km.png
« Last Edit: August 27, 2019, 12:01:45 AM by sailor »
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philopek

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Re: The 2019 melting season
« Reply #6112 on: August 26, 2019, 11:57:55 PM »
I struggle to reconcile the near-flatlining of some metrics with what I see in Worldview, and particularly what I see in petm & Aluminium's invaluable animated contributions. This is my morning meditation, staring at those, and I don't see a single day yet when the ice doesn't seem like it's still fading. Lately, it sure is jostling about mightily. NE of Greenland looks very weird to me.

In this case i recommend to use satellite imagery to get more input for better assessment. If you do it on a daily basis you'll get the whole picture, rarely at a glace because there are often more clouds than blue skies. Nevertheless one can get a reasonable idea as to what means what on those maps.

Satellites (preset):

https://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=12&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190614235053&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=eumetsat_natural_color&x=18167.7294921875&y=20649.22265625

https://worldview.earthdata.nasa.gov/?v=-7707446.425196851,-4198432.251968504,7707446.425196851,4198432.251968504&p=arctic&t=2019-07-27-T00%3A00%3A00Z&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels,Reference_Features(hidden),Coastlines

https://worldview.earthdata.nasa.gov/?v=481065.626358435,-741747.5892417862,762601.5131812957,-588388.1907956966&p=arctic&t=2019-08-20-T03%3A37%3A36Z&t1=2019-08-20-T10%3A33%3A56Z&l=Reference_Labels(hidden),Reference_Features(hidden),Coastlines,MODIS_Aqua_CorrectedReflectance_Bands721(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor&l1=Reference_Labels(hidden),Reference_Features(hidden),Coastlines,MODIS_Aqua_CorrectedReflectance_Bands721,VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor&ca=false&cm=spy

https://zoom.earth/#view=80.6,-102.2,4z/date=2019-08-24,am/layers=labels,crosshairs

Shared Humanity

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Re: The 2019 melting season
« Reply #6113 on: August 27, 2019, 12:53:59 AM »
The slow down started two weeks ago when increases in concentration were reported first, perhaps a sign that melting momentum was being exhausted.
However there was still potential for extent losses, and the weather I would think was conductive to those losses. But did not happen. Yet I expect more significant drops before mid September. Tomorrow’s concentration map will show an even more disperse and degraded pack than Today’s.
Edit: image is tweaked to reveal intact areas of ice pack. Original:
ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/Arc_latest_yesterday_AMSR2_3.125km.png

I would like to go on record as saying that ice looks worse than I have ever seen it at the end of a melt season.

sailor

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Re: The 2019 melting season
« Reply #6114 on: August 27, 2019, 01:02:48 AM »
The slow down started two weeks ago when increases in concentration were reported first, perhaps a sign that melting momentum was being exhausted.
However there was still potential for extent losses, and the weather I would think was conductive to those losses. But did not happen. Yet I expect more significant drops before mid September. Tomorrow’s concentration map will show an even more disperse and degraded pack than Today’s.
Edit: image is tweaked to reveal intact areas of ice pack. Original:
ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/Arc_latest_yesterday_AMSR2_3.125km.png

I would like to go on record as saying that ice looks worse than I have ever seen it at the end of a melt season.
Not even excluding 2016?
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icefisher

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Re: The 2019 melting season
« Reply #6115 on: August 27, 2019, 02:49:49 AM »
What about volume?  We need 500 well placed floats capable of measuring ice thickness.  A simplified system making just a few measurements per year around April 1 and Oct 1 should not cost much.  I envision a retractable centimeter marked cable in a waterproof housing operating with a spring tension and a top and bottom paddle hook for holding on as ice grows and shrinks.  Ice that goes completely away results in a zero measurement. 

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Re: The 2019 melting season
« Reply #6116 on: August 27, 2019, 02:53:03 AM »
What about volume?  We need 500 well placed floats capable of measuring ice thickness.  A simplified system making just a few measurements per year around April 1 and Oct 1 should not cost much.  I envision a retractable centimeter marked cable in a waterproof housing operating with a spring tension and a top and bottom paddle hook for holding on as ice grows and shrinks.  Ice that goes completely away results in a zero measurement.
What's wrong with PIOMAS? It isn't perfect but paradoxically *consistent* imperfection leads to valid comparisons even if the baseline may not be 100%.

