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Fisch

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #300 on: October 27, 2014, 02:30:05 AM »

Max/min thickness seems to arrive about a month/month-and-a-half after when max/min extent/area/volume arrive. Anyone know the reason behind this?

The thickness is average thickness. When the freeze begins it adds lots of area of thin ice while it isn't cold enough to thicken thick ice. Thus the average thickness continues to decline past the point where ice is being added.

Similarly when the melt begins, it begins by melting out thin ice.
Thank you kindly.

A while back, Planet3.org ran a piece on methane, and the comment discussion turned to Shakhova et al. Andy Skuce was involved, and he noted:

"The quantitative results of [Shakhova and Semiletov's] 'field experiments' have gone publicly unreported since 2010, despite the fact that, from second-hand reports, S&S consider that their findings mandate urgent action."

Not being a scientist of any kind, or especially skilled in following the language used in science writing, I don't know what this means. Shakhova et al have been publishing papers since 2010. So are the "quantitative results" the actual records of emissions from specific sites? Detailed maps showing pockmarks and taliks on the seafloor? Sonar maps? And what is the nature of their experiments?

(I asked this over at Planet3, but got no response; it's a fairly old thread.)

wili

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #301 on: November 29, 2014, 01:41:30 AM »
So, I assigned the intro to Lynas's Six Degrees to one of my classes. Someone in the class pointed to the passage that talks about how, even though 6C may not sound like much, it was the difference between today's relatively temperate NYC and an iceage era NYC area with a mile of glacier over it.

But someone else pointed out that you could probably go a couple hundred miles north of NYC and the temperatures on average would be that much colder than NYC today, but it (say, Nova Scotia) is not under a mile of ice. (She actually didn't quite say it that clearly, but that was the gist.)

I kind of waffled at the time. But when I looked into it, I found something unexpected (to me at least--probably completely 'duh' obvious to the rest of you):

First of all, apparently the cooling distributed evenly over the surface of the earth. There was less or none of it over the equatorial/tropical regions, especially over water. (So that's the first question--Is that anywhere near the ball park? It makes sense to me, but lots of things end up being rather counter intuitive in this field, I find.)

Second (and this was the part that I found a bit surprising), the distribution of the cooling across the year was also not evenly distributed: the winters over much of the norther hemisphere were actually a bit warmer than current averages. I always thought of the ice age as unimaginably cold. But over much of the north it may have been a bit warmer (but longer) than what we experience in MN. All you need to freeze things is for temps to be generally below 0 C enough of the time that warming spells don't totally thaw it.

So a longer, though warmer, winter combined with a shorter and much cooler summer was enough to tip the balance in much of the NoHem so that more ices was formed every winter than was melted every summer...and then it's just a matter of piling on the years and the ice layers.

Does that sound about right? I foraged this from a number of sources that I can't recall right now. So if anyone has any points where I'm off (or especially if I'm completely full of bollocks!) or if you can point me to any (perhaps slightly user friendly?) sources to shore up my weak understanding of these things, it would be greatly appreciated.

Those effects have to do with how the sun hits the earth and affects the seasons when the tilt of the axis goes closer to straight up and down; so far northern and far southern climes are not tipped as directly toward the sun during their summers, hence the cooler summers. But conversely they are tipped closer to the sun during their winters, hence the warmer winters.

Thanks ahead of time for any corrections, pointers, or even face palms  ::) !
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

OSweetMrMath

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #302 on: November 29, 2014, 04:13:18 AM »
Wili,

I went poking around on Wikipedia to try to understand the current climate of New York City and what it would be like at 6C cooler. Climate information on Wikipedia is remarkably inconsistent (otherwise identically formatted tables on different pages having additional or missing rows and columns, etc.) so I can't point to a bunch of references to back my claims up, but here is my impression:

If you are asking what a local temperature change of 6C would do to New York's climate, the first question is whether that's before or after the urban heat island effect. The annual mean temperature for NYC is around 15C, but with a large UHI boost. Without that effect it would be closer to 12C.

