1
Arctic sea ice / Re: River ice and Discharge
« on: June 03, 2020, 10:44:31 PM »
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2
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: June 03, 2020, 09:35:50 PM »2012 was really not such a huge outlier in terms of volume. 2010 was a big drop and 2011 was not too much different than 2012 in volume.Maybe there is a slowdown of sorts, but Chris Reynolds and his Slow Transition predicted it very well already in 2013, while I think DHACSOO does not explain the slowdown well - even though it has more data at its disposal.
From 1979 to 2011 volume went from 17k km3 to 4k km3. 8 years later we are still at the 4k km3 level and this year is not in a good position to break a new record either. From 2002-2012, the record was broken more years than not. Now we have seven years with no record.
If that is not evidence of things slowing down, what would be the criteria to demonstrate that things are slowing down? This is no parallel flat period in the 40 year volume history.
Once MYI has been turned mostly to FYI, it is much harder to continue to drop volume at the same rate. However, the 2016-2017 freezing season showed it was not that difficult after all. Had the 2017 melting season not been mediocre, a new volume record would have been made easily.
3
Arctic sea ice / Re: River ice and Discharge
« on: June 03, 2020, 09:27:27 PM »
For some reason the gif is not playing for me.
4
Arctic sea ice / Re: "Stupid" Questions :o
« on: June 03, 2020, 09:25:19 PM »
Adding more guesses, it could depend on local obstructions from the south, such as tall trees near the water or some hill. Since the sun is quite low in the spring, any obstructions can delay melt-out. In addition, incoming water in the spring could make a difference, so it would depend on local snow cover and vegetation. Still, lake depth should be the biggest variable.
5
Arctic sea ice / Re: The 2020 melting season
« on: June 03, 2020, 02:08:54 PM »A lurker here. However, I feel the need to write so that people could perhaps clarify some things here. People have been writing that due to lack of aerosols now there was supposed to be constant sunlight in Arctic. But now it turns out it's cloudy there? People here on the forum have been hyped up that there is going to be massive melt in Arctic, but nothing was happening in late May. (of course, a long way still to go this season)Welcome Jens!
I just hope people would clarify what is the actual situation in Arctic. Is it sunny or cloudy then? Is the shutdown of economy and lack of aerosols actually having an effect or not? In mid-May people were writing that impressive weather events at that moment were going to kickstart an impressive melting campaign. So what is the outcome then?
People also write about "preconditioning/meltponding" of ice, and it is supposed to be highly favourable for a good melt season this year. How much time would it take to actually materialize in an actual melt? Or perhaps this 'preconditioning' never truly materializes and we end up with a whimper of a melt season? (which in my view would be anything outside top3 in the yearly minimum standings)
I have been reading a lot of posts here lately, but I admit I got confused now. I'm sure other people here are more experienced in following the Arctic, so perhaps someone can give a good summary.
Lack of aerosol can make the air clearer and let more sunlight through, but still clouds can form and block the sunlight. In any case, I don't think anyone has definitive proof (at least yet) that that shutdowns are having a measurable effect on the sea ice.
Preconditioning in May usually pays off in June and July. At this time of year it often feels as if the melting season is gone with a whimper - this will (probably) change.
6
Arctic sea ice / Re: Arctic energy balance
« on: June 03, 2020, 12:39:42 PM »
Binntho heat radiation depends on the difference in temperature. Of course you can't feel other people when you are the same temperature. But the ice is at 0o.
7
Arctic sea ice / Re: "Stupid" Questions :o
« on: June 03, 2020, 09:16:45 AM »
Binntho, I thought I made it clear that your snark was in the wrong, and yet you continue with more interpesonal mayhem. Maybe you dislike arrogance, you are certainly arrogant yourself as I am sure you are aware, I can be arrogant too, but that is not the point of this thread. The point is to answer stupid and not stupid questions helpfully, or not answer. If you dislike something, just take a deep breath and don't answer.
I have been lax, more unhelpful posts will be snipped.
I have been lax, more unhelpful posts will be snipped.
