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Author Topic: Latest PIOMAS update (August 2019)  (Read 1003848 times)

Yuha

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Re: Latest PIOMAS update (August 2019)
« Reply #3000 on: August 04, 2019, 03:40:37 PM »
Wipneus, the thickness map in your post #2992 is last year's map not this year's.

FishOutofWater

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Re: Latest PIOMAS update (August 2019)
« Reply #3001 on: August 04, 2019, 04:02:50 PM »
This year the transpolar drift has been strong and Fram export has been high compared to the last decade. The lack of Fram export in July has become the new normal as warm salty Atlantic water pushes back into the ice pack melting ice out before it reaches the Fram. There's also a summer seasonal tendency for winds that don't favor Fram export. That doesn't mean that export hasn't been high this year. The relatively high ice thickness on the Atlantic side of the basin is evidence of the strong transpolar drift that has affected the ice this year.

Wipneus

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Re: Latest PIOMAS update (August 2019)
« Reply #3002 on: August 04, 2019, 07:43:34 PM »
Wipneus, the thickness map in your post #2992 is last year's map not this year's.

Fixed, thanks for the notice.

oren

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Re: Latest PIOMAS update (August 2019)
« Reply #3003 on: August 05, 2019, 07:25:30 AM »
Looking at the regional volume charts, there is a striking difference between the ESS and the Chukchi which have crashed far ahead of 2012, and the Laptev and the Beaufort which have managed to stabilize temporarily. The difference of course is the export from the CAB that has been feeding the latter seas.
Comparing with 2012, we know in hindsight that the ESS and Chukchi did go to zero eventually. OTOH, we don't know yet if the Laptev and Beaufort will manage to zero in 2019. My best-effort estimate does call for both to melt out by the date of the minimum.

oren

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Re: Latest PIOMAS update (August 2019)
« Reply #3004 on: August 05, 2019, 08:13:04 AM »
Next come the question marks, where no amount of eyeballing can generate a reliable prediction. The Greenland Sea, where the halt of export has resulted immediately in a mini-crash, should reach the minimum with lower volume than 2012, but not much more can be said.
The CAA is consistently lagging 2012, and it's hard to say whether it will continue melting (e.g. 2010 trajectory) and possibly reach the 0.05-0.1 level later, or taper off into the distance a la 2016 or 2017. Most low years taper off from here, but this year is quite warm and still has the potential. My gut says partial taper.
In the CAB 2019 still maintains a healthy lead, some of it thanks to the above-mentioned export, and some thanks to the "crack" (of course both phenomena are related). However, in hindsight we know that 2012 had a mini-crash a week from now, thus giving it a serious advantage. This year could continue racing 2012 to the bottom, or could taper off following many other respectable years. My gut says race 2012 thanks to heavy preconditioning but probably finish 2nd, barring a GAC. My gut also says there should be a GAC, so...
Looking at the sum total of all regions participating in the minimum, the situation is similar, healthy lead but smaller than the mini-crash coming up in 2012, so same gut feeling: probable 2nd, but race not finished.

uniquorn

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Re: Latest PIOMAS update (August 2019)
« Reply #3005 on: August 06, 2019, 12:20:37 PM »
Piomas percentage remaining from maximum for CAB

FishOutofWater

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Re: Latest PIOMAS update (August 2019)
« Reply #3006 on: August 06, 2019, 03:42:08 PM »
That highly anomalous steepening of the volume curve in mid-August 2012 is best explained, in my opinion, by Ekman pumping of heat from the Atlantic water layer into the surface ocean. Normal storms can't do this because they don't persist long enough to break up the strong density inversions. The GAC lasted ten days and was very intense at its peak. It was strong and persistent enough to break down the layering in a large volume of the Arctic ocean.

The buoy profiles were stunning. Ekman pumping by persistent high pressure areas has caused multiple episodes of upwelling along the continental shelf in the Beaufort sea, but I'm not aware of any storm other than the GAC causing a upwelling of mid-ocean water in the central Arctic ocean. There was a very large amount of energy involved in the rapid melting of ice in mid-August 2012. Because there were not large amounts of heat advected by the atmosphere, it must have come from the ocean.

