Support the Arctic Sea Ice Forum and Blog

Author Topic: "Smart" and "Stupid" Questions - Feel Free To Ask  (Read 671416 times)

Shared Humanity

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2300 on: July 23, 2019, 08:34:46 PM »

Better to evaluate the CAB based on bathymetry.

Do you think there's enough contrast there?

On the Atlantic side, there are shallow ridges that extend to ~ 83N and immediately adjacent to the CAA it's also shallow, but not necessarily too relevant.

Beyond that it's deep and deeper.... a nice seque to my next stupid question:

Does it make a difference if the water is 500m deep vs 2,000m deep in terms of impact on ice melt?

Someone (not sure who) draws arbitrary lines on the Arctic Ocean and labels a portion the CAB. We then measure the amount of ice at minimum in this area and while the metric is accurate and can be compared season to season, I would argue that looking at the whole and observing the behavior of the ice relative to the actual geology, oceanography, hydrology and atmospherics would be far more useful and contribute to our understanding of what is really happening.

It has been pointed out by some here that we are seeing more and more frequent open water to the north of FJI and Svalbard and this open water parallels closely the shallow shelf that extends from the Barents. As the Barents has warmed and become more salty, the flow of this water has intruded on what use to be more ice covered than not.

I have always been fascinated by the Lomonosov Ridge which rises spectacularly from the deepest portion of the Arctic basin.

https://www.ngdc.noaa.gov/mgg/bathymetry/arctic/Images/version11024.jpg

Portions of this ridge are less than 400 meters below sea level and this ridge is curiously located near the Laptev Bite which makes its annual appearance during the melt season. What, if any impact does this ridge have on the deep ocean currents? Could this pronounced ridge cause an upwelling of warmer, saltier water from depths and result in the Laptev Bite?

As MYI has deteriorated north of the CAA, the ice seems to be separating in a more pronounced manner from the CAA during the melt season. What impact, if any, does the shallow shelf paralleling the north coast of the CAA contribute to this? If this shallow shelf is driving this phenomenon, what does this say about where the last remaining ice will hold out? We have always assumed this ice would hug the CAA but perhaps this highly fractured and mobile MYI will find itself swirling around the pole.

My problem in looking at the Arctic this way is that it only triggers questions in my mind and provides few if any answers, mere suppositions on my part, I fear.
« Last Edit: July 23, 2019, 08:42:44 PM by Shared Humanity »

AmbiValent

  • Frazil ice
  • Posts: 136
    • View Profile
  • Liked: 7
  • Likes Given: 0
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2301 on: July 24, 2019, 11:36:52 AM »
Is there a warm current going north just west of Svalbard, and if so, what happens to this water when it melts ice and cools? (Would it sink to deeper layers?)
Bright ice, how can you crack and fail? How can the ice that seemed so mighty suddenly seem so frail?

DrTskoul

  • Nilas ice
  • Posts: 1454
    • View Profile
  • Liked: 211
  • Likes Given: 60
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2302 on: July 24, 2019, 12:33:48 PM »
Is there a warm current going north just west of Svalbard, and if so, what happens to this water when it melts ice and cools? (Would it sink to deeper layers?)

From Mercator the temperature map around Svalbard shows that any warm current and water is more saline and it would sink under the colder less saline water with mixing at the interface between layers. Below are images of temperature and salinity at 0 and 30 m.




oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2303 on: July 24, 2019, 12:52:54 PM »
Is there a warm current going north just west of Svalbard, and if so, what happens to this water when it melts ice and cools? (Would it sink to deeper layers?)
There is such a current indeed, and answers can be found in the very detailed Wikipedia page.
https://en.wikipedia.org/wiki/West_Spitsbergen_Current
Quote
After the WSC splits off from the Norwegian Atlantic Current it begins to enter very cold atmospheric conditions. The cold atmosphere is able to cool the surface water, and in some instances this water cools so much that some of the WSC water actually sinks due to its density increase, all the while holding its salinity constant. This is one element of the formation of the Lower Arctic Intermediate Water.[3] As the current continues to move northward and reaches the continental shelf of western Svalbard it begins to encounter sea-ice. The sea-ice melts due to the warmth of the WSC, and thus a surface layer of very freshwater begins to exist. Winds mix the freshwater and the warm salty water of the WSC mix, creating some Arctic Surface Water. This Arctic Surface Water is now less dense than the Atlantic Water in the WSC and thus the WSC begins to sink underneath the Arctic Surface Water. At this point the WSC is still relatively warm and very saline. Thus, this allows the Atlantic Water in the WSC to be completely isolated from the surface waters.