8
The forum / Re: Forum Software
« on: June 03, 2020, 02:34:08 AM »
Indeed I meant some personal choice that would enable specific bandwidth-constrained users to avoid downloads. The forum works fine for most users.
9
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: June 02, 2020, 11:37:09 PM »Quote
volume has flat lined since 2012.Min volume may have, of course it could be temporary . In any case this is an insufficient measure. Check May volume. Check 365-day moving average.
10
Arctic sea ice / Re: September predictions challenge 2020
« on: June 02, 2020, 07:44:17 PM »
JAXA: 3.5-4.0 (medium)
NSIDC: 4.0-4.5 (high)
Both bets one bin below the highest probability range, to take into account downward surprises.
NSIDC: 4.0-4.5 (high)
Both bets one bin below the highest probability range, to take into account downward surprises.
11
Arctic sea ice / Re: NSIDC 2020 Arctic Sea ice extent September average: June poll
« on: June 02, 2020, 07:41:08 PM »
Voted 4.0-4.5, it's hard to drive down the Sept average too much. 2012 had both freak compaction and a very late minimum. 2016 which was 200k away from breaking 2012's area record came in at 960k above 2012's average Sept extent. Only two years managed to hit my voted range (2007 and 2019), I am betting 2020 will do so as well, because of the early albedo losses and the relatively low volume.
12
Arctic sea ice / Re: JAXA 2020 Arctic SIE September daily minimum: June Poll
« on: June 02, 2020, 04:22:57 PM »
highest probability is for some result just above 4.00, with some downward trend added, so logic dictates 3.75-4.25 for maximum probablity. However, bearing in mind the massive preconditioning and low albedo, and the large volume anomaly near Svalbard that is at risk of being exported, extreme low results are much more probable than extreme high results. 3.0-3.5 is certainly within the realm of the possible. Thus I went for 3.5-4.0 as some kind of average. The method worked nicely for 2019, which had no GAC though I expected one.
13
Arctic sea ice / Re: The 2020 melting season
« on: June 02, 2020, 04:12:20 PM »
As compaction is area divided by extent, it tends to go up when area goes up, and more markedly if extent continues to drop.
14
Arctic sea ice / Re: The 2020 melting season
« on: June 02, 2020, 02:58:49 PM »Latest Five Day ForecastExport of thick ice to the Fram and the Barents will pick up in the next few days, hopefully it will not be sustained.
Wind @ Surface + Total Precipitable Water
15
Arctic sea ice / Re: The Arctic for Amateurs and Newbies
« on: June 02, 2020, 02:19:44 PM »
In June and July it is obvious to me that clear skies trump everything else, especially if albedo has been lowered by pre-conditioning and snowmelt. In August storms are probably worse, as they stir the warm water and move the ice to places it shouldn't be, but hide a much weaker sun. Severe August storms (GACs) have been known to generate new records.
Neven wrote somewhere in the past that the worst is a series of switches between high pressure (clear, sunny) and low pressure (storms, wind).
Hurricanes are not a good analog for arctic cyclones, warm core vs. cold core or something of the sort, I forget the details, look it up.
Neven wrote somewhere in the past that the worst is a series of switches between high pressure (clear, sunny) and low pressure (storms, wind).
Hurricanes are not a good analog for arctic cyclones, warm core vs. cold core or something of the sort, I forget the details, look it up.
16
The forum / Re: Forum Software
« on: June 02, 2020, 12:54:48 PM »
For the sake of posters who are severely bandwidth-limited, either permanently or due to traveling, I wish the forum would have a software preference switch to avoid downloading attachments of certain kinds, or over certain sizes, or simply any attachments, enabling a manual download if so desired. Is there any chance such a switch can be found?
17
Arctic sea ice / Re: The 2020 melting season
« on: June 02, 2020, 12:52:23 PM »indeed .. 745 compulsory downloads alreadyI apologize bc but it is this thread's policy to have these forecasts from time to time. I know you are under a serious bandwidth constraint but there is not much that can be done here. This thread will continue to be data-heavy. Bear in mind your message might give bad feelings to the posters involved, who are doing a community service.