Paul

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Re: The 2019 melting season
« Reply #6117 on: August 27, 2019, 03:16:50 AM »
The slow down started two weeks ago when increases in concentration were reported first, perhaps a sign that melting momentum was being exhausted.
However there was still potential for extent losses, and the weather I would think was conductive to those losses. But did not happen. Yet I expect more significant drops before mid September. Tomorrow’s concentration map will show an even more disperse and degraded pack than Today’s.
Edit: image is tweaked to reveal intact areas of ice pack. Original:
ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/Arc_latest_yesterday_AMSR2_3.125km.png

I would like to go on record as saying that ice looks worse than I have ever seen it at the end of a melt season.
Not even excluding 2016?

Imo, 2016 is probably worse in respect of ice concentration and of course just how far north TRUE open water went  with the slow melt in the laptev saving the ice extent numbers looking even worse than they were. This year has no arm stretching out to the ESS which has impacted the extent numbers but for me what is telling this year is just how low we have been constantly during the summer and how one warm month(June) in the ESS really provided the momentum for the rest of the summer to really melt the ice in that region.

Whilst there will be no records this year, extent could still go below 4 million and that is noteworthy enough for me, the race is on in that respect.

bbr2314

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Re: The 2019 melting season
« Reply #6118 on: August 27, 2019, 03:18:00 AM »
Imo, 2016 is probably worse in respect of ice concentration and of course just how far north TRUE open water went  with the slow melt in the laptev saving the ice extent numbers looking even worse than they were. This year has no arm stretching out to the ESS which has impacted the extent numbers but for me what is telling this year is just how low we have been constantly during the summer and how one warm month(June) in the ESS really provided the momentum for the rest of the summer to really melt the ice in that region.

I feel like maybe we should stop comparing 2016's minimum with 2019's late August appearance especially when models are forecasting cyclonic activity of varying potential in the medium-long range.

<I've snipped irrelevant text. Don't be such a lazy quoter; N.>
« Last Edit: August 27, 2019, 10:09:57 AM by Neven »

FishOutofWater

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Re: The 2019 melting season
« Reply #6119 on: August 27, 2019, 03:28:11 AM »
Heat is radiating out from the cloudtops and above so the polar atmosphere is becoming increasingly unstable as we move into September. The models are struggling to capture what's happening more than 3 or 4 days out.

There's still the potential to melt out dispersed ice on the Siberian side of the pole but the horse race is now for the second or third position. It's a good thing that 2012 is looking unbeatable. The fires in Siberia and the Amazon have been depressing enough. We don't need to see any new sea ice records this year to get the message across that the climate is in trouble.

Juan C. García

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Re: The 2019 melting season
« Reply #6120 on: August 27, 2019, 05:15:36 AM »
I don't know how much ice will melt, but it really looks in bad shape. Like on box, maybe the ring will save it. Or maybe not. Just a coin in the air.
« Last Edit: August 27, 2019, 05:22:12 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

marcel_g

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Re: The 2019 melting season
« Reply #6121 on: August 27, 2019, 05:45:02 AM »
...

There's still the potential to melt out dispersed ice on the Siberian side of the pole but the horse race is now for the second or third position. It's a good thing that 2012 is looking unbeatable. The fires in Siberia and the Amazon have been depressing enough. We don't need to see any new sea ice records this year to get the message across that the climate is in trouble.

Indeed.

petm

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Re: The 2019 melting season
« Reply #6122 on: August 27, 2019, 05:48:18 AM »
Aug 20-26

5-day min v. original Bremen

Some reversal of recent trends; expect extent to drop a bit and area to continue dropping. Alaskan side: took a significant hit from the storm yesterday (even though it wasn't big), with both compaction and melt. Asian side: Swiss cheese holes are rapidly expanding -- it wouldn't take much to drop a large area below 15%. Atlantic side: continues stable (minor advance). CAA: doesn't seem to be doing much -- I guess the storm a few days ago, despite significant local effects in some places, was too brief to be reflected much in overall area/extent.
« Last Edit: August 27, 2019, 06:10:31 AM by petm »

marcel_g

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Re: The 2019 melting season
« Reply #6123 on: August 27, 2019, 05:57:03 AM »
...
Tomorrow’s concentration map will show an even more disperse and degraded pack than Today’s.
Edit: image is tweaked to reveal intact areas of ice pack. Original:
ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/Arc_latest_yesterday_AMSR2_3.125km.png

I would like to go on record as saying that ice looks worse than I have ever seen it at the end of a melt season.
Not even excluding 2016?
2016 at least had that Wrangle arm of ice in the ESS, and another big arm out in the Laptev. The ice did look terrible well into the CAB, but this year it's just looking terrible across almost all of it. I'll be really glad if this rubble can hang on until refreeze, and if those storm forecasts don't come to pass.

petm

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Re: The 2019 melting season
« Reply #6124 on: August 27, 2019, 06:02:22 AM »
I struggle to reconcile the near-flatlining of some metrics with what I see in Worldview, and particularly what I see in petm & Aluminium's invaluable animated contributions.