Note Spitzbergen is the name of the largest island in the Svalbard archipelago.

nanning

  • Nilas ice
  • Posts: 2376
  • 0Kg CO₂, 37 KWh/wk,125L H₂O/wk, No offspring
    • View Profile
  • Liked: 294
  • Likes Given: 20108
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2304 on: July 24, 2019, 06:40:06 PM »
Sorry, a strange and possibly very stupid question:
When I want to increase the waterstream from my tap, I turn it to the left. When I want to increase the electronstream in my amplifier, I turn it to the right. Does anyone why that is?
"It is preoccupation with possessions, more than anything else, that prevents us from living freely and nobly" - Bertrand Russell
"It is preoccupation with what other people from your groups think of you, that prevents you from living freely and nobly" - Nanning
Why do you keep accumulating stuff?

pleun

  • New ice
  • Posts: 59
    • View Profile
  • Liked: 25
  • Likes Given: 6
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2305 on: July 24, 2019, 06:50:19 PM »

Note Spitzbergen is the name of the largest island in the Svalbard archipelago.

It is spitsbergen in dutch or jagged mountains.
(spitzen are ballet shoes). which  brings me to my own stupid question:

why does the dutch word ijsberg translate to iceberg while a regular "berg" (made out of rock) is a mountain or hill ?


RoxTheGeologist

  • Grease ice
  • Posts: 521
    • View Profile
  • Liked: 153
  • Likes Given: 126
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2306 on: July 24, 2019, 06:54:07 PM »
Here's a more informative way to look at the central Arctic - a sea surface height map. There are strong SSH gradients across the central Arctic indicating strong flow of water and ice. This year the transpolar drift has been strong and has run right through the central Arctic. The areas in the central Arctic basin with high SSH store fresh water and the areas with low SSH are dominated by cold salty water.

FOW - When you say store, wouldn't the density difference in the water column mean that the freshwater flows from high to low areas? I assume (probably incorrectly) that the elevated SSH topography is dynamic, that the pool of freshwater is continually replenished (say, though river input) and mixes and disperses unless there is some external force (such as the BG) that creates a physical force to maintain the hydrostatic imbalance.


oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2307 on: July 24, 2019, 07:00:09 PM »
why does the dutch word ijsberg translate to iceberg while a regular "berg" (made out of rock) is a mountain or hill ?
Because iceberg is an ice mountain in all Germanic languages. Assuming I understood the question correctly.
Wiktionary has a little more info to add, which could be the answer you seek:
Quote
Borrowed from Dutch ijsberg, compound of ijs (“ice”) + berg (“mountain”). First used to describe a glacier as seen at a distance from a ship then used as a term to describe the floating chunks of ice broken off from such glaciers. Compare German Eisberg, Danish isbjerg, Norwegian/Swedish isberg.

oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2308 on: July 24, 2019, 07:06:45 PM »
Sorry, a strange and possibly very stupid question:
When I want to increase the waterstream from my tap, I turn it to the left. When I want to increase the electronstream in my amplifier, I turn it to the right. Does anyone why that is?
You are not the first one to pose the question, and the answer is not immediately apparent when googling. But here's some explanation I found:
Quote
The purpose of a tap is to place a constriction on the flow - remove the tap and water/gas would just gush out the pipe. Turning clockwise increases the effect of the device. An amplifier makes an electrical signal greater - no amplifier, and the signal would be too small to make an audible sound. Turning clockwise increase the effect of the device. Same model.
The way I see it, a tap is a screw and you unscrew to the "left" (anti-clockwise to be accurate). So this was easy to decide.
The amplifier came later, and I'm not sure what was the design principle the inventor came up with to make it increase clockwise.

nanning

  • Nilas ice
  • Posts: 2376
  • 0Kg CO₂, 37 KWh/wk,125L H₂O/wk, No offspring
    • View Profile
  • Liked: 294
  • Likes Given: 20108
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2309 on: July 24, 2019, 07:12:55 PM »
Thank you oren :)
"It is preoccupation with possessions, more than anything else, that prevents us from living freely and nobly" - Bertrand Russell
"It is preoccupation with what other people from your groups think of you, that prevents you from living freely and nobly" - Nanning
Why do you keep accumulating stuff?

HapHazard

  • Frazil ice
  • Posts: 367
    • View Profile
  • Liked: 144
  • Likes Given: 2680
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2310 on: July 24, 2019, 07:17:57 PM »
When I want to increase the electronstream in my amplifier, I turn it to the right. Does anyone why that is?
You have to turn the amplifier to the right in order to reach eleven.

pleun

  • New ice
  • Posts: 59
    • View Profile
  • Liked: 25
  • Likes Given: 6
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2311 on: July 24, 2019, 07:30:27 PM »
no no, you hold the knob fixed and turn the amplifier to the left. so it's the same as the tap again.
see ?