Assuming we're talking after the UHI, we're looking for somewhere in Canada with an annual mean around 6C. This is where my Wiki searching really started to fail me, but my impression is that Nova Scotia isn't far enough north to be that cold. (Because it's an island, the ocean has a strong moderating effect on the temperature.) You might have to go closer to the mouth of the St. Lawrence to be in the right temperature range, but I was unable to find a good comparison.

My readings generally supported your other two claims. It's easy to imagine that warmer winters and colder summers would result in a much longer snow season.

And on the point that temperature changes are not globally uniform, the discussion of the NYC climate pointed out that NYC is currently much warmer than most other American cities of the same latitude, again largely due to the moderating effect of the Atlantic Ocean. It's reasonable to assume that with a large global temperature change, NYC would lose that effect and see a much larger temperature change than the global mean change.

Laurent

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #303 on: November 29, 2014, 10:30:42 AM »
Wili,

If the question was :
what will happen if -6°c in average happen ?
If I am correct reading the various graphs, It has never happened in the million year.
At the last glacial low we were at -5°c and there was some glaciers in Florida.

What will happen if +6°c happen :
The Antarctic is melted, it is hot, it did happen around mid eocene, 40 million years ago.

The last graph show around -3°c instead of -5°C in Hansen (not sure if I am reading that correctly). I don't know what that mean equivalent Vostok delta T ! Certainly the average temperature in Vostok !?

Rereading your question, I want to say that yes there was some big differences between winter and summer, but I don't think life was possible inland under a mile thick of ice. Around New york, yes it was certainly possible because of the sea nearby, look at what is happening in Antarctic, life is thriving near the sea.
« Last Edit: November 29, 2014, 11:07:55 AM by Laurent »

wili

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #304 on: November 29, 2014, 02:47:06 PM »
Thanks for the discussion, L and OSMM.

I didn't mean for the discussion to be particularly around NYC and Nova Scotia--those were just examples from the 6 Degrees book and my random jab at a place sufficiently far north. But yeah, they're both unfortunate choices for random examples in that they both are heavily influenced by the ocean.

I was mostly interested in the apparently uneven distribution of heat (or of the cooling, if you will) in both space and (especially) time (over the course of a year).

Thanks especially for the cool graphs, L. I love graphs!
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crandles

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #305 on: November 29, 2014, 03:02:34 PM »
Warming or cooling is generally greater over land than oceans. There is also usually polar amplification - more so in the Arctic than Antarctic particularly for recent periods but if you go back to the Eemian without ice sheets then the polar amplification should be more similar.

If going back a long period of time you may also have to consider Milankovitch cycles. A more tilted earth can give a lot more insolation to high latitudes during the summer and this can make the difference to whether the snow and ice manages to melt.

crandles

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #306 on: November 29, 2014, 03:16:03 PM »
Here is a review article of history of Last Glacial Maximum (LGM) science:

http://www.sciencedirect.com/science/article/pii/S0277379114003679
(freely available until 23rd December)

Estimates have varied but latest estimate is 4C global average cooler than now preindustrial for LGM. I'd suggest a few thousand miles nearer pole would be needed to keep the same temperature. If a species can't move that fast/far perhaps easier still is move up a few hundred meters. Trouble is as you move up and so does everything else, space soon runs out as you approach top of mountains.
« Last Edit: November 29, 2014, 03:49:11 PM by crandles »

viddaloo

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #307 on: December 11, 2014, 10:57:31 PM »
— The path to perennial open water is paved with local and seasonal zeros!

If you want to get to a state of zero ice everywhere all days of the year, you will need a lot of zeros. In fact, a sea ice volume of zero for any given location or day is the lowest that data point can go, and therefore 'the best' from the perspective of getting to zero fast.

Now, on this forum the majority of those who speak out on the issue of decline speed and hitting zeros seems to be of the opinion that getting a lot of zero data points is *BAD* for the decline speed. That will slow the decline down, seems to be the conventional wisdom on this site. The graph will flatten or at least become less steep, when lots of points report a zero.

