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Messages - oren

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1
Here are the alternative routes:



Here is the current state of play along "Amundsen's Route" (route 4):



"Small vessels" usually take routes 5 or 6 in this day and age.

3
Arctic sea ice / Re: Arctic Image of the Day
« on: June 15, 2019, 06:47:10 AM »
... when we see deep blue on the fast ice on Worldview... is this sometimes what we are looking at???



On worldview, it looks like pic 1
On Sentinel, it looks like this pic 2 (this picture is taken 2 days before, i selected it because of the cloudiness, on 13th it's all blue.)
On RAMMB Slider, in Natural Colour, it looks like pic 3
On RAMMB Slider, in Geo Colour, it looks like pic 4

4
Arctic sea ice / Re: The 2019 melting season
« on: June 15, 2019, 01:32:41 AM »
The low pushing the ice south in the Beaufort, is also pulling the edge of the CAB north, starting to peel it away from the CAA in the past 2 days. The animation shows june 12-14 on Worldview.

Edit: fixed CAB/CAA garbling

5
Antarctica / Re: Halley base shut down and new crack in Brunt shelf
« on: June 14, 2019, 08:01:47 PM »
From Adrian Luckman:  animation of the McDonald Ice Rumples on Brunt Ice Shelf

https://adrianluckman.wordpress.com/2019/06/14/mcdonald-ice-rumples-on-brunt-ice-shelf/


6
Arctic sea ice / Re: "Stupid" Questions :o
« on: June 14, 2019, 07:23:27 PM »
RE:  LeftyLarry
1.   .... "ice comes and goes naturally and man adjusts"
2.  ..."ice been slowly declining since the end of the ice age"   
3.  ...."could a volcanic eruption, bring enough cooling to regrow the lost ice and stop the long term patterns of continued loss"
4. "If all the ice melted and the oceans rose , wouldn’t there still be a huge net gain of habitable land overall?"

    Whether trolling or not, these are questions/assumption many people have, including the U.S. Secretary of State, who recently suggested that people will just move to accomodate a change climate, that climate has always changed, etc.
    What is missing in those perspectives is a sense of scale for time and impacts, along with some basic misunderstandings.

My take on 1-4.
    1.  As others here have noted here and elswhere, it's one thing for a nomadic society of let's say 7,000 humans to move their tents inland in response to millenial rates of change.  Quite another for 7 billion humans with massive infrastructure investments and needs to react to rates of change 10x to 100x faster, thus decadal changes as large as what happend across a 1,000 years in the past. 

     2.  Others here have commented here in more detail.  I'll just add that the "natural" trend has been a gradual cooling since the Holocene peak a few thousand years ago.  Gradual because that cooling was due primarily to natural, = very slow, shift in orbital cycle.  What humans are doing to atmosphere, starting with use of coal as energy source starting ca. 1750, and esp. since 1970 with global increase in fossil fuels, is orders of magnitude more intense and faster than even the most radical climate shifts that led to mass extinctions (90+% of species) in the geologic record.

    3.  Even another Tambora eruption (which caused the "Year without a summer" in New England in 1816) won't protect us from our radical heating of the Earth.  While some climate scientists say the temperature effect is discernible longer than the usually cited 'couple of years', it is temporary nonetheless.  A cooling caused by volcanic emissions into the stratosphere, or a synthetic version through geoengineering, also does nothing to reduce ocean acidification.  Geoengineering to reduce solar energy also introduces major risk of disrupting monsoon and other weather patterns.  "Let's try this, what could go wrong?"  Lots.

    4.  Moving from recently inundated coastlines to newly exposed land formerly under ice caps would bring with it economic and humanitarian destruction of unprecedented scale in the history of human civilization since 4000 B.C.E..  But in addition, just moving the crop belts north isn't going to work.  The temperature bands will move north, but the amount of solar radiation for photosynthesis isn't changing, and the glaciated soil types in central Canada, for example, are not the same as Iowa which used to have 10 feet of top soil in places.  It's going to be tough enough to feed 10 billion people in 2050.  Doing that with degraded ag productivity, which is the consensus projection for global average temperature beyond +1.5-2C (mixed results for lower temp. change) could be impossible. 
      And don't let anybody fool you with the "CO2 fertilization" smoke screen. Increasing CO2 can indeed increase plant growth under controlled conditions where everything else is supplied at optimum (water, fertility, temperature).  Raise CO2 to 450-500ppm in the real world and you won't get any plant growth benefit because those other inputs are not optimized.  Major world food crops are near their thermal maximum now.  Increased temperatures would/will take them over the top of the curve and onto the declining production side even if water supply wasn't an issue.  Moreover, studies find that for the plants that we eat, aka "crops", while they can be grown bigger under higher CO2 with those perfect conditions I talked about above, the density for key nutrients goes down, so a person would have to consume more to get the same amount of nutritional benefit.

    Bottom line - climate disruption is going to kill people.  Lots of them.  The brown and poor people will get hit first, but nobody will escape the consequences of altering the basic life support system of planet Earth.  And by the way, we can't go to Mars.  Think about how many people on Earth it would take to support a colony of a dozen people living inside canisters on Mars.

