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Re: Arctic Sea Ice 2017 Pt. 1

Unread postPosted: Sun 03 Sep 2017, 11:43:05
by vtsnowedin

Re: Arctic Sea Ice 2017 Pt. 1

Unread postPosted: Wed 06 Sep 2017, 11:33:01
by vox_mundi
Unraveling a Major Cause of Sea Ice Retreat in the Arctic Ocean

Recently, ice-ocean "albedo feedback" has emerged as a key cause for sea ice melt. The feedback is generated by a large difference in albedo – a measure of light reflectivity – between open water and ice surfaces. As dark ocean surfaces absorb more light than white ice surfaces, solar heat input through the open water melts sea ice, increasing both open water areas and heat input and thus accelerating sea ice melt.

Analyzing the data from 1979 to 2014, the researchers found the solar heat input through open water surfaces correlated well with ice melt volume, suggesting heat input is a major causative factor of melting ice. This was particularly obvious after 2000, when there were considerable reductions in sea ice.

Image
Accumulated heat input through open water surfaces in the surveyed area from May to August (red line) correlated well with interannual variations in ice melt volume (black line) between 1979 and 2014. Sea ice melt volume is converted to the heat input required for ice melt. Blue crosses and red circles indicate values before and after 2000, respectively.

In addition, divergent ice motion in the early melt season can be a trigger of ice melt acceleration through ice-ocean albedo feedback. After the 2000s, such relationship has likely become stronger, suggested by a much higher regression coefficient than that prior to 2000.

These results also suggest that ice motion in the early melt season may possess predictive skill in seasonal sea ice forecasts in this sector of the Arctic Ocean.

Image
Schematic of ice and heat budgets during seasonal ice retreat. Divergent ice motion in the early melt season induces a small reduction in ice concentration (upper panel). A key finding is that although the direct contribution of doubled divergent ice motion after 2000 to the ice concentration reduction is small, this trigger accelerates ice melt through the enhanced solar heat input over the open water fraction (ice-ocean albedo feedback) until the end of August (lower panel).

Haruhiko Kashiwase et al. Evidence for Ice-Ocean Albedo Feedback in the Arctic Ocean Shifting To a Seasonal Ice Zone, Scientific Reports (2017)

Good news

Unread postPosted: Wed 13 Sep 2017, 05:35:35
by Whitefang
Good news from up North:

http://neven1.typepad.com/

It seems my prayers from May have been heard:

There's nothing else to do but hope that PIOMAS has it completely wrong, or else pray for lots of cold and cloudy weather in the Arctic this summer.

Well, the weather did its thing and produced one of the biggest turnarounds in the Arctic I have seen so far. I mean, in 2013 the ice managed to return from the brink of death, so to say, but at least the winter preceding it had been very cold. This year the melting season started with a record low volume after an incredibly mild winter.

One consequence of that mild winter, however, was lots of snowfall on the ice and adjacent land masses (see here). This snow likely managed to reflect some of the sunny weather that creates what I call melting momentum during May and June. So, with snow melting out late and not much melting momentum to speak of (yet again), it all came down to what kind of weather we'd be seeing during July and August. Cue low pressure.

Re: Arctic Sea Ice 2017 Pt. 1

Unread postPosted: Thu 14 Sep 2017, 11:57:28
by Cid_Yama
With the coolest and least eventful, storm wise, summer we have had, we still are among the lowest on area and extent. But volume is still declining. Volume is 70% below 1979. Most of that lost after 2003.

Area and extent dominated by spreading slush does not bode well. Remember what those numbers represent. >15% sea ice. Set that at >50% and it tells a whole different story.

There is nothing hopeful going on, we are losing the ice rapidly. We just managed to dodge the bullet this year, area and extent wise. But not volume wise.

Re: Arctic Sea Ice 2017 Pt. 1

Unread postPosted: Fri 15 Sep 2017, 07:58:15
by Whitefang
Using piomas for volume, now at around 5000 cubic km, min level of 2011 and 2015. Not at record low of 2012, more or less 4000 ckm.
Still 7000 ckm under the mean of 1979/2016, which mean volume is already far below normal for having reached a tipping point last decade.
Will probably make for third lowest on record.

http://neven1.typepad.com/.a/6a0133f03a ... 128970c-pi

Re: Arctic Sea Ice 2017 Pt. 1

Unread postPosted: Fri 15 Sep 2017, 10:23:43
by Cid_Yama
Average Arctic sea ice volume through Aug 2017 was 5.5 km3 a bit above the record of 2012 (5.0 km3). August 2017 volume was 70% below the maximum August ice volume in 1979, 56% below the 1979-2016 mean, and about 0.4 standard deviations below the long term trend line. While 2017 started well below prior years and remained so through May, ice loss during June through August was less than previous years. This is shown in Fig 8 which compares daily ice volume anomalies for several recent years (base period 1979-2016). The difference between 2012 (the previous record) is notable. While 2017 started out with much lower sea ice volume, 2012 had a much more rapid sea ice loss through May and June. Both 2012 and 2017 have very similar anomaly progression through July. August 2017 by comparison was a month of reprieve relative to 2012.