I wish the forum would have a software preference switch to avoid downloading attachments of certain kinds, or over certain sizes, or simply any attachments, as for example WhatsApp does. A very useful feature. This should be taken up with Neven and/or DM in the appropriate thread or via pm.
18
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: June 02, 2020, 12:41:30 PM »
No mystery here. The NSIDC algorithm can see wet ice or melt ponds as loss of area, thus local surface freezing or snow can increase concentration. Besides, there is a reason why they use 5-day averaging - the data is known to be noisy. In general, I would appreciate if posters don't feed into wd88's posts.
19
Arctic sea ice / Re: "Stupid" Questions :o
« on: June 02, 2020, 12:29:05 PM »
Feel free to ask any relevant question, especially if you are a newbie or rarely post, with no repercussions or snark. If you are an experienced poster google should certainly be your friend as you turn to this thread, but it's not a must. If people don't care to answer, they can simply skip the question.
In any case binntho's implied snark is in the wrong, though his response may be useful in finding the answer.
In any case binntho's implied snark is in the wrong, though his response may be useful in finding the answer.
20
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: June 02, 2020, 04:50:18 AM »
We are somewhat going round in circles here. Is WAA important? yes. Does it prove DHACSOO? No, IMHO. I can understand how DHACSOO would arise when the basis of the hypothesis was watching the 2019 melting season, and imagining the surviving ice to be away from energy sources. But a look at the ice distribution in 2016 may have given rise to a completely different hypothesis.
Would you care to comment on this image, and what might explain it? What the heck happened at the North Pole? Where did the energy come from, and what's to prevent from it showing up again? And why did the ESS not bow to its proximity to a heat-advecting continent?
Compare to bathymetry and see if fits the SOO part. I think enough years show the perceived correlation to be almost a coincidence (except on the Atlantic border) - 2007 in the shallow Laptev vs. the deep ice-free CAB, 2011 and 2016 in the shallow ESS, most years in the deep but ice-free Beaufort.
My own explanation is that the ice is very mobile, and the shape of its distribution at minimum depends on prevailing winds and currents, with most years following the typical transport pattern from Siberia to Ellesmere/Greenland.
For comparison, here are the same-date images for 2007, 2011, 2012 and 2019:
Would you care to comment on this image, and what might explain it? What the heck happened at the North Pole? Where did the energy come from, and what's to prevent from it showing up again? And why did the ESS not bow to its proximity to a heat-advecting continent?
Compare to bathymetry and see if fits the SOO part. I think enough years show the perceived correlation to be almost a coincidence (except on the Atlantic border) - 2007 in the shallow Laptev vs. the deep ice-free CAB, 2011 and 2016 in the shallow ESS, most years in the deep but ice-free Beaufort.
My own explanation is that the ice is very mobile, and the shape of its distribution at minimum depends on prevailing winds and currents, with most years following the typical transport pattern from Siberia to Ellesmere/Greenland.
For comparison, here are the same-date images for 2007, 2011, 2012 and 2019:
21
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: June 01, 2020, 09:45:37 PM »
Gerontocrat normally uses the more appropriate 5-day average data from NSIDC.
Weatherdude88 uses 1-day data (when it suits his agenda of gains and recoveries).
Weatherdude88 uses 1-day data (when it suits his agenda of gains and recoveries).
22
The rest / Re: George Floyd murder and blowback
« on: June 01, 2020, 05:19:10 AM »
What a terrible situation. I hope it somehow gets resolved without further violence. It is sad to see how much the US is FUBAR.
23
Arctic sea ice / Re: "Stupid" Questions :o
« on: June 01, 2020, 02:53:47 AM »
I'm not sure I can answer your question, but about your comment on bottom melt - if you check out the Mosaic updates, the graphics posted by uniquorn and Simon show bottom melt has already begun as soon as air temps reached around -5 to 0. I guess to keep the bottom ice from melting in the salty water requires active cooling, and once it's gone the core ice temperatures climb and bottom melt begins.