    So if you love your grandkids (and how could you not) then do everything you can to raise awareness and alarm because this really is a crisis.  It is an unnecessary and avoidable crisis, because we already have the technical capability to produce the energy we need without suicidal continuation of fossil fuel addiction.  The real issue is one of character, long-term wisdom vs. short sighted fear, political will, and mobilization.  Start by refusing to vote for anyone who puts the lives of you, your children, and your grandchildren in mortal danger.

   Sorry for long post.  But you asked and this is the most important issue of human existence.  We have to get this right.  Failure is not an option.

7
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 14, 2019, 06:26:17 PM »
Today's backwards movement as a GIF, for the record.

Last 12 frames from RAMMB Slider. Latest frame 11:23h UTC.

8
Arctic sea ice / Re: Arctic Image of the Day
« on: June 14, 2019, 06:17:10 PM »
This is the largest "melt pond" I have ever seen on the internet. This photo was taken on the NW coast of Greenland. Stunning.

https://twitter.com/RasmusTonboe
@SteffenMalskaer got the difficult task of retrieving our oceanographic moorings and weather station on sea ice in North West Greenland this year. Rapid melt and sea ice with low permeability and few cracks leaves the melt water on top.

9
Surrounding Ice Retreat at Jakobshavn, since this is only a study about how much the ice on the rocks surrounding Jakobshavn Isbræ is affected by the climate changes, the glacier itself is masked, but watch the rocks marked with X, the timespan is only about 2½ year (September 2016 - June 2019), quite dramatic if you ask me?

10
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 14, 2019, 11:11:12 AM »
Animation from DMI's Sentinel-1 ASAR Lincoln Sea images. Jun 04 - Jun 13
Images from http://ocean.dmi.dk/arctic/lincoln.uk.php


11
With all the clear sky we have been seeing recently I couldn't resist putting together an animation of the last month's movements.

12
Arctic sea ice / Re: The 2019 melting season
« on: June 14, 2019, 09:35:35 AM »
The Kolyma River and the Protoka Ularovskaya have both started exuding dark brown waters onto the ice in the East Siberian Sea as can be seen in the last few days.

But today the ice along the entire coast between the two deltas (around the bulbous peninsula) seems to be detached from the shore by a band of brown water. Going in closer in Worldview and it seems to be literally happening between yesterday and today.

13
What does the team make of the latest NWS ice map?

I think the winds made a good run at closing it back up, but fell short, at least so far.  The pack becoming more disperse is allowing the complex currents to reveal themselves.  I'd say a non icebreaker can still safely navigate, but others may have a different opinion on what's considered open.

Contrast boosted for detail

14
Policy and solutions / Re: The Boring Company
« on: June 13, 2019, 06:06:51 AM »
Have some people here not ever been involved in doing something for the first time?  Something somewhat complex.  Generally one starts with some assumptions and refines their ideas as things are tried and better ideas developed.  We didn't get to the Moon by simply building a rocket and going there.  We worked our way there through numerous steps, developing the hardware needed over time.

A few years back Musk proposed the hyperloop, traveling through an almost vacuum in a tube at speeds faster than passenger jets.  He envisioned using an air compressor on the front of the passenger/freight pod to compress what air was in the tube and then blow it out through jets to position the pod equal distance from the tube walls.

There are a few problems with an above ground metal tube.  Acquiring right of way can be difficult and expensive, lots of NIMBY sorts of issues.  A metal tube exposed to sunlight is going to expand and then shrink as it cools.  Which means a bunch of tricky expansion joints.  And JoeBilly could easily shoot some holes in it 'just for fun', or more sinister people could blow up a section.

A solution to those three problems might be to go underground.  In order to make a tunnel water tight it has to be more than capable of maintaining a partial vacuum.  Tunnels are out of sight, out of mind.  And it's not hard to detect someone or something digging its way toward the tunnel long before damage could be inflicted.

But there's the cost of tunneling.  Musk and his crew of merry thinkers went to work and decided that by simply making the tunnels small they became much cheaper per mile.  Then they worked through a number of thing that they could do to drastically lower the cost of tunneling.  Things like almost constantly drilling rather than, on average, ten minutes out of each hour.  Improving the cooling system for the cutter so that it could run at higher speeds.  Finding a way to dispose of the wastes at no cost or even a bit of a profit.

Then bootstrapping.  Building a hyperloop from LA to NYC would require a lot more than pocket change.  The best route is probably building some somewhat short but very fast subway systems in which all rides are 'express', no stops between getting on and arriving at destination.  Build some systems, sell rides, make profits, use profits to build a modest length hyperloop.

The cheapest initial vehicle would be to take an existing battery powered car that could safely travel at 150+ MPH in the tunnel and simply use it.  Later a higher capacity passenger could be built but not until the first system is up, running, and making money.  In fact, it would be very possible to take the Tesla S/X skateboard and bolt a eight or twelve passenger pod on in place of the sedan/SUV body.