How can this be? From the amateur perspective the thaw couldn't do any better than, say, increase the number of ice–free days in the southern Arctic oceans from 100 to 200. It can't get to the Big Zero without the southern Arctic oceans reporting 200 ice–free days, and later 365 ice–free days a year.

According to experts, the same amount of energy used to melt a square meter of sea ice from 0C ice to 0C water on one day, could heat the same square meter of sea from 0C water to 80C water temperatures on the next. Of course, this doesn't happen exactly like that, but the example communicates how hard it is to melt ice, and how much the Arctic oceans will be heated (by the sun etc) when that ice is gone. Relevant in our context is that nothing stops at zero ice volume.

I put it to you: Instead of slowing the decline down, the complete melt of an increased area or an extra day will *SPEED UP* the decline rate, and increase the steepness of the collapse graph.

[I post this text in the Stupid Questions department, as in the great Nordic tradition of H.C. Andersen's fairytale 'The Emperor's New Clothes', the child (or amateur) is able to both ask stupid questions and to ask real simple and obvious questions that the grownups (or experts) have learnt not to ask. This means it could both (either) be stupid or revealing. I don't really care which of them it is, as I want to get to the answers, and then questions are the obvious tool. So this topic really begs the question!  ;D]
« Last Edit: December 11, 2014, 11:04:13 PM by viddaloo »
[]

crandles

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #308 on: December 12, 2014, 12:36:13 AM »
Says it all really. You haven't a clue about the vast majority of the heat built up over summer being vented to atmosphere and space.

Yet
I understand CR has a blog post with a theory. That doesn't mean it's correct or that all math tools immediately stop giving meaningful results. I, for one, don't think CR is correct about the Arctic sea ice collapse. I think others have a better understanding of the forces at play here.

I don't see any reason not to interpret this as

I haven't a clue but I know I am right and he is wrong and I have no interest in learning why I am wrong.

Perhaps if it was just once, I ought to be more forgiving but when you do it repeatedly then it is way past time for me to give up on you unless you learn to have lot more humility.

viddaloo

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #309 on: December 12, 2014, 01:10:43 AM »
I think playing with completely open cards and asking in the 'Stupid Questions' thread is quite humble, and I'm looking forward to all the good answers during the coming weeks.

I also think the question is a bit more complicated than melting always being bad for the melt. Perhaps it's bad for melt part of the time, but not always? In any case, it seems reaching zero ice at least till now has served to make the collapse graph steeper. Maybe that could change in the future?
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LRC1962

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #310 on: December 12, 2014, 02:03:41 AM »
Second (and this was the part that I found a bit surprising), the distribution of the cooling across the year was also not evenly distributed: the winters over much of the norther hemisphere were actually a bit warmer than current averages. I always thought of the ice age as unimaginably cold. But over much of the north it may have been a bit warmer (but longer) than what we experience in MN. All you need to freeze things is for temps to be generally below 0 C enough of the time that warming spells don't totally thaw it.
As I used to live in the Maritime Provinces of Canada it would be somewhat obvious. The biggest snowfalls almost always come when the temp is above -10C. You can get snowstorms that come below that, but rarely below -20C. Any storms that do come below -10C the flacks tend to be very small and accumulations very low. I can not tell you the whys of it as I have never studied it, but I do know that is what happens. That is part 1 of why you would have mile high glaciers. Part 2 would be very cold summers. So let us imagine that you would have a large polar low sitting over most of NA during the summer, but in the winter you got warm moist high coming up from the south with the jet stream bringing systems across from the pacific getting cooled of by the Arctic around the 40-45 latitudes. This would give you lots of big snowstorms and at the same time keep the temps in the summer cold enough that there would be limited snow melt. The other point is the the equatorial lat. would have be warm in order to get enough moisture up into those lat.
With the jetstream running that far south the Arctic could on average have been warmer as you would need warm systems in the Arctic to push the cold down to those lat.
Could have my physics entirely wrong but I do think that would be how things would work out.
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icefest

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #311 on: March 18, 2015, 12:55:54 PM »
Another stupid question:

Does anyone know what happened to the sea ice extent chart from uaf?