Glad they're soothing... ;)

Keep in mind that CAB area does continue to decline, and is easily near-record, competing with only 2012 and 2016, at least by Wipneus' method. Extent is fickle, and in the short-term can have more to do with compaction / dispersal than with the amount of ice present. It has even been suggested that high extent / low area, while not as sexy, may be the worst possible finish vis-a-vis the future health of the pack (by reducing heat escape).
« Last Edit: August 27, 2019, 06:11:26 AM by petm »

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Re: The 2019 melting season
« Reply #6125 on: August 27, 2019, 06:21:58 AM »
Yeah, I think this year is worse than 2012 overall.

Hanging onto poor satellite measurements, and specifically extent or area, seems like false optimism. The ice is most definitely in worse shape than 2012. It’s a slushy and highly mobile mess. All the old ice (>4yrs) is gone. The thick ice anchoring Greenland is gone. Volume may ultimately also be lower than 2012. But it didn’t take exceptional weather forces to achieve these results like 2012.

The conditions also seem to be setting up for a horrible refreeze season, adding up to the beginning of a new era in the Arctic Climate. A new normal.
« Last Edit: August 27, 2019, 06:54:52 AM by TeaPotty »

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Re: The 2019 melting season
« Reply #6126 on: August 27, 2019, 06:35:19 AM »
I prefer to look at 4 km Masie area it is far more accurate than the 25 km resolution data. I would like to use the 1 km data but it doesn't even go back to 2012. It shows the results of all the heat in the ocean better.

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Re: The 2019 melting season
« Reply #6127 on: August 27, 2019, 06:40:01 AM »
And its about 400000 km below 2012.

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Re: The 2019 melting season
« Reply #6128 on: August 27, 2019, 06:53:54 AM »
I prefer to look at 4 km Masie area it is far more accurate than the 25 km resolution data. I would like to use the 1 km data but it doesn't even go back to 2012. It shows the results of all the heat in the ocean better.

Absolutely! This fits well in with what I said yesterday about the JAXA extent numbers simply showing more dispersion than 2012, not less melt.

PS where did you get that graph? I was unable to find MASIE that showed more than the last 4 years.
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Re: The 2019 melting season
« Reply #6129 on: August 27, 2019, 06:56:52 AM »
Looking more closely at the Alaskan side -- holy carp, it really took a beating! Nothing but mush now in a large area. The extent numbers are very misleading. Shows how weak the ice is, when just one day of moderately bad weather does this.

https://go.nasa.gov/2PhKPFj

(NB: The comparison is from quite a while ago due to clouds. You can see through some areas on some days closer to present, if you poke around.)

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Re: The 2019 melting season
« Reply #6130 on: August 27, 2019, 07:03:49 AM »
I downloaded the data and made the graph myself. I have it automated in excel to where I just push a button and it updates. I would provide it but we can't add excel files here because they are to big of a security risk.

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Re: The 2019 melting season
« Reply #6131 on: August 27, 2019, 07:16:54 AM »

Glad they're soothing... ;)

Keep in mind that CAB area does continue to decline, and is easily near-record, competing with only 2012 and 2016, at least by Wipneus' method. Extent is fickle, and in the short-term can have more to do with compaction / dispersal than with the amount of ice present. It has even been suggested that high extent / low area, while not as sexy, may be the worst possible finish vis-a-vis the future health of the pack (by reducing heat escape).

It appears from the daily Bremen ASMR2 6.25 km grid, there has been a solidifying of the central pack from 8.25.

Expect an uptick on the CAB graph during the update in 3 hours.


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Re: The 2019 melting season
« Reply #6132 on: August 27, 2019, 07:51:21 AM »
I prefer to look at 4 km Masie area it is far more accurate than the 25 km resolution data.

 MASIE data is an adjusted value, in an easier to use format, than the initial IMS data set. 

Quote
The IMS product uses several satellite data sources including passive microwave, but it is also based on visual analysis and other data sources and undergoes a form of manual data fusion.

https://nsidc.org/data/masie/masie_faq

The human influence can make it unreliable when comparing to previous melting seasons.