Sterks

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2312 on: July 24, 2019, 07:36:56 PM »
When I want to increase the electronstream in my amplifier, I turn it to the right. Does anyone why that is?
You have to turn the amplifier to the right in order to reach eleven.
Indeed

gerontocrat

  • First-year ice
  • Posts: 9311
    • View Profile
  • Liked: 3718
  • Likes Given: 28
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2313 on: July 24, 2019, 09:21:18 PM »
I reckon the amplifier guy was a lefty,

or,

he had just changed the cylinder on his camping gas stove. That has a left-handed thread (at least in the UK)
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

philopek

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2314 on: July 24, 2019, 09:30:34 PM »
Thank you oren :)

I'm not sure whether you're kidding or this is serious.

Either way there is no problem at all to produce a tap and an amplifier that work the other way around, exactly like driving left or right on a road is a choice, those are choices that initially often were different by constructors and were standardized/unified a given moment in time due to compatibility issues, safety and accidents, depending on the technology at hand.

Not long ago and perhaps some still exist, there were countries where screws were turned in and out the opposite way.

Another example would be gear boxex that would work the opposite way on motorcycles, instead of 1st down rest up, they had 1st up and rest down layouts.

One example where both were applied were Moto Guzzi Italian motorcycles and and in parts, Ducati motorcycles, both Italian brands.

Story could be continued with an endless number of examples, what i want to say is that
the assumption that those are kind of natural layouts is not correct.


Tor Bejnar

  • Young ice
  • Posts: 3634
    • View Profile
  • Liked: 633
  • Likes Given: 406
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2315 on: July 24, 2019, 09:40:11 PM »
no no, you hold the knob fixed and turn the amplifier to the left. so it's the same as the tap again.
see ?
I like standing behind the amp, reach around, and turn the knob to the left. :D
Arctic ice is healthy for children and other living things.

Bugalugs

  • New ice
  • Posts: 45
    • View Profile
  • Liked: 16
  • Likes Given: 10
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2316 on: July 24, 2019, 09:56:37 PM »
Now we know why the drummer went in a green flash, it was the guitarist meddling with his amp.

Sterks

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2317 on: July 24, 2019, 11:21:36 PM »
I reckon the amplifier guy was a lefty,

or,

he had just changed the cylinder on his camping gas stove. That has a left-handed thread (at least in the UK)
Yeah, lefty was a guitarist, famous for cranking up ALL the marshall knobs to 11 ( volume drive hi lows mids ) before each concert, but it was a urban legend (I think)

Rich

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2318 on: July 25, 2019, 04:17:45 AM »
I'm back !

I'm looking the current GFS 10 day MAX 2M temp forecast. It's nicely color coded for low IQ folks like me.

In the center of the map, very close to 90N is a big chunk of real estate that's forecast to hit 3C.

It's surrounded by area that is only forecast to reach 2C.

Some of the very smart people on the melting season thread are telling me that the presence of ice limits the temperature to near freezing. If that's the case, how is the North Pole hitting 3C?

Other smart people say there is an exception for warm air advection from land. But there isn't any land near 90N.

Which factors determine the 2M temperature at 90N?

DrTskoul

  • Nilas ice
  • Posts: 1454
    • View Profile
  • Liked: 211
  • Likes Given: 60
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2319 on: July 25, 2019, 04:36:05 AM »
The 2m temperature is an interpolated model result, not a real model grid point. As such, it can be overestimated or underestimated depending the heat transfer coefficient assumed at surface. For example during winter if fresh snow falls over old snow, providing more insulation,  the real 2m temp might be smaller than model. There are situations that the opposite might occur , where heat transfer to ice is larger than reality.
« Last Edit: July 25, 2019, 04:42:20 AM by DrTskoul »

binntho

  • Nilas ice
  • Posts: 1519
    • View Profile
  • Liked: 528
  • Likes Given: 118
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2320 on: July 25, 2019, 04:37:22 AM »
why does the dutch word ijsberg translate to iceberg while a regular "berg" (made out of rock) is a mountain or hill ?
Because iceberg is an ice mountain in all Germanic languages. Assuming I understood the question correctly.
Wiktionary has a little more info to add, which could be the answer you seek:
Quote
Borrowed from Dutch ijsberg, compound of ijs (“ice”) + berg (“mountain”). First used to describe a glacier as seen at a distance from a ship then used as a term to describe the floating chunks of ice broken off from such glaciers. Compare German Eisberg, Danish isbjerg, Norwegian/Swedish isberg.

Doesn't sound right. The first glaciers that Germanic speaking peoples would see would be Alpine glaciers followed by Norwegian glaciers.

It's only when they start sailing to Iceland some 1200 years ago that they would be likely to see glaciers rising from the sea, as well as significant amounts of floating ice. Greenland was reached by Germanic speaking peoples 1000 years ago

In Icelandic, a glacier is "jökull" (pronounced somewhat like "yocudl") and ice floating in water is "jaki". Both words are more or less the same in Old Norse and Old Germanic, and probably share their origin with the English "glacier", German "gletscher" and the Italian "ghiacciaio".