Boring has demonstrated that they can drill a tunnel rapidly and at a very attractive cost.  And that is using only a modified used tunneling machine.  Boring has the next two generations of their custom designed tunneling machines in production. 

Boring has demonstrated that they can use an 'off the shelf' Tesla and safely drive their short test tunnel at speeds in excess of 125 MPH.  The first used 'guiding wheels' to keep the car centered in the tunnel but later showed that Tesla's lane keeping software could accurately steer the car.  Yes, the ride was a bit bumpy but, remember, right up front Musk explained that the tunnel driving surface had not been installed.

Boring has demonstrated a prefab elevator that can be quickly installed and moves vehicles from street level to tunnel level rapidly.

Communication between vehicles and between vehicles and 'central command'?  How hard can that be.  Send out position and speed data a few times per second.  If a problem develops issue an "All Stop" to all vehicles behind the vehicle with a problem.  Sensors along the tunnel can serve to backup and verify data from individual cars.

Why would we want this to work?  Imagine leaving your house in a robotaxi, riding a short distance to a Loop spur, changing vehicles, and then going to the airport 20 miles away non-stop at over 150 MPH.  For small money.  Using renewable energy.

Think about not spending a half hour or more each day commuting in bumper to bumper traffic but zipping to work and then back home, giving you an extra hour each day to do something other than commute.

Will it work?  Maybe.  Looks good so far other than finding places to build the first few projects that will be needed for proof of concept.  (Or more proof of concept.)  Boring can bore economically, run cars at high speeds, and move them from surface street to tunnel quickly.  Now the remaining question becomes how inexpensive can they make it.

15
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 13, 2019, 05:59:04 AM »
What I forecasted:
2019 needs to drop an average of 47.2 K km2, to become the lowest on record on June 13th. Will it happen? Today’s drop of 44 K km2 is only 3.2K km2 lower of what it is needed.

I think that 2019 can be the lowest on record on June 13th. Any bets?

What Oren forecasted:
I got this funny feeling 2019 will manage to squeeze between 2012 and 2016 on that date...

Seems that Oren will be right. We will know tomorrow. ;)
Edit: 2019 needs a drop of -91,868 km2 to become the lowest on record tomorrow or needs a drop of -27,385 km2 to become the 3rd. lowest on record.
Hard to get them. Surely, Oren will be right.


[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

June 12th, 2019:
     10,192,504 km2, a drop of -41,133 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).

16
Arctic sea ice / Re: The Rammb Slider Thread
« on: June 13, 2019, 03:52:09 AM »
Greenland, band M8.
Needs click

17
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 12, 2019, 06:17:08 PM »
Animation from DMI's Sentinel-1 ASAR Lincoln Sea images. Jun 02 - Jun 11
Images from http://ocean.dmi.dk/arctic/lincoln.uk.php

I changed the frame interval to 0.5 seconds this time.

The last few frames show ice along the Greenland coast has become locked in place and all the motion is from the north and west. The big floe is moving rapidly toward the entrance now.


18
It's going to look something like this:



This animation is from one the first blog posts on the ASIB, almost 9 years ago to the day.

19
Greenland and Arctic Circle / Re: Greenland 2019 Melt Season
« on: June 12, 2019, 04:30:39 PM »
Oh, boi.

This is Greenland west coast in the M8 band.

That darkening means melting.

20
Nice radar pic came in. I pimped up the contrast.

21
Arctic sea ice / Re: The 2019 melting season
« on: June 12, 2019, 12:10:56 PM »
10.06. vs. 12.06. - ESS

(Click to play)

22
Arctic sea ice / Re: The 2019 melting season
« on: June 12, 2019, 11:02:09 AM »
2012.6.12-2019.6.12 which one is worse

23
Consequences / Re: Hurricane Season 2019
« on: June 11, 2019, 07:56:41 AM »



Percentage increase 1980 to 2016 (as a linear trend) in the number of tropical storms worldwide depending on their strength. Only 95% significant trends are shown. The strongest storms are also increasing the most. Red colors show the hurricane category on the Saffir-Simpson scale. Graph by Kerry Emanuel, MIT. Creative Commons License CC BY-SA 3.0.

Quote
A significant global increase (95% significance level) can be found in all storms with maximum wind speeds from 175 km/h. Storms of 200 km/h and more have doubled in number, and those of 250 km/h and more have tripled. Although some of the trend may be owing to improved observation techniques, this provides some evidence that a global increase in the most intense tropical storms due to global warming is not just predicted by models but already happening.

However, global warming does not only increase the wind speed or frequency of strong storms (which is actually two ways of looking at the same phenomenon, as frequency depends on wind speed).  The average location where the storms are reaching their peak intensity is also slowly migrating poleward (Kossin et al. 2014) and the area where storms occur expands (Benestad 2009, Lucas et al. 2014), which changes patterns of storm risk and increases risk in regions that are historically less threatened by these storms (Kossin et al. 2016).