This melting season atmospheric heat advection may be larger than it was in 2012, but so far storms are not persisting like the GAC, so we should perhaps expect less bottom melt from ocean heat than took place in August 2012. However, sea surface temperatures in the Arctic are very high this summer so there is a lot of ocean heat in the upper layers. Moreover, strong atmospheric heat advection has been persisting in the Arctic for months. We are going to get a chance to compare the effects of different processes on the melt minimum by comparing 2012 and 2019. The sea ice volume curves are a most important aspect of that comparison because they are a function of system enthalpy (heat).

SteveMDFP

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Re: Latest PIOMAS update (August 2019)
« Reply #3007 on: August 06, 2019, 03:52:11 PM »

...
The buoy profiles were stunning. Ekman pumping by persistent high pressure areas has caused multiple episodes of upwelling along the continental shelf in the Beaufort sea, but I'm not aware of any storm other than the GAC causing a upwelling of mid-ocean water in the central Arctic ocean.  ...

This is an eloquent interpretation and elegant synthesis of disparate data into a summary.
Naturally, I agree.  ;-)

peterlvmeng

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Re: Latest PIOMAS update (August 2019)
« Reply #3008 on: August 06, 2019, 03:54:02 PM »
That highly anomalous steepening of the volume curve in mid-August 2012 is best explained, in my opinion, by Ekman pumping of heat from the Atlantic water layer into the surface ocean. Normal storms can't do this because they don't persist long enough to break up the strong density inversions. The GAC lasted ten days and was very intense at its peak. It was strong and persistent enough to break down the layering in a large volume of the Arctic ocean.

The buoy profiles were stunning. Ekman pumping by persistent high pressure areas has caused multiple episodes of upwelling along the continental shelf in the Beaufort sea, but I'm not aware of any storm other than the GAC causing a upwelling of mid-ocean water in the central Arctic ocean. There was a very large amount of energy involved in the rapid melting of ice in mid-August 2012. Because there were not large amounts of heat advected by the atmosphere, it must have come from the ocean.

This melting season atmospheric heat advection may be larger than it was in 2012, but so far storms are not persisting like the GAC, so we should perhaps expect less bottom melt from ocean heat than took place in August 2012. However, sea surface temperatures in the Arctic are very high this summer so there is a lot of ocean heat in the upper layers. Moreover, strong atmospheric heat advection has been persisting in the Arctic for months. We are going to get a chance to compare the effects of different processes on the melt minimum by comparing 2012 and 2019. The sea ice volume curves are a most important aspect of that comparison because they are a function of system enthalpy (heat).

I agree. The central arctic ice pack is solid even after GAC. This year the central ice pack will not be as solid as 2012, maybe even weaker than 2016.

Sterks

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Re: Latest PIOMAS update (August 2019)
« Reply #3009 on: August 06, 2019, 04:16:19 PM »

...
The buoy profiles were stunning. Ekman pumping by persistent high pressure areas has caused multiple episodes of upwelling along the continental shelf in the Beaufort sea, but I'm not aware of any storm other than the GAC causing a upwelling of mid-ocean water in the central Arctic ocean.  ...

This is an eloquent interpretation and elegant synthesis of disparate data into a summary.
Naturally, I agree.  ;-)
Yes, good summary.

be cause

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Re: Latest PIOMAS update (August 2019)
« Reply #3010 on: August 06, 2019, 04:34:43 PM »
https://pbs.twimg.com/media/EBNXh7cWwAAlPJ7.jpg:large  ... the Arctic death spiral updated .. b.c.

 ps.  borrowed from Eric Holthaus on twitter .. sorry you have to click to see ..
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

philopek

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Re: Latest PIOMAS update (August 2019)
« Reply #3011 on: August 06, 2019, 05:24:11 PM »
Same w.o. click:

Hope it's ok, else I gonna remove it ;)

be cause

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Re: Latest PIOMAS update (August 2019)
« Reply #3012 on: August 06, 2019, 06:45:05 PM »
cheers .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Neven

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Re: Latest PIOMAS update (August 2019)
« Reply #3013 on: August 07, 2019, 11:30:22 PM »
Il faut comparer, comparer, comparer, et cultiver notre jardin

Archimid

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Re: Latest PIOMAS update (August 2019)
« Reply #3014 on: August 11, 2019, 11:21:49 PM »
Correlation Coefficients between pre and post day 212

Piomas: -0.32344182
High Arctic: -0.227528106
Arctic Basin: 0.042631957
CAB: 0.724407856


Graphs attached.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.