Regardless, looking at 4K MASIE data, 2012 loses a monstrous 950,244 square kilometers of sea ice over the next 6 days. By comparison 2019 has lost 162,148 square kilometers of sea ice in the past 6 days.

MASIE data will likely show 2019 falling significantly behind 2012 in the next week.

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Re: The 2019 melting season
« Reply #6133 on: August 27, 2019, 08:51:07 AM »
I plotted 5 day trailing average as without it is very erratic. In the next 6 days according to this chart it only needs to lose 250000 km^2 to be in the same place. As the grey lines show 3 years of the last 14 years have enough melt from this point to make a new record. I know the grey lines are harder to see on the small graph.


The fact that a human manually determines how to count a square does create some variability. However I believe the use of multiple products instead of just one still creates a more reliable data set then a single source product with an algorithm.


It would take almost 5 days for 2012 to catch up with this year even if there is no further ice losses.

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Re: The 2019 melting season
« Reply #6134 on: August 27, 2019, 09:01:20 AM »
During this melt season there were several time when the algorithem clearly got things wrong. It assumed that melt ponds were open water. Visual and other bands made it easy to dismiss them as melt ponds not open ocean.

Neven

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Re: The 2019 melting season
« Reply #6135 on: August 27, 2019, 10:22:39 AM »
MASIE can't be used for annual comparisons, not just because of human interpretation, but also because sources change over time. MASIE is only useful for people who really need to know where the ice edge is.
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philopek

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Re: The 2019 melting season
« Reply #6136 on: August 27, 2019, 10:41:26 AM »
Heat is radiating out from the cloudtops and above so the polar atmosphere is becoming increasingly unstable as we move into September. The models are struggling to capture what's happening more than 3 or 4 days out.

There's still the potential to melt out dispersed ice on the Siberian side of the pole but the horse race is now for the second or third position. It's a good thing that 2012 is looking unbeatable. The fires in Siberia and the Amazon have been depressing enough. We don't need to see any new sea ice records this year to get the message across that the climate is in trouble.

All true while it's perhaps worth to mention that a 3rd place is very hard to reach due to the fact that 2007 and 2016 are almost on par.

If 2nd place is not made, chances are high that it will be 4th rather than 3rd. There is so litte space between current 2nd and 3rd that to hit exactly into that tiny slot would be state of the art by mother nature indeed.
« Last Edit: August 27, 2019, 10:50:13 AM by philopek »

weatherdude88

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Re: The 2019 melting season
« Reply #6137 on: August 27, 2019, 12:40:49 PM »
The 0Z ECMWF looks favorable for ice retention throughout the 10 day forecast period. This period looks to be dominated by weak low pressure over the Canadian Arctic Basin / Central Arctic, with variable weak to moderate strength high pressure throughout the rest of the arctic.

There is the occasional warm air incursion, however you could not ask for a much better forecast for ice retention, especially this time of the year.

The 6Z GFS does show an intense low pressure area developing by day 6. The medium / long range forecast can and will change.









« Last Edit: August 27, 2019, 01:05:23 PM by weatherdude88 »

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Re: The 2019 melting season
« Reply #6138 on: August 27, 2019, 12:46:48 PM »
The five day forecast is looking bad for the ice that is still left around Svalbard, and a "good breeze" will be blowing over the ice on the Siberian side. Now we wait to see if any of those storms turn bad. A new one is popping up on day 5 in the middle of the pack.

(That error is in the data)
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Re: The 2019 melting season
« Reply #6139 on: August 27, 2019, 01:05:04 PM »
The 0Z ECMWF looks favorable for ice retention throughout the 10 day forecast period. This period looks to be dominated by weak low pressure over the Canadian Arctic Basin / Central Arctic, with variable weak to moderate strength high pressure throughout the rest of the arctic.

There is the occasional warm air incursion, however you could not ask for a much better forecast for ice retention, for this time of the year.

The 6Z GFS does show an intense low pressure area developing by day 6. The medium / long range forecast will change.
Yes to all your points. But the weather is unpredictable beyond day 5.