Most damage caused by tropical storms is not directly caused by the wind, but by water: rain from above, storm surge from the sea. Harvey brought the largest amounts of rain in US history – the probability of such a rain event has increased several times over  recent decades due to global warming (Emanuel 2017; Risser and Wehner, 2017; van Oldenborgh et al., 2017). Not least due to global warming, sea levels are rising at an accelerating rate and storm surges are becoming more dangerous. A recent study (Garner et al. 2017), for example, shows that the return period of a certain storm surge height in New York City will be reduced from 25 years today to 5 years within the next three decades. Therefore, storm surge barriers are the subject of intensive discussion in New York (Rahmstorf 2017).

While there may not yet be a “smoking gun” – a single piece of evidence that removes all doubt – the weight of the evidence suggests that the thirty-year-old prediction of more intense and wetter tropical cyclones is coming to pass. This is a risk that we can no longer afford to ignore.

http://www.realclimate.org/index.php/archives/2018/05/does-global-warming-make-tropical-cyclones-stronger/

My view of KK is as an optimist rather than a straight out denier.
I view my self as a realist though you can call me a pessimist '
Climate change  is a matter if risk. It far better to eer on the side of caution  when so much is at stake.

24
Arctic sea ice / Re: The 2019 melting season
« on: June 11, 2019, 07:55:36 AM »
June 6-10.

It begins.

25
AMSR2 animation the scene.

https://twitter.com/seaice_de/status/1138007405369942016

As always click to play

26
32 hour loop, the frontal passage and associated wind shift is quite evident, it also removes all doubt from my mind that it's clear sailing for a non-icebreaker.



28
Glaciers / Re: Glaciers worldwide decline faster than ever
« on: June 09, 2019, 08:40:32 PM »
In general, the discovery of the most ancient ice in Tibet in 1987 year was later questioned.

https://www.researchgate.net/publication/324453299_Age_of_the_Tibetan_ice_cores

Shallower wells (100–200 meters versus 300 meters) on neighboring glaciers gave an age of less than 100 thousand years.

In this connection, a new well was drilled at Guliya Ice Cap in 2015. And she fully confirmed that this Tibetan ice is the oldest of those found outside of Antarctica.

https://news.osu.edu/researchers-capture-oldest-ice-core-ever-drilled-outside-the-polar-regions/

Quote
December 04,2017

Researchers capture oldest ice core ever drilled outside the polar regions

New Orleans—The oldest ice core ever drilled outside the polar regions may contain ice that formed during the Stone Age—more than 600,000 years ago, long before modern humans appeared.

Researchers from the United States and China are now studying the core—nearly as long as the Empire State Building is tall—to assemble one of the longest-ever records of Earth’s climate history.

What they’ve found so far provides dramatic evidence of a recent and rapid temperature rise at some of the highest, coldest mountain peaks in the world.

At the American Geophysical Union meeting on Thursday, Dec. 14, they report that there has been a persistent increase in both temperature and precipitation in Tibet’s Kunlun Mountains over the last few centuries. The change is most noticeable on the Guliya Ice Cap, where they drilled the latest ice core. In this region, the average temperature has risen 1.5 degrees Celsius (2.7 degrees Fahrenheit) in the last 50 years and the average precipitation has risen by 2.1 inches per year over the past 25 years.

Lonnie Thompson, Distinguished University Professor in the School of Earth Sciences at The Ohio State University and co-leader of the international research team, said that the new data lend support to computer models of projected climate changes.

“The ice cores actually demonstrate that warming is happening, and is already having detrimental effects on Earth’s freshwater ice stores,” Thompson said.

“The water issues created by melting ice on the Third Pole, along with that from the Arctic and Antarctica, have been recognized as important contributors to the rise in global sea level. Continued warming in these regions will result in even more ice melt with the likelihood of catastrophic environmental consequences,” Yao noted.Earth’s largest supply of freshwater ice outside of the Arctic and Antarctica resides in Tibet—a place that was off limits to American glaciologists until 20 years ago, when Ohio State’s Byrd Polar and Climate Research Center (BPCRC) began a collaboration with China’s Institute of Tibetan Plateau Research. There, glaciologist Yao Tandong secured funding for a series of joint expeditions from the Chinese Academy of Sciences.

The name “Third Pole” refers to high mountain glaciers located on the Tibetan Plateau and in the Himalaya, in the Andes in South America, on Kilimanjaro in Africa, and in Papua, Indonesia—all of which have been studied by the Ohio State research team.

Of particular interest to the researchers is a projection from the Intergovernmental Panel on Climate Change that future temperatures on the planet will rise faster at high altitudes than they will at sea level. The warming at sea level is expected to reach 3 degrees Celsius by the year 2100, and possibly double that, or 6 degrees Celsius, at the highest mountain peaks in the low latitudes.

“The stable isotopic records that we’ve obtained from five ice cores drilled across the Third Pole document climate changes over the last 1,000 years, and contribute to a growing body of evidence that environmental conditions on the Third Pole, along with the rest of the world, have changed significantly in the last century,” Thompson said. “Generally, the higher the elevation, the greater the rate of warming that’s taking place.”