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
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crandles

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #312 on: March 18, 2015, 01:10:28 PM »
Can you find it from

https://ads.nipr.ac.jp/vishop/vishop-monitor.html?N ?

If not do you have an example of what it looked like?

icefest

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #313 on: March 18, 2015, 02:40:09 PM »
Thanks crandles.
This was the closest, and I'll guess it'll be my go-to replacement:
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crandles

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #314 on: March 18, 2015, 02:48:00 PM »
Thanks crandles.
This was the closest, and I'll guess it'll be my go-to replacement:

There is a button that shows each year since 2000 (which is actually 2002 onwards) just below that chart either grey or pink depending which is selected if that helps any further.

ktonine

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #315 on: March 18, 2015, 09:38:22 PM »
Wili --For glaciers to form you need snow to accumulate year-to-year. Summers have to be relatively short, and/or cool enough that not all the snow melts. And as LRC points out, there is a sweetspot for snow.  Nate Silver ran the data for NY and it was between 20 and 32F.

There is, as you note, a surprisingly small difference in *global* temperatures between glacials and interglacials.  When we consider that the changes are not uniform, and that we only need summers to be cool enough to leave a little snow left over from what fell that winter, 6 degrees C *globally* is more than enough to see glaciers in NY city - though I'm sure it would take thousands - tens of thousands - of years to reach thickness approaching a mile.

cats

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #316 on: March 19, 2015, 12:40:41 AM »
Besides the more interactive one that crandles posted, there is also this chart - https://ads.nipr.ac.jp/vishop/data/graph/Sea_Ice_Extent_N_prev_v2_L.png

opensheart

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #317 on: March 19, 2015, 04:06:11 PM »
Could someone post a good explanation of the following to the glossary thread in the forum.
     NSIDC
     JAXA
     CT – Cryosphere Today
Like similarities and differences, how they are computed, what they mean, who usually uses each and why?

NSIDC is referenced in the glossary, but not really defined.
I’m not finding JAXA in there at all
And CT is just defined as Cryosphere Today.

I’m looking for more than just the organization each come from.   When people use these names, they are usually referring to a specific measurement.   So these acronyms come to mean more than just an organization.   They seem to mean a specific kind of measurement done a specific way.   And there seems to be an unspoken assumption that each is to be understood to mean something different.   

Like I usually assume people are talking about NSIDC ‘extent’ graph when they reference NSIDC.   But for some reason, I usually assume people are talking about some kind of ‘area’ measurement when they talk about CT.   But I have followed this blog for a long time and have no idea what JAXA means.

I think a glossary entry defining in one place, the different kinds of measurements people refer to could be helpful.

icefest

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #318 on: March 20, 2015, 04:49:33 AM »
Besides the more interactive one that crandles posted, there is also this chart - https://ads.nipr.ac.jp/vishop/data/graph/Sea_Ice_Extent_N_prev_v2_L.png
That's exactly the one I was looking for!
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icefest

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #319 on: March 20, 2015, 04:56:54 AM »
Continuing with the silly questions:
Would it be possible to use heat flux to measure comparative ice thicknesses?
I'm assuming not, because when ice is thicker than 50cm the instrument error would be greater than the actual surface temperature.
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LRC1962

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #320 on: March 26, 2015, 03:48:31 PM »
I have a question. When scientist project into the future they seem to have no trouble using curved graphes, yet when drawing real time trends such as temp changes or ASI it seems that the majority draw straight lines even though it is obvious that a curve would be a better choice. Is that so any future erratic shifts can still fit within the 2 sigma?
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crandles

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #321 on: March 26, 2015, 04:17:52 PM »
Projecting curves is difficult because there are any number of curves that can fit the data very well but the projections from different types of curve can be very different. So you have to know the science very well to know what curve type to use for an extrapolation.

Where you see curved projections they are based on assumptions that are then processed to produce the projections and almost never do you see extrapolation of data with anything other than a straight line. (Mores law sees likes a curved projection from data but it is really a straight line extrapolation of data on a log scale graph.)

slow wing

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #322 on: March 27, 2015, 10:46:54 AM »
There are reports of the Gulf Stream already slowing down:
http://icelandreview.com/news/2015/03/25/nature-gulf-stream-slows-down-impacting-iceland

Could this already be lessening the transport of heat to the Arctic sea ice and therefore lessen the melt for this, and future, melt seasons?