24
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: May 31, 2020, 07:04:42 PM »
I cannot imagine the arch being able to hold much longer in its current unsupported configuration. The first real stress should break it. I give it 1-2 weeks. If it lasts beyond mid-June i'd be very surprised.
25
The rest / Re: George Floyd murder and blowback
« on: May 31, 2020, 07:00:01 PM »
Wili, are you okay?
26
Consequences / Re: COVID-19
« on: May 31, 2020, 06:57:26 PM »
The preposterous claim that lockdown and panic cause thousands of excess deaths can be debunked easily using some critical thinking and a scientific approach. Find countries that had a severe lockdown and lots of panic, but a low rate of actual infection. If half the UK excess mortality is due to panic and lockdown, you would expect these other countries to have thousands of extra deaths due to people avoiding hospitals. If most or all UK extra deaths are due to COVID, you would expect these countries to not have thousands of extra deaths.
Israel is one such country, with a very long and severe enforced lockdown and drummed up panic by the psychopath-in-chief Netanyahu (which once and for all seems to have done something right). I do not have access to mortality data but have read in articles that even with the 284 confirmed COVID deaths, there was no excess mortality at all (or barely so), due to lower death rates from other causes during the lockdown, e.g. traffic accidents, and due to the normal death rate being much higher than 284 over the two relevant months.
So: do panic and lockdown cause thousands of excess deaths? Of course not. Truly bizarre claim.
BTW, I believe Austria is another such country, with panic and lockdown but low infection rate. Anyone has access to Austrian total mortality numbers? Someone living in Austria?
Israel is one such country, with a very long and severe enforced lockdown and drummed up panic by the psychopath-in-chief Netanyahu (which once and for all seems to have done something right). I do not have access to mortality data but have read in articles that even with the 284 confirmed COVID deaths, there was no excess mortality at all (or barely so), due to lower death rates from other causes during the lockdown, e.g. traffic accidents, and due to the normal death rate being much higher than 284 over the two relevant months.
So: do panic and lockdown cause thousands of excess deaths? Of course not. Truly bizarre claim.
BTW, I believe Austria is another such country, with panic and lockdown but low infection rate. Anyone has access to Austrian total mortality numbers? Someone living in Austria?
27
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 31, 2020, 06:40:28 PM »
Paolo, I added the text from #2274 to #2249.
28
Consequences / Re: COVID-19
« on: May 31, 2020, 12:19:33 AM »
In Israel a second wave could be beginning. Daily cases went from ~10-20 to ~100 within 3 days, after 3 weeks of stability. Many infections and clusters are school-related.
29
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 30, 2020, 01:39:37 PM »
In short, WAA can melt snow, reducing its albedo and letting in the real monster, sunlight. So you cannot completely discount it no matter what calculations show regarding total energy transferred.
30
Consequences / Re: COVID-19
« on: May 30, 2020, 10:34:16 AM »They do say it... under most likely scenario.The CDC's estimate is 0.4% for symptomatic cases, so the answer does not lie in the "dark cases". Looking at the CDC's table 1, no source is listed for the CFR, except the dubious "Source: Preliminary COVID-19 estimates, CDC".
https://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scenarios.html
Symptomatic CFR 0.004
Asymptomatic cases: 35%
0.004 * (1-0.35) = 0.0026
The CDC estimate seems not to fit the data very well. Not just NYC, but lots of other places.
If CFR is 2-3% in lots of places, then 10 symptomatic cases are out there for every 1 that is 'identified'. Meanwhile positive test are down below 1 in 10 in many places. So just where are all these 'dark' COVID positive cases hiding?
The bibliography below the two tables is very sparse, with one source for COVID epidemiological estimates and one for influenza. Weirdly, the one source for COVID is a meta-analysis that estimates CFR as 2%...
Bottom line, I find the CDC estimate to be dubious, certainly requiring a more detailed explanation.