Around the world, hundreds of millions of people depend on high-altitude glaciers for their water supply. The Guliya Ice Cap is one of many Tibetan Plateau ice caches that provide fresh water to Central, South, and Southeast Asia.

“There are over 46,000 mountain glaciers in that part of the world, and they are the water source for major rivers,” Thompson said.

In September and October of 2015, the team ventured to Guliya and drilled through the ice cap until they hit bedrock. They recovered five ice cores, one of which is more than 1,000 feet long.

The cores are composed of compressed layers of snow and ice that settled on the western Kunlun Mountains year after year. In each layer, the ice captured chemicals from the air and precipitation during wet and dry seasons. Today, researchers analyze the chemistry of the different layers to measure historical changes in climate.

Based on dating of radioactive elements measured by scientists at the Swiss research center ETH Zurich, the ice at the base of the core may be at least 600,000 years old.

The oldest ice core drilled in the Northern Hemisphere was found in Greenland in 2004 by the North Greenland Ice Core Project and was dated to roughly 120,000 years, while the oldest continuous ice core record recovered on Earth to date is from Antarctica, and extends back 800,000.

Over the next few months, the American and Chinese research teams will analyze the chemistry of the core in detail. They will look for evidence of temperature changes caused by ocean circulation patterns in both the North Atlantic and tropical Pacific Oceans, which drive precipitation in Tibet as well as the Indian monsoons. For instance, one important driver of global temperatures, El Niño, leaves its chemical mark in the snow that falls on tropical glaciers.

Ultimately, researchers hope the work will reveal the linkages that exist between ice loss in tropical mountain glaciers and climate processes elsewhere on the planet. Thompson, Yao, and German ecologist Volker Mosbrugger are co-chairing a Third Pole Environment Program to focus on basic science and policy-relevant issues.

“The more we study the different components of the environment of the Third Pole, the better we understand climate change and its linkages among Earth’s three polar regions,” Yao said.

Collaborators on the project include Ellen Mosley-Thompson, Distinguished University Professor of Geography at Ohio State and Director of BPCRC; Mary E. Davis, Emilie Beaudon, Stacy E. Porter, Ping-Nan Lin, M. Roxana Sierra-Hernández and Donald V. Kenny, all of Ohio State; Guangjian Wu and Baiqing Xu of the Institute of Tibetan Plateau Research; and Ninglian Wang of Northwest University and Keqin Duan of Shaanxi Normal University, both in Xian, China.

Funding for the Guliya project was provided by a grant from the National Science Foundation’s Paleo Perspectives on Climate Change Program, the Strategic Priority Research Program of the Chinese Academy of Sciences, and the Frontier Research of the Chinese Academy of Sciences.


29
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 09, 2019, 06:42:48 PM »
Animation from DMI's Sentinel-1 ASAR Lincoln Sea images. May 31-Jun 08
Images from http://ocean.dmi.dk/arctic/lincoln.uk.php

Something happened to the images on the 6th. I think we're seeing it from a different angle as the satellites move. I missed one partial image on the 6th that got replaced later in the day.

30
Expect a very heavy calving next!!!!!

As promissed:


31
The rest / Re: Unsorted
« on: June 09, 2019, 09:44:42 AM »
I suggest that rather than learn physics from internet fora, one might want to read textbooks ?  and you will need some mathematics for quantized thinking

If you dont have much math, try Griffiths, or try susskind video. You will need some math for both.

If you have some math at undergrad level, but not much, try Feynman (v. III)

If you have the math, try Dirac, or Landau/Liftschitz or many others. In fact if you have the math, you dont need me to recommend.

Dirac is crystal clear and hard as diamond. But worth it. (as is his book on relativistic quantum field theory)

For more modern approaches to quantum field theory, Streater/Wightman, Itzykson/Zuber, Weinberg, or Bogulibov come to mind. 

But to take a larger view, quantum theory is best understood if you understand classical, pre-quantum theory theory. Goldstein and Landau come to mind there. Or what the hell, even Jackson on classical electrodynamics.

But there is no getting away from the math requirement for any of this.

Once you get thru this, Bohm and hidden variables become more understandable.

I will note from your links that Yablon has been pushing his ideas for a while, but very few accept them. Personally i think that Bohm has much more credibility in the physics community.

sidd

32
Arctic sea ice / Re: The 2019 melting season
« on: June 09, 2019, 09:18:41 AM »
June 4-8.

33
    I just read about yet another feedback mechanism I was not previously aware of:
      ' Freshly melted ice ... creates a layer of cold water that protects sea ice above from more melting.   "It isolates the ice from the hot devil water sitting at the bottom waiting to come up" Wagner explains.  Less sea ice means there will be less of that protective cold layer, leading to even more melting. '
https://www.cnn.com/2019/06/08/world/arctic-beneath-ice-intl/index.html

     Which got me thinking it would be useful to have an inventory of all the significant reinforcing ("positive") and suppressive ("negative") feedbacks that affect Arctic sea ice.

    I did not find any forum title where this would fit, but this section seems to be the most closely related topic.  It could require its own thread, similar to the Glossary.