Thanks.

Pmt111500

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #323 on: March 27, 2015, 11:55:21 AM »
There are reports of the Gulf Stream already slowing down:
http://icelandreview.com/news/2015/03/25/nature-gulf-stream-slows-down-impacting-iceland

Could this already be lessening the transport of heat to the Arctic sea ice and therefore lessen the melt for this, and future, melt seasons?

Thanks.
My guess here:
nope. shifts the bulk of the melt on the Pacific side. Sets a permanent Icelandic low southside of it. Throws the NA drift to Bay of Biscay, wherefrom rounds Bretagne, hits Arctic later than previously, maybe slightly cooler. Increases atmospheric heat transport both in the Pacific side and over Europe. Keeps the Atlantic coast slightly cooler, but the effect is very small. Not going to bet on this one.

johnm33

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #324 on: March 27, 2015, 06:51:46 PM »
There are reports of the Gulf Stream already slowing down:
http://icelandreview.com/news/2015/03/25/nature-gulf-stream-slows-down-impacting-iceland

Could this already be lessening the transport of heat to the Arctic sea ice and therefore lessen the melt for this, and future, melt seasons?

Thanks.
Follow the various links here http://www.rapid.ac.uk/rapidmoc/ for more info.
My take on this 1, the cold area suppresses the northward flow, which will pass beneath it. 2, suppressed flow runs the risk of releasing a torrent of basal arctic water through Fram at some critical threshold.[To be replaced from the Pacific?] 3 Retained water heats up creating an enlarged differential between the Gulf/eastern seaboard and North Atlantic [and North America]= storms. 4, Cool [wet?] growing season in Europe.
If you stop this animation and click through it you'll see that despite the cold anomoly there's still a warm anomoly stretching around Norway into the Arctic.
http://www.esrl.noaa.gov/psd/map/clim/sst.anom.anim.year.html

Chuck Yokota

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #325 on: April 08, 2015, 03:44:48 PM »
Has there been a discussion here on the forum about the stability of the halocline (that keeps a cap of colder and fresher water over the warmer and saltier deep waters) and how it might be affected by declining sea ice? Or could someone provide links to information on this topic?

Gray-Wolf

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #326 on: May 12, 2015, 01:48:07 PM »
I also wonder about the mixing out of the Halocline that open water has led to?

Currently I'm also troubled by finding dats on the influx of Pacific water through Bering? Anyone got any idea of recent temps and amounts of the inflow since we saw the triple R form and 'The Blob' develop?

If we have the Beaufort Gyre with Atlantic and Pacific waters stacked on top of each other what happens if the waters bodies near parity in temp/salinity? Do they mix out?

As it is we must be seeing some quite warm water flowing into the basin via 'the blob' and this appears set to continue as the blob is reinforced by the waters of the latest Kelvin Wave ( surfacing at the Americas currently) as it flows north to join with 'the blob'.

We have seen the impacts of warm Atlantic inflow into the Barentsz area drove so could we expect this , and next?, years ice in Beaufort to suffer more aggressive basal melt?
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Jim Hunt

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Bruce Steele

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #328 on: May 12, 2015, 05:03:32 PM »
Grey-Wolf, There are active ITP Buoys that profile salinity and temperature profiles across the arctic.
Buoy # 78 is currently positioned to get some idea about Pacific warm water and mixing as it enters the Beaufort Gyre. You can monitor changes as the season proceeds but after watching for a couple years I haven't ever seen upwelling or mixing completely break down the surface freshwater. You need to watch both salinity and temperature to spot any major upwelling events that may ( in the future ) break the surface. The strength of the Beaufort Gyre determines whether the surface fresh water says in the Canadian Basin or more quickly moves towards the exit into the Atlantic.
 Here is a paper that better describes the part the Beaufort Gyre plays.

  http://www.whoi.edu/fileserver.do?id=94184&pt=10&p=25592
 
I am interested in the same type of questions you are asking re. mixing of water masses and the info

at ITP WHOI is the only real time info I can find.  The support documents posted there are all a good
 
read.    Looks like Jim beat me to it.