31
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 30, 2020, 10:17:00 AM »
On another note, you seem intent on proving that WAAs are very important to the Arctic, and that they do matter. I am not sure why you think this needs proving, it's quite obvious. The question raised by this thread is whether locations that do not often receive WAAs (away from continental landmasses) are highly likely to retain ice at minimum over the next decade, thus enticing a slow transition. To prove this, even just logically with no supporting quantification, requires more than just proving that WAAs are important.
Be aware, anyone can calculate simple formulas learned on the forum, and most anyone can use Excel or OpenOffice to make some statistics. It doesn't take a PhD, it's not difficult, but one must decide they want to invest the time and make the contribution.
And regarding that thread - many posters on this forum began their residence as lay persons, myself included. To most intents and purposes I am still a lay person, but I make it my business to learn anything I can, enhancing my own understanding and hopefully enabling some more personal contribution. Despite great difficulties in my first year on the forum, and lots of things being total gibberish to me, I recall trying to follow the discussion and even to post some useful(?) questions in that thread at the time. Make it your business to understand the detailed and difficult stuff, and your contribution to the forum will grow accordingly. Skip the hard stuff, and your contribution will be limited to lots of words with no supporting evidence.Also, read the Slow Transition thread from start to finish, very relevant.
You took the words right out of my mouth Oren!
I have perused the Slow Transition thread. It doesn't seem like a discussion that is designed for the lay person.
Be aware, anyone can calculate simple formulas learned on the forum, and most anyone can use Excel or OpenOffice to make some statistics. It doesn't take a PhD, it's not difficult, but one must decide they want to invest the time and make the contribution.
32
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 30, 2020, 10:02:49 AM »Quote
Let's separate my suggestion into two elements. The first element is the suggestion that we should strive for proactive measures which give a better sense of what the season portends. The second element is the specific suggestion that the measure be (CAB + CAA + Beaufort).We have discussed it on the forum in the past. My position was and still is that as far as area data goes, the most relevant data is an aggregation of all the seas connected to the Inner Basin with import-export ties, plus the CAA because of its peculiar geography and ice retention. This is because the ice in these seas can move to the CAB, or be received from the CAB, thus making them one interconnected system. The same applies to energy and enthalpy in these regions. Seas that should be excluded are seas that mostly see export from the Inner Basin due to prevailing currents and winds and due to high local melt: Baffin, Barents and Greenland Sea. These seas may retain ice at minimum but that ice is not the ice that is there now, rather it's ice that will be exported to them in August or September.
As far as the second suggestion, I would consider it to simply be a straw man. If the best minds think ESS or Greenland Sea s/b included, I think that's a step in the right direction and would be very pleased with that 5 sea indicator of intra season progress relative to the end game.
As far as the first element, what are your thoughts there ? Do you think this is a direction to pursue? How do you feel about the 5 sea comparison which I infer that you might like better? You are the moderator here, I'm happy to defer to your judgement.
Funnily enough, this is exactly the index tracked by the relentless Gerontocrat in his area updates and other updates: the High Arctic + CAA. Not because I am a moderator (irrelevant) or because that is my position, but because this has been discussed in the past and it makes sense. And because it's Gerontocrat's position of course. I track this index too in my regional PIOMAS updates, when I get around to making them. Wipneus has an Inner Basin chart that excludes the CAA. Each person that publishes statistics regularly can choose his or her own index to track, feel free to do the same. But if the stats are considered irrelevant by most of the forum, such contributions should be short and to the point and not cause too much noise and clutter. 2-3 lines of daily text and data are welcome, loads of text and repetitive analysis every day will be frowned upon. This happened in the past with some users.
Things change in August: the CAB starts crashing, and the single most important index by then is the CAB itself. But changes in the CAB will be a result of 2D developments that took place in the surrounding seas, and 3D processes in the CAB itself, all unseen in the CAB 2D data. Until August, all you see in the CAB area and extent data is noise (and the local variability of the sector near Svalbard-FJL, which should have been excluded from the CAB).
Note the best 2D index IMHO would be a pixel-level aggregation of ice concentration multiplied by the difficulty of clearing ice from that location, as measured by the statistics from the past 10 years. Thus a year that melts ice near the North Pole (such as 2016) gets more points than a year with early advances in the southern Kara. But this index is currently unavailable.