Here is the kind of list I have in mind:

Reinforcing feedbacks:
1. Melted ice creates cold layer that insulates remaining ice from warmer subsurface water.  Less ice to melt reduces this insulating layer.  Which leads to even less insulating cold layer water.

2. Less ice leaves darker ocean water with lower albedo, thus energy from solar radiation is absorbed into water instead of reflected.  Warmer water leads to less ice.

3.  Overall, fractured ice is more mobile and thus more susceptible to being exported via Fram Strait or Nares Strait.  There is chance of an ice bridge to block export via Nares Strait with fractured, reduced ice cover.  Increased export results in less multi-year thick ice, and more mobile young ice the next year.

4.  Fractured or thin sea ice floes have more surface area per unit volume and therefore melt at lower temperatures than thicker ice, or larger ice floes.  This leads to less surviving ice the summer to become thicker multi-year ice.

5.  Fractured vs. contiguous ice allows more wave action that interferes with freezing of ice and allows wave action to break ice into smaller pieces less resistant to melt.  Resulting in more fracturing of the remaining ice and even more wave action.

6.  Albedo reduction by replacing ice with dark water leads to warmer water and more energy in the Arctic Ocean system.  That in turn increases frequency, intensity, or both, of cyclones causing wave action that break up ice. Which reduces albedo even further.

7.  Weakening of the Polar Cell results in more frequent occurrence of Arctic Dipole, that increases export of ice out of the Arctic, which lowers Arctic sea ice, which leads to warm Arctic Ocean water, which leads to further weakening of the Polar Cell.  (whew, that's a long chain)

8.  Loss of ice cover weakens the polar cell which in turn allows more incursion of of warm moist air masses from the south into the Arctic, which leads to more weakening of the polar cell.

9.  Weakening of the polar cell allows more cyclonic systems to move into the Arctic.  Those cyclones disrupt the Arctic sea ice, and in doing so further weaken the polar cell.

10.  Younger, thinner ice has higher salt content and thus lower melt temperature.  Therefore it has less chance of surviving the summer melt to become more resistant, thicker multi-year ice.

11.  Reduced snow cover allows earlier spring warm up of Arctic land mass, which results in warmer air flowing onto the Arctic Ocean. This warms the system as a whole, leading to reduced snow cover and earlier snow loss the following year. 

12.  More open ocean leads to higher humidity and more extensive or thicker cloud cover over the Arctic Ocean in the fall and winter.  More extensive or thicker cloud cover in fall and winter reduces heat loss thus reduces winter refreezing.

13.  Earlier spring warm up of Arctic land mass, results in increased permafrost and land ice thaw, resulting in earlier and more melt water flowing from land into the Arctic Ocean. The meltwater warms the Arctic Ocean and reduces Arctic sea ice.  Which leads to more open water with lower albedo to absorb solar radiation in the summer, increasing summer heat content of the system  More open water allows this heat to escape to moderate winter air temperatures and earlier spring warm up.

14.  Reduction of Arctic sea ice allows increased flow of warmer Pacific or Atlantic water into the Arctic, leading to further decline of Arctic sea ice, leading to more Pacification and Atlantification of the Arctic Ocean.

***
Compensatory or Suppressive feedbacks:
1.  Ice cover insulates the Arctic Ocean in winter.  With less sea ice cover there is faster energy loss and winter cooling, and thus faster winter ice increase after a lower September minimum extent.

2.  Thin ice grows much faster than thick ice.  Thus faster winter ice increase compensates for thinner ice after a strong melt season. 

3.  More open ocean leads to higher humidity and more extensive or thicker cloud cover over the Arctic Ocean in the summer.  More extensive or thicker cloud cover in summer reflects more solar radiation and thus reduces summer ice melt.

*****************************

     My wording is no doubt less than perfect for many of these.  Some may be just plain wrong.  Some I just made up!  Maybe I should just find a good book or review article with such a list.  Any suggestions?

   If you think a proposed feedback is incorrect or wrongly stated, it would helpful to have that noted.  But I'm not looking to start multiple debates about which feedbacks are most important. 

      I don't get a commission for each new proposed feedback, so there's no need to get heated.  The planet is hot enough as it is.  These are just suggested entries.  There must be suppressive feedbacks missing from the list.

   I just thought a list would be interesting because I keep finding out about feedbacks I had not previously been aware of. 





34
Arctic sea ice / Re: Arctic Image of the Day
« on: June 08, 2019, 06:56:39 PM »
04.06. vs 08.06. (in the west of Lena)

(Click to play)

35
Arctic sea ice / Re: The 2019 melting season
« on: June 08, 2019, 09:34:27 AM »
Imo it's premature to be surprised about the small fraction of ice surface showing melt ponds.

Attached is a gif of SMOS microwave images for each year from 2010 through 2019.

Specifically, the images are yyyy0607_hvnorth_rfi_l1c.png, where yyyy is the year, obtained from https://seaice.uni-bremen.de/data/smos/png/.