Anne

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #329 on: May 20, 2015, 10:57:51 AM »
I recall reading that melt ponds are fairly stable, for when a small crack penetrates an ice floe under a melt pond, the fresh water will freeze upon reaching the cold (-1.7C) sea water (if not before), sealing the crack.
It didn't happen with the "North Pool" in 2013, though. See for example
http://forum.arctic-sea-ice.net/index.php/topic,418.msg11196.html#msg11196 (where there was discussion of melt ponds wrt CT area). Presumably the sea water temperature then was warmer than -1.7C? There must be a record somewhere, other people will know.

Is there a separate thread on sea ice melt ponds, and if not, should there be?

Anne

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #330 on: May 21, 2015, 05:33:57 AM »
Thanks, guys, I've just seen the melt ponds thread.

anotheramethyst

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #331 on: June 25, 2015, 10:34:42 AM »
can someone please help me understand this?

i know some of you prefer the temperature anonaly maps, but i have a terribly hard time understanding them.  how exactly are they calculated? like for example, do they average all the temperatures for a given location (say san antonio) and day (say christmas) over a time span (like 1980-2000).... so hypothetically maybe they come up with 37 F as an average temp for christmas in san antonio.  so is there a range thats considered "normal" before the anomaly is calculated?  like if its 40 F in san antonio on christmas is that an anomaly of + 3? and isnt that extremely normal?  or do they calculate a normal temperature range and measure an anomaly after say it falls outside of 35-40 F? 

i guess what i'm asking is how can you tell if an anomaly is normal?  weather fluctuates all the time.  how can you tell if the temperature is significantly abnormal? 

plinius

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #332 on: June 25, 2015, 10:41:31 AM »
Anomaly = simple deviation from the mean of some standard climate period. Differs from product to product, i.e. sometimes 1950-1980, 1960-90 or 1980-2010.
No. there are no "standard regions", otherwise your map would be biased as end product.
No, that would also not be sensible at all, since the dispersion of values varies.
And yes, one can tell significantly abnormal: experience, past dispersion/variance of values.

johnm33

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anotheramethyst

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #334 on: June 26, 2015, 12:13:15 AM »
awesome thanks!!!

plinius

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #335 on: June 30, 2015, 04:04:54 PM »
To add a stupid question by my side:
Lake ice vs. Sea ice & melt ponds:

From naive looking at satellite data I have the impression that lakes adjacent to sea ice show by far less water on the surface, i.e. less melt ponds.  Why exactly is that the case?

The only thing coming to my mind would be that on sea ice, the quite sweet water in the ponds contrasts with the salty ocean forced to a temperature of around -2C at the boundary. So, any cracks in sea ice get sealed by refreezing of pond water when it runs through the lower part of the ice floe, while the lake ice ponds just drain freely. Is that correct?

Paddy

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #336 on: July 04, 2015, 10:53:04 AM »
Stupid question: are the forest fires in Alaska and Canada likely to impact sea ice melt at all, and which way is most of the smoke, heat, ash etc being carried by the prevailing winds?


oren

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #338 on: July 12, 2015, 11:43:39 AM »
Has anyone seen this? Any idea about credibility (or I guess lack thereof)?

Is a mini ICE AGE on the way? Scientists warn the sun will 'go to sleep' in 2030 and could cause temperatures to plummet

http://www.dailymail.co.uk/sciencetech/article-3156594/Is-mini-ICE-AGE-way-Scientists-warn-sun-sleep-2020-cause-temperatures-plummet.html

misanthroptimist

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #339 on: July 12, 2015, 01:16:04 PM »
Has anyone seen this? Any idea about credibility (or I guess lack thereof)?