33
Arctic sea ice / Re: MOSAiC news
« on: May 30, 2020, 02:00:50 AM »
Thanks for the update. All are changes for the worse and support the loss of albedo inferred by temps and satellite images..
34
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 29, 2020, 10:27:38 AM »
Two comments off the cuff:
* In the Chukchi and in the Svalbard-JFL line, we have not just a shallow shelf but also an incoming oceanic current which is warm and salty. These current are prevented from sinking below the cold fresh water, thus enhancing ice melt. Ignoring the effect of prevailing currents in general, and these two currents in particular, can lead one to the conclusion that shallowness is a factor in itself.
Other shallow regions do not have these currents and do not have the tendency of enhanced ice melt. Specifically, the ESS is the shallowest Arctic sea and also the most difficult to melt. OTOH, the deep Beaufort is continually fed by thick ice from the CAB during the melting season, as can be seen in the long-term animations upthread and in animations from various melt seasons. Thus its resilience is partially a mirage of ice import.
* I know you do not consider quantification an essential tenet of the hypothesis. However, once a quantification has been served by others I think it shouldn't be ignored.
"Since over 90% of the season ending ice is expected to be in the CAB, CAA and Beaufort, it would be a simple tweak to create a category for the sum of these three seas instead of the current High Arctic grouping."
I have posted data in the Melting Season thread showing that on average more ice survives in the ESS than in the Beaufort. Besides, 90% of the Beaufort and ESS ice is expected not to survive a given melt season. And what about the Greenland Sea? Thus I think your proposed "survivable ice" measure would not be quite helpful.
* In the Chukchi and in the Svalbard-JFL line, we have not just a shallow shelf but also an incoming oceanic current which is warm and salty. These current are prevented from sinking below the cold fresh water, thus enhancing ice melt. Ignoring the effect of prevailing currents in general, and these two currents in particular, can lead one to the conclusion that shallowness is a factor in itself.
Other shallow regions do not have these currents and do not have the tendency of enhanced ice melt. Specifically, the ESS is the shallowest Arctic sea and also the most difficult to melt. OTOH, the deep Beaufort is continually fed by thick ice from the CAB during the melting season, as can be seen in the long-term animations upthread and in animations from various melt seasons. Thus its resilience is partially a mirage of ice import.
* I know you do not consider quantification an essential tenet of the hypothesis. However, once a quantification has been served by others I think it shouldn't be ignored.
"Since over 90% of the season ending ice is expected to be in the CAB, CAA and Beaufort, it would be a simple tweak to create a category for the sum of these three seas instead of the current High Arctic grouping."
I have posted data in the Melting Season thread showing that on average more ice survives in the ESS than in the Beaufort. Besides, 90% of the Beaufort and ESS ice is expected not to survive a given melt season. And what about the Greenland Sea? Thus I think your proposed "survivable ice" measure would not be quite helpful.
35
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 29, 2020, 02:26:09 AM »I'm a little surprised, but I didn't find (by searching with google) any other echo of the calving than this oneWrong search, at least judging by Steff Lhermitte. Short gif at link.
Wrong search or it's like this?
https://twitter.com/StefLhermitte/status/1265410528454811654
36
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 28, 2020, 03:17:41 PM »
Quantifying: in the last 10 years there were two August GACs - 2012 and 2016. Both years are also lowest in NSIDC area, similar to each other and far ahead of other years.
Thus, chance of GAC is ~20%/year. Not freak. To break the area record it is probable another GAC will be needed. Ergo, chance of new area record is 10%-20% per year. Or 15%-25%, depending on your assumptions about other factors.
Note: 2012 has a huge lead in min extent, thanks to freak Sep compaction. But area is IMHO more representative of energy in the system.
Thus, chance of GAC is ~20%/year. Not freak. To break the area record it is probable another GAC will be needed. Ergo, chance of new area record is 10%-20% per year. Or 15%-25%, depending on your assumptions about other factors.