These images are sensitive to melt ponds.
IGNORE THE COLOR LEGEND'S NUMERICAL SCALE & LABEL (the color order progression should be valid though) - DURING THE MELT SEASON THESE ARE NOT LEGITIMATE THICKNESS MEASUREMENTS. Instead, my understanding is that any color other than beige indicates ice that is:
a) thin, ~<50 cm; &/or
b) has concentration well below 100%; &/or
c) has surface liquid water.
In particular, colours other than beige in the ice pack interior are likely to indicate the presence of surface water.

& it is seen that only 4 of the 10 years have extensive melt ponding in the Arctic Basin on 7 June: 2012, 15, 16, and 18.

All of 2010, 11, 13, 14, 17, and now 2019, don't have extensive melt ponding by 7 June.

So the comparisons above with 2012 are not particularly surprising, given that 2012 is one of the 4 years in the data record that has extensive melt ponding on 7 June, while 5 of the 9 previous years on record are similar to 2019 in not displaying extensive melt ponds by 7 June.


P.S. Given the weather forecast, I expect SMOS to show extensive melt ponding, especially on the Russian side, within the next few days.

36
Arctic sea ice / Re: The 2019 melting season
« on: June 07, 2019, 11:23:34 PM »
Here is almost all of the near real-time evidence we have for melting momentum. I could also post SMOS maps, or even Uni Bremen SIC maps, but that's just too much work.

37
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 07, 2019, 09:07:28 AM »
Meltponding in Kane Basin.

38
Arctic sea ice / Re: The 2019 melting season
« on: June 07, 2019, 02:08:20 AM »
    A friend and colleague who is a PhD climate scientist, and whose work is regularly cited in this forum ... (but I'll leave his name out of it, even though Sean said it was OK to cite him... ooops)

    ....and who has watched Arctic weather for many years, brought the subject up at the end of a day-job phone conversation earlier this week.  He said it's hair raising, that he's never seen anything like what (as of Tue. June 4), was forecast for the next 10 days, esp. the latter part of that forecast as we head into mid-June.  One that I was not previously aware of was the amount of precipitable water in the air masses flowing into the Arctic.  e.g. https://climatereanalyzer.org/wx/fcst/#gfs.arc-lea.pwtr

  And the story is not limited to the Arctic sea ice.

    One striking example as he walked me through a hall of horrors of forecast images was an image of the infamous ~97% Greenland surface-melt day (edit: days in July & August 2012.  The one that was so bizarre that NASA seriously thought the satellite sensor must have gone bad because such a reading was unprecedented and unfathomable.  (And which my friend on the phone said GFS foresaw at least a week in advance, just to defend the underloved GFS a bit.  BTW - GFS is getting the FV3 upgrade June 24!). 

     Then he took me to the 10-day 10th day Greenland surface temp image for this JUNE   And while not covering the almost the entire GIS as happened in the 2012 blasts, the 2019 forecast image was for a 10-day average, not a single day, and the 2019 image was for mid-June, not July or August.

    Another striking image was the projected very early 2019 timing for loss of ice/snow cover north of Greenland.

    While I'm a long time climate hawk and ASIB watcher, not being a climate scientist and being only a recent ASIF lurker with a post count even smaller then Trump's tiny little extremities (I'm talking about his hands, jeesh, get your mind out of the gutter!), it's been difficult for me to interpret the "contextual significance" for all the recent hubub about the 2019 melt season. 

     So for others of you watching the discussion from that perspective, the point of this post is that a PhD climate scientist with expertise and experience in Arctic weather (while acknowledging that forecasts can change, that June is not the whole summer, and that the Arctic is fickle) is having his own "Holy Cow" moments this week, to put it politely.  Stay tuned.  And vote climate. 

39
Arctic sea ice / Re: The 2019 melting season
« on: June 06, 2019, 11:35:39 PM »
Here is a tentative ranking of subjective whiteness from whitest to bluest/greenest for June 5th from 2000 to 2019, based on https://go.nasa.gov/2WWvSva these Worldview settings.

1st (lightest): 2004
2nd: 2000
3rd: 2003
4th: 2009
5th: 2006
6th: 2018
7th: 2002
8th: 2008
9th: 2014
10th: 2013
11th: 2001
12th: 2017
13th: 2010
14th: 2005
15th: 2015
16th: 2011
17th: 2019
18th: 2007
19th: 2016
20th (darkest): 2012


40
Arctic sea ice / Re: Do we make too much of 2012 ?
« on: June 06, 2019, 05:53:04 PM »
I don't think that we make too much of 2012, because 2016 looks much worse. And 2012 looks worse than 2007. Neither 07 nor 12 was a one-time event - it's a trend.
True, 2012 had smaller extent than 2016, but if I look at the Uni-Bremen ice concentration maps, I can see, that we had much less "solid" ice in 16 than 12 (sea ice concentration maps on Sep 1, purple is 100% ice concentration, 16 above, 12 below):

41
Arctic sea ice / Re: The 2019 melting season
« on: June 06, 2019, 08:05:51 AM »
I don't have a lot of time right now to talk about the weather up there but all I can say is right now looking at the all the models and what we've seen so far and they huge albedo drop taking place you can see on the satellite over most of the Arctic.