Is a mini ICE AGE on the way? Scientists warn the sun will 'go to sleep' in 2030 and could cause temperatures to plummet

http://www.dailymail.co.uk/sciencetech/article-3156594/Is-mini-ICE-AGE-way-Scientists-warn-sun-sleep-2020-cause-temperatures-plummet.html
No credibility whatsoever. https://www.skepticalscience.com/grand-solar-minimum-barely-dent-AGW.html

Wipneus

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #340 on: July 12, 2015, 01:37:44 PM »
Where do I find the exact area numbers of those regions:
https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-regional.png?attachauth=ANoY7crVzMfAIAIuf50OzbgJN9F6uC11gm087Kw92e2gLTTWpdydLAq0iwdnyQubK3n8K-8wjonWESSKKjez5HyiYz38wgKdRiSIAYbxC9qr9TsojKbPv_sVNIMc98IEi78EdK-DZ4YeJyKNfRTgUn-2kZhKBx2BIpfCdpwW3FVLf6RDzmRDfIv433GktVJz5busYeFuPdAhx275xSfS7Fe6rXQyprF1fenhypHBt_PtxUlFyKbbjW3LuxEqH3x4-9yQSbUSu5Tl&attredirects=0

Would be great to compare 2015 to 2012, especially when ignoring some regions like Baffin and Hudson


wanderer, the UH AMSR2 data exist only for 2013 and later. For 2012 I use SSMIS data that in the overlapping period is reasonable similar to the AMSR2  version.

It seems we are looking at the same thing. I have therefore a combined data set, consisting of just the Basin regions with 2012-SSMIS data, followed by the AMSR2 data. Find it here:

https://sites.google.com/site/arctischepinguin/home/amsr2/data/UH_AMSR2_3.125km_basin.areaextent.txt

(in the same directory are the full UH AMSR2 data and the Jaxa data)

Success!

seaicesailor

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #341 on: July 12, 2015, 02:20:34 PM »
Has anyone seen this? Any idea about credibility (or I guess lack thereof)?

Is a mini ICE AGE on the way? Scientists warn the sun will 'go to sleep' in 2030 and could cause temperatures to plummet

http://www.dailymail.co.uk/sciencetech/article-3156594/Is-mini-ICE-AGE-way-Scientists-warn-sun-sleep-2020-cause-temperatures-plummet.html

This paper looks likes one of those supermarket cashier magazines, an alien abducted Jenny Lo and got her pregnant, and stuff like that

pikaia

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #342 on: July 12, 2015, 03:30:33 PM »
Has anyone seen this? Any idea about credibility (or I guess lack thereof)?

Is a mini ICE AGE on the way? Scientists warn the sun will 'go to sleep' in 2030 and could cause temperatures to plummet
http://blog.hotwhopper.com/2015/07/theres-only-two-year-reprieve-if-sun.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+hotwhopper%2FSJtd+%28HotWhopper%29

"To sum up, if the sun fades over the next few years, it won't stop global warming. It will likely make a difference at the local level. In the northern hemisphere changes may be linked with changes in the North Atlantic (and possibly the Pacific)."




Jim Hunt

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #343 on: July 12, 2015, 03:56:12 PM »
Has anyone seen this? Any idea about credibility (or I guess lack thereof)?

For my views on the credibility of The Daily Mail please feel free to peruse:

http://GreatWhiteCon.info/tag/daily-mail/

Quote
The evidence suggests that David Rose doesn’t research his sources properly, doesn’t understand English and doesn’t understand common mathematical symbols.  Alternatively he understands all of that perfectly well, but chooses to misrepresent all of that to his loyal readership instead of educating them about the facts of the matter.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

oren

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #344 on: July 12, 2015, 04:14:37 PM »
Thanks all!

Jim Pettit

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #345 on: July 12, 2015, 04:31:34 PM »
Has anyone seen this? Any idea about credibility (or I guess lack thereof)?