But day 5 is September already
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peterlvmeng

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Re: The 2019 melting season
« Reply #6140 on: August 27, 2019, 01:06:36 PM »
The GFS predicts a storm will influence the north pole from D5-D7. The pressure could be lower than 980hpa. If that happens, the last solid pack will be probably over. To be honest, I do not really care about the extent or area number. If the storm disintegrates all the solid pack, the arctic sea ice is dead in my mind. And I will not focus on the sea ice anymore maybe shifting more concentration on Greenland Icesheet.

philopek

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Re: The 2019 melting season
« Reply #6141 on: August 27, 2019, 01:19:09 PM »
Recent development is highly interesting for a few reasons:

Watching on sat images onc can clearly see that the state of the ice worsened, means, melt is ongoing.

Watching concentration maps, the state of the ice has worsened, hence, verdict remains the same,
melt is ongoing.

In case of doubt, at current temps other than melt-pond over-freeze is barely (not) possible for saline water.

BUT at the same time Extent is stalling and the special, area is stalling as well.

What does it probably mean:

- Extent stall is due to dispersion while most ice staying above the 15% threshold for extenet

- Area is stalling because the freshwater over ice at temps below freezing has frozen

Why do images and concentration show lower numbers despite the above mentioned?

Probably because concentration is indeed lower but still higher than 15%, hence no impact at all on extent numbers, area gain is compensated by the above mentioned melt-pond-freezing.

What can we expect?

If the forecasts hold, we won't see any significant surface melt anymore.

There is a lot of room for compaction given the right weather/wind patterns. in that case we shall see further significant drops and end 2nd. If not we could flat-line with minor drops and ups and downs for weeks and see a steep start into the freezing season because gaps over large areas of dispersed ice will freeze more or less instantly once melt onset has come and we would end probably 4th (3rd would be a point landing between 2016 and 2007)
immediately and that could mean an early low for this year because if large areas freeze in one day, chances that it will melt again are minor and that means one cold night in the right spot where a lot of disperse ice is could do the job to end the melting season.

And yes, i know about bottom melt but can't quantify it and can't assess it's impact, perhaps someone else can.
« Last Edit: August 27, 2019, 01:24:14 PM by philopek »

uniquorn

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Re: The 2019 melting season
« Reply #6142 on: August 27, 2019, 01:21:03 PM »
unihamburg amsr2-uhh comparison of aug26  2012, 2016 and 2019
added scale ;)
« Last Edit: August 27, 2019, 01:56:43 PM by uniquorn »

binntho

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Re: The 2019 melting season
« Reply #6143 on: August 27, 2019, 01:25:18 PM »
unihamburg amsr2-uhh comparison of aug26  2012, 2016 and 2019
Amazingly different!
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peterlvmeng

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Re: The 2019 melting season
« Reply #6144 on: August 27, 2019, 01:29:40 PM »
unihamburg amsr2-uhh comparison of aug26  2012, 2016 and 2019

The solid pack this year is on the edge to completely disappear. A relatively strong storm can easily do that.

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Re: The 2019 melting season
« Reply #6145 on: August 27, 2019, 02:34:00 PM »
unihamburg amsr2-uhh comparison of aug26  2012, 2016 and 2019

The solid pack this year is on the edge to completely disappear. A relatively strong storm can easily do that.

If these images are a true representation of the qualitative state of the ice, it is undeniable that 2012 left a far more compact and intact pack at the end of the season than either 2016 or 2019.  The fact that 2019 appears to be leaving a dispersed and "poor quality" pack across what will likely be a marginally larger extent than 2012 makes this the most damaging melt season of the satellite era.

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Re: The 2019 melting season
« Reply #6146 on: August 27, 2019, 02:34:22 PM »
MASIE can't be used for annual comparisons, not just because of human interpretation, but also because sources change over time. MASIE is only useful for people who really need to know where the ice edge is.
To be fair the website does say it is not to be used for multi year comparisons. That said it sure seems to me other data stalled prematurely.

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Re: The 2019 melting season
« Reply #6147 on: August 27, 2019, 02:59:23 PM »
If these conditions remain, is it wrong to assume that, given an early refreeze, then sea heat will get trapped, and result in poor quality ice all along, which we will pay in the 2020 melt season ?

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Re: The 2019 melting season
« Reply #6148 on: August 27, 2019, 03:57:41 PM »
unihamburg amsr2-uhh comparison of aug26  2012, 2016 and 2019
added scale ;)
It would be good to add a picture of the ice in a "normal" state - like 30 or more years ago or so - to compare how dramatic the situation today really is.
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Freegrass

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Re: The 2019 melting season
« Reply #6149 on: August 27, 2019, 04:16:08 PM »
The ice around Svalbard is already showing some serious damage, and the wind hasn't even started yet.

https://go.nasa.gov/33VIrr0
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