This year is starting to set up to be an epic f****** melt year.

I'm talking almost the entire ice sheet gone blowing the f****** doors off of 2012 there's no guarantees.

Just stay tuned and be prepared to be blown the f*** away.

I'm sure it won't happen but look at that f****** ridging around Greenland into northern Canada this is the kind of setup we need to see a big f****** bosses and this is trying to set up a right near the solstice oh my God talk about weather p***.


42
Arctic sea ice / Re: The 2019 melting season
« on: June 05, 2019, 11:37:28 PM »
Sentinel images of Lena water spreading out over ice, over 3 days.

Click to animate

43
Arctic sea ice / Re: SMOS
« on: June 05, 2019, 05:06:07 PM »
The 2019 melt season is now well underway.  Like last year, I run a pixel counting algorithm on the SMOS images. 

In summer SMOS is sensitive to surface melting.  The beige pixels in the SMOS images would correspond to sea ice with a dry surface (without melt ponds).  During June, the number of beige pixels in the images tends to decrease fast as surface melting becomes more widespread in the Arctic Ocean.

Based on this metric, surface melting in 2019 has been mediocre in the last few weeks (slightly weaker than the 2010s average).  But it's still early in the season and a lot can happen.



https://www.dropbox.com/s/fl2xs6aeop3ioen/SMOS_beige_pixels.png

To keep this graph up-to-date, I uploaded it on dropbox.com and it will be updated every day with the latest data.

45
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: June 05, 2019, 04:27:42 AM »
This is very likely the same cherry as "No warming since 1998!" or the hiatus, but because the next state change hasn't happened I will do it.  All that needs to happen for this line to come true is that in a warming world Arctic ice doesn't melt faster. It could happen, but I wouldn't bet the fate of our civilization on it.

The state change can be appreciated on attachment one. From 2000-2012 the Loss to Max ratio increased almost monotonically, then after 2012 the Loss to Max Ratio flattens. I drew a 6 year moving average that shows the behavior I'm attempting to show.

It seems that in the "High Arctic" the state change began in 2012. Thus I'm ignoring all previous years to 2012 and I'm drawing the line using only the years after 2012. I'll update after the next minimum is reached.

(R2 value provided.)

46
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 04, 2019, 11:05:15 PM »
Animation from DMI's Sentinel-1 ASAR Lincoln Sea images. May 27-Jun 04
Images from http://ocean.dmi.dk/arctic/lincoln.uk.php

47
Policy and solutions / Re: Coal
« on: June 04, 2019, 04:03:55 PM »
Just to add to what b_lumenkraft says, the aim is to reduce CO2 emissions, and the emission of other pollutants. Reducing the amount of natural gas and coal burned does exactly that. And adding renewables leads to a reduction in gas and coal-fired generation – that's what the figures show. They also clearly show that overall, coal is not being replaced by gas, it is being replaced by renewables.

If the end state involves having some gas-fired power stations in reserve that are needed very occasionally, that's no great tragedy. Emissions follow power generation, not the number of power stations. For the moment, we don't need to worry about the end state - plenty more renewables can be added to replace even more of the coal- and gas-fired generation. Let's try to get to 80% clean power (renewables+nuclear) - by then the technology will undoubtedly make it easier to replace the remaining 20% than it is today.

48
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: June 03, 2019, 09:13:24 PM »
Inspired by Gerontocrat's insightful graphs, I decided to see what the lines look like for the "High Seas"  in PIOMAS.

Edit: True to form the previously posted graphs only included 6 seas ( I mistakenly excluded the Kara sea). Then calamity happened and I lost all the formulas. Got to do it again... My apologies.

Edit: Fixed. the 7 seas are included.

49
Arctic sea ice / Re: The 2019 melting season
« on: June 03, 2019, 04:30:30 PM »
 The Beaufort gyre ice destroyer is up and running, the bottom melt caused by all that +1 degree water is telling already. If the high pressure holds the Beaufort could be at 2-3 degrees in a week. I just hope we don't get a replay of 2012 when you can see big old ice floes disintegrate in days after being swept into water at 8 degrees.

 Below is a picture comparison between May 27th and June 2nd. I wonder just how much bottom melt there was in this de compacted pack last month?

(edit)

 I'll answer my own question here https://cryospherecomputing.tk/SIT.html and it's worse than I expected.


50
Consequences / Re: Climate change, the ocean, agriculture, and FOOD
« on: June 03, 2019, 06:42:08 AM »
Food prices in REAL terms (which means adjusted for inflation) are where they were in the 60s and 70s, and only 50% higher than at the multidecade lows around 2000, when oil prices were only a third of today's. That is quite amazing in itself since oil prices drive food prices very much.

Indeed, it's impressive that so far food prices have been as steady as they have in spite of rising oil prices, freshwater depletion & contamination, fish stock depletion, 80m more mouths to feed each year, desertification, general climate change-related disruption etc.

So far, of course, being a key point to note. I'm not sure how much longer this can go on.

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