Is a mini ICE AGE on the way? Scientists warn the sun will 'go to sleep' in 2030 and could cause temperatures to plummet

http://www.dailymail.co.uk/sciencetech/article-3156594/Is-mini-ICE-AGE-way-Scientists-warn-sun-sleep-2020-cause-temperatures-plummet.html
Here's a concatenated series of tweets from Gavin Schmidt's (@ClimateOfGavin) Twitter feed:

"A period in the late 17th C (the "Maunder minimum") had very few sunspots, smaller amplitude 11-yr cycles & perhaps reduced irradiance. Combined with an increase in volcanic activity, these natural drivers are implicated in the relative coolness of the 'Little Ice Age'. The result being discussed is a statistical prediction of a '60%' reduction in the magnitude of the next few solar cycles. For context, climate forcing over a solar cycle is about 0.175 W/m2. Current forcing from CO2 is more than 10 times larger. 60% reduction in solar cycle magnitude wld be a climate forcing of -0.1 W/m2. Equivalent to a decrease of 8ppm CO2 (~3 years worth). Thus, at max, the predicted solar cycle change will slow GW by about a few years, and has no chance of causing a 'mini ice age'."

(Bolding mine.)

DavidR

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #346 on: July 12, 2015, 04:43:07 PM »
Has anyone seen this? Any idea about credibility (or I guess lack thereof)?

Is a mini ICE AGE on the way? Scientists warn the sun will 'go to sleep' in 2030 and could cause temperatures to plummet

http://www.dailymail.co.uk/sciencetech/article-3156594/Is-mini-ICE-AGE-way-Scientists-warn-sun-sleep-2020-cause-temperatures-plummet.html
Here's a concatenated series of tweets from Gavin Schmidt's (@ClimateOfGavin) Twitter feed:

"A period in the late 17th C (the "Maunder minimum") had very few sunspots, smaller amplitude 11-yr cycles & perhaps reduced irradiance. Combined with an increase in volcanic activity, these natural drivers are implicated in the relative coolness of the 'Little Ice Age'. The result being discussed is a statistical prediction of a '60%' reduction in the magnitude of the next few solar cycles. For context, climate forcing over a solar cycle is about 0.175 W/m2. Current forcing from CO2 is more than 10 times larger. 60% reduction in solar cycle magnitude wld be a climate forcing of -0.1 W/m2. Equivalent to a decrease of 8ppm CO2 (~3 years worth). Thus, at max, the predicted solar cycle change will slow GW by about a few years, and has no chance of causing a 'mini ice age'."

(Bolding mine.)
A good way of viewing global warming is to look at the temperatures during  solar minimums. Solar maximums can increase temperatures up to about  0.3 degrees C. However these have no effect on minimums. So if you plot the minimums as a measure of increase you will see a clearly rising pattern of more than 0.1 deg centigrade per cycle. This decade has seen a low solar maximum so it is unlikely we will see a decline in temperatures as we did last decade. This decade will probably  be the first decade in recorded history with no  five year trend of declining temperatures
Toto, I've a feeling we're not in Kansas anymore

Metamemesis

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #347 on: July 13, 2015, 05:19:53 PM »
Stupid questions:

1) What resolution are the EOSDIS WorldView images?*
2) Are they better or worse than 3-5 meter resolution?
3) Would there be any interest in, or practical use use for, forum members in obtaining 3-5 meter resolution images of the Arctic Sea Ice?

* i.e. https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor%28hidden%29,MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&t=2015-07-13&v=-3595273.3764701397,-1177313.5812421292,4269046.623529861,2685214.418757871

jdallen

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #348 on: July 13, 2015, 05:26:29 PM »
Stupid questions:

1) What resolution are the EOSDIS WorldView images?*
2) Are they better or worse than 3-5 meter resolution?
3) Would there be any interest in, or practical use use for, forum members in obtaining 3-5 meter resolution images of the Arctic Sea Ice?

* i.e. https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor%28hidden%29,MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&t=2015-07-13&v=-3595273.3764701397,-1177313.5812421292,4269046.623529861,2685214.418757871

As I recall, EOSDIS Worldview minimum resolution is 250 meters.
This space for Rent.

Laurent

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #349 on: July 13, 2015, 05:37:01 PM »
I am not sure but I think Sentinel satellites have 15m resolution.
http://www.polarview.aq/arctic
But I don't think we need them so much (we, amateurs), there is the buoys to give as an idea of the quality of the ice.