Note: 2012 has a huge lead in min extent, thanks to freak Sep compaction. But area is IMHO more representative of energy in the system.
37
Arctic sea ice / Re: The 2020 melting season
« on: May 28, 2020, 08:34:17 AM »
One can always hope, but I believe no serious correlation has been found between ENSO cycle and Arctic sea ice.
This can be discussed further in Does El Niño affect Arctic sea ice?
This can be discussed further in Does El Niño affect Arctic sea ice?
38
Consequences / Re: The 100th Meridian aridity line: is it really moving east?
« on: May 28, 2020, 08:30:35 AM »
Lol, my bad. Kerguelen is almost double my distance...
39
Consequences / Re: The 100th Meridian aridity line: is it really moving east?
« on: May 28, 2020, 04:53:42 AM »
I can't comment on the subject, I live about as far away from the Great Plains as possible, but I must say this was an extremely interesting eye-opening post. Well Written.
40
Arctic sea ice / Re: meaningless freezingseason/melting season chatter.
« on: May 28, 2020, 02:41:38 AM »
Nice find. BTW, if you look closely, you can see he is holding his mobile and browsing the ASIF.
41
Arctic sea ice / Re: The 2020 melting season
« on: May 27, 2020, 08:07:29 PM »Has anyone seen the Laptev sea today on Worldview? The inner half is so dark, but it almost looks like a camera glitch because the contrast line is so straight and sharp, like that of a giant shadow. But it shows up on all the true color feeds. Is it real?I am sure it's real. Temps not far from the Laptev have been soaring in the past few days.
42
Arctic sea ice / Re: The 2020 melting season
« on: May 27, 2020, 06:12:27 PM »
Simon, thanks for the interesting calculation. Bear in mind albedo reductions are not 40 days ahead of other years. As Phoenix said it is more reasonable to assume a week or two-week advantage averaged across the whole pack. This still would result in a whopping 15cm of added melt, which IMHO is a huge extra.
43
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 27, 2020, 12:02:46 PM »
Thanks, well explained.
The pixel-level analysis you described is something I have wanted to do a long time ago and still want to, however I currently lack the skills and especially time to do so. I know the data is available and that it is a feasible calculation, if I have a couple of free months I know I can do it including acquiring the programming skills. Won't ever happen probably.
For each pixel, what is the probability of being ice-covered or ice-free (or % ice concentration), for each given date, looking at statistics from the last 10 years (since 2010 when the Arctic sea ice statistics seem to have stabilized a bit). Best displayed as a color-coded map of probability, animated over the days of the year.
Even better would be to compare this animated map with one containing the data of previous decades (2000-2009, 1990-1999).
A map for AMSR2 data (since 2012 or 2013), and for NSIDC data (full data available), as these have different pixels and vastly different resolutions.
Missing data would have to be interpolated from preceding and following days.
By the time I get down to actually doing it, the Arctic will probably be post-BOE...
I have made do with aggregated regional data, especially the finer AMSR2 data from Wipneus, but also the NSIDC area data. This gives some crude conclusions and insights but is mostly unsuitable to the huge and diversified CAB, in fact to any region that is made up of different ice behaviors or geographies.
Let's wait and see what this season will bring. If I have further contributions to add, I will post them here or in the "when ice free" thread.
The pixel-level analysis you described is something I have wanted to do a long time ago and still want to, however I currently lack the skills and especially time to do so. I know the data is available and that it is a feasible calculation, if I have a couple of free months I know I can do it including acquiring the programming skills. Won't ever happen probably.
For each pixel, what is the probability of being ice-covered or ice-free (or % ice concentration), for each given date, looking at statistics from the last 10 years (since 2010 when the Arctic sea ice statistics seem to have stabilized a bit). Best displayed as a color-coded map of probability, animated over the days of the year.
Even better would be to compare this animated map with one containing the data of previous decades (2000-2009, 1990-1999).
A map for AMSR2 data (since 2012 or 2013), and for NSIDC data (full data available), as these have different pixels and vastly different resolutions.