link

The chart you are referring to only shows through mid-August. You can see a larger version by clicking on it at the link. At that time, 2017 had just allowed 2011 to catch up and was tied for second behind 2012. (that line you mistook for 2015 is actually 2010, 2015 is up between 2014 and 2013. 2016 is hidden behind the 2010 line in mid August, and achieved lowest in mid September.) 2013-2014 had seen an increase in volume from 2012, but we have since lost that volume again, rapidly since 2014, with a huge drop between 2015 and 2016.

Here is a short 3D representation that really puts it across.

https://www.youtube.com/watch?v=9NP0L1PG9ag

No hope but buying time before the inevitable decline

Unread postPosted: Sat 16 Sep 2017, 06:42:28
by Whitefang
Ok Cid, thanks for clearing that up.

I agree there is no hope for sea ice up North but we are given an extra year of a near normal winter ice cover...I hope so as what we, everybody needs is time.
No hope long term for any natural ice/permafrost/snowcover on Earth I suppose, a direct result of abruptly flipping into a hothouse instead of swinging between glacial times.
Mt Vinson and that high one, Denali might be the last place sometime in the future to find glaciers.
I bet those glaciers in Africa are already toast, Kilimanjaro.....
Way, way of topic, 70 degrees of wonderful Earth.

Here you go, race against time:

https://www.theguardian.com/environment ... anda-congo

Ptolemy thought they were the source of the Nile and called them the Mountains of the Moon because of the perpetual mists that covered them; Stanley claimed to be the first non-African to see their icecap; and the many thousands of subsistence farmers who today live on the slopes of the fabled Rwenzori mountains in Uganda and the Democratic Republic of the Congo fear that warming temperatures are devastating their harvests.

While 20,000 people a year scale Mount Kilimanjaro in Tanzania, just a handful of trekkers tackle the lower, 5,100m Rwenzori summits and witness the spectacular plant forms that grow in some of the wettest conditions on Earth. The result is that little is known about the condition of the many tropical glaciers that descend off the three peaks of mounts Baker, Speke and Africa's third highest peak, Mount Stanley.

But last month, a micro-expedition led by London-based Danish photographer Klaus Thymann returned from Uganda with the best evidence yet that the 43 glaciers found and named in 1906 are still mostly there, but are in dire condition and can be expected to disappear in a decade or two.


https://www.livescience.com/41930-kilim ... nking.html

SAN FRANCISCO — Kilimanjaro's shrinking northern glaciers, thought to be 10,000 years old, could disappear by 2030, researchers said here yesterday (Dec. 12) at the annual meeting of the American Geophysical Union.
The entire northern ice field, which holds most of Kilimanjaro's remaining glacial ice, lost more than 140 million cubic feet (4 million cubic meters) of ice in the past 13 years, said Pascal Sirguey, a research scientist at the University of Otago in New Zealand. That's a cube measuring roughly 520 feet (158 m) on each side.
The loss in volume is approximately 29 percent since 2000, while the total surface area lost is 32 percent, Sirguey said. Last year, the ice field split in two, revealing ancient lava that may not have seen the sun for millennia. [Video: Kilimanjaro's Shrinking Glaciers]


Looks like they are still there but not for long, and those people studying the glaciers are not likely to have taken into account the recent stage of abrupt CC.

Re: Arctic Sea Ice 2017 Pt. 1

Unread postPosted: Thu 21 Sep 2017, 13:22:59
by dolanbaker
Move along now, nothing to see here. Looks like the minimum extent was nothing to write home about, no catastrophic collapse in area that many here predicted.

Re: Arctic Sea Ice 2017 Pt. 1

Unread postPosted: Thu 21 Sep 2017, 13:28:35
by dolanbaker
onlooker wrote:You deniers are really stretching your denial here. Anyone with a working brain can see something very anomalous is happening in the Arctic now. Like being on the verge of a relatively ice free Arctic sea. Duh.

Looked no worse than it has been for the past few years, a fairly unremarkable minimum when compared to some of the recent lows.

Re: Arctic Sea Ice 2017 Pt. 1

Unread postPosted: Fri 22 Sep 2017, 00:16:00
by Cid_Yama
Here. You obviously missed this.

https://www.youtube.com/watch?v=9NP0L1PG9ag

Re: Arctic Sea Ice 2017 Pt. 1

Unread postPosted: Fri 22 Sep 2017, 01:55:44
by dolanbaker
That's last years news.