Missing data would have to be interpolated from preceding and following days.
By the time I get down to actually doing it, the Arctic will probably be post-BOE...
I have made do with aggregated regional data, especially the finer AMSR2 data from Wipneus, but also the NSIDC area data. This gives some crude conclusions and insights but is mostly unsuitable to the huge and diversified CAB, in fact to any region that is made up of different ice behaviors or geographies.
Let's wait and see what this season will bring. If I have further contributions to add, I will post them here or in the "when ice free" thread.
44
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 27, 2020, 11:40:46 AM »
I think the best method to show the long term acceleration is to make an animation of the whole front with a proportional timescale, for example 1 or 2 or 4 images per month, over the last 10 years or so.
If images are not available from certain times, one can double the previous image, so as to maintain the sense of time.
I have seen several such animations on Twitter (Steff Lhermite for example) but they do not cover the final acceleration this year. The best animation would be rather large, rather slow, and have a pause at the end, to enable the viewer to take in the developments. A date or year counter would be quite helpful. Animation should be fixed to grid, not to any moving point. This will enable the viewer to follow the gradual dance of forward movement and calving, the net of which is the retreat.
I am not doing this myself unfortunately due to severe lack of time (and abilities), but if anyone is able and willing it would be much appreciated.
If images are not available from certain times, one can double the previous image, so as to maintain the sense of time.
I have seen several such animations on Twitter (Steff Lhermite for example) but they do not cover the final acceleration this year. The best animation would be rather large, rather slow, and have a pause at the end, to enable the viewer to take in the developments. A date or year counter would be quite helpful. Animation should be fixed to grid, not to any moving point. This will enable the viewer to follow the gradual dance of forward movement and calving, the net of which is the retreat.
I am not doing this myself unfortunately due to severe lack of time (and abilities), but if anyone is able and willing it would be much appreciated.
45
Arctic sea ice / Re: The 2020 melting season
« on: May 27, 2020, 03:24:20 AM »
Rob Dekker had/has a model predicting the outcome of melt seasons using the continental snow anomaly. I always thought the model too simplistic, but there's certainly a correlation there. Whether the causation is obvious (albedo and other feedbacks) or not so much (warm weather affecting both land snow and sea ice) is another matter.
Just don't start a continental snow/WAA crusade, this can be discussed in more depth elsewhere/in your own thread if so desired.
Just don't start a continental snow/WAA crusade, this can be discussed in more depth elsewhere/in your own thread if so desired.
46
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 27, 2020, 03:07:25 AM »
Thank you. I have been following all the updates here in detail, but we have some readers who may be newbies or lurkers who could greatly benefit from the extra information.
47
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 26, 2020, 05:50:41 PM »
Yes, thank you Paolo. I recommend adding a legend somewhere though.
48
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 26, 2020, 04:28:39 PM »Quote
Next question. Why does ice adjacent to Siberia begin melting earlier than ice in the CAA which is at the same latitude? Insolation s/b the same +/- some cloud anomaly. Water temp s/b < 0 before the ice begins melting.I wish you would attempt to quantify your hypotheses.
I see proximity to heat from land as the trigger to begin melting, preconditioning, etc. Perhaps you see it differently?
Does the CAA start melting later than the ESS? I think not, judging by the AMSR2 area graph.
Why does the Beaufort start melting much earlier than the ESS? Same latitude, same proximity to landmasses, and deeper bathymetry.
The answer to all these questions is prevailing currents and ice movement.
Note if the CAA ice was not landfast, it would have been flushed south and melted much earlier every year. So the CAA is a really bad example.
49
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 26, 2020, 06:57:10 AM »
Sorry, laziness, theory is a shorter word to type.
50
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 26, 2020, 05:38:51 AM »
Another thing to bear in mind is that temperature is a problematic indicator over the Arctic. As long as there is abundant sea ice, summer surface temps will be pinned to the ice melting point, while the ice might get thinner and thinner. Besides, the Arctic can get a lot of its melting energy directly from the 24-hour sun, with albedo and cloudiness playing an important mediating role in this process.