A very large iceberg is called, in Icelandic, "borgarísjaki" which might translate as a "floating ice looking like a large cliff".

The Dutch "ijsberg" and the Danish "isberg" is more probably translated as "ice cliff" than "ice mountain", even if both Dutch and Danish today use the word "berg" or "bjerg" for mountain, probably because they don't have any and can't tell the difference.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

Michael Hauber

  • Grease ice
  • Posts: 900
    • View Profile
  • Liked: 77
  • Likes Given: 14
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2321 on: July 25, 2019, 05:10:29 AM »
I'm back !

I'm looking the current GFS 10 day MAX 2M temp forecast. It's nicely color coded for low IQ folks like me.

In the center of the map, very close to 90N is a big chunk of real estate that's forecast to hit 3C.

It's surrounded by area that is only forecast to reach 2C.

Some of the very smart people on the melting season thread are telling me that the presence of ice limits the temperature to near freezing. If that's the case, how is the North Pole hitting 3C?

Other smart people say there is an exception for warm air advection from land. But there isn't any land near 90N.

Which factors determine the 2M temperature at 90N?

Relatively warm air is being advected at mid and higher levels of the atmosphere.  This air is then pushed down towards the surface of the ice as high pressure = sinking air.  This effect is strongest towards the center of the high pressure, so no surprise to me that greater surface warmth forecast in the middle.  Forecasts also suggest a bubble of warm air being pinched off from near Alaska and moving towards the pole.  Current forecasts suggest temps at 850hp peaking over 4 deg C near the pole.  Air will very roughly warm by about 10 C if forced down from 850hp to the surface, and so this is roughly equivalent to 14 C at the surface.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

binntho

  • Nilas ice
  • Posts: 1519
    • View Profile
  • Liked: 528
  • Likes Given: 118
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2322 on: July 25, 2019, 05:10:44 AM »
I'm back !

I'm looking the current GFS 10 day MAX 2M temp forecast. It's nicely color coded for low IQ folks like me.

In the center of the map, very close to 90N is a big chunk of real estate that's forecast to hit 3C.

It's surrounded by area that is only forecast to reach 2C.

Some of the very smart people on the melting season thread are telling me that the presence of ice limits the temperature to near freezing. If that's the case, how is the North Pole hitting 3C?

Other smart people say there is an exception for warm air advection from land. But there isn't any land near 90N.

Which factors determine the 2M temperature at 90N?
Ok, here my take as a total amateur:

To begin with, let's think about why meteorologists use 2M temparatures, and not surface temparatures. The simple answer is: 2M temparatures are more correct when it comes to weather because they are not as influenced by the state of the surface.

If there is ice, then the air temperature at the surface will always tend to 0 degres C. In still air, it is very possible to have several degrees higher temparatures at 2M, with the colder surface air staying at the surface, with very little heat transfer downwards.

But if there is any wind then the air keeps getting mixed up, with warmer air hitting the ground and colder air being swept up. If the air being blown in by the wind is warm enough, then you might still see the same temperature profile as in very still air, with near 0 at the surface and 2 -3 at 2M.

You have to remember that wind does not only flow along the ground, but very often is flowing down or up depending on weather systems such as fronts, highs and lows. So a warm downwelling wind with turbulence at the surface could quite happily maintain a profile of 0 degrees at the ice surface, 2 or 3 at 2 meters and higher temps at higher altitudes.

So looking at temperatures only tells you a very limited part of what is actually happening. Is the air moving, how is it moving, what is the temperature of the air being brought into the system along the surface and / or from higher up?

And then you have to look at humidity and dew point as well if you want to get a grasp of whether the ice is melting or not. If relatively warm and humid air is being transported in over the Arctic and flushed downward, then the water vapor will condense on the ice, releasing significant amounts of energy that goes into melting the ice - without changing the average temperatures at all!

Take a look at the Arctic in Nullschool today. You will see winds "starting" over Beaufort and "ending" over Laptev. This is because over the Beaufort, air is sinking, while over the Laptev the air is rising. If the air that is sinking over the Beaufort is warm and moist, then a hell of a lot of melt can happen there, even with a temperature of only 2 or 3 at 2M.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

DrTskoul

  • Nilas ice
  • Posts: 1454
    • View Profile
  • Liked: 211
  • Likes Given: 60
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2323 on: July 25, 2019, 05:26:01 AM »
2m temperatures are used because that is the height ( 1.5-2m ) of Stevenson screens. Everywhere away from land the 2m is a model interpolation. The 2m has nothing to do with turbulence,  " weather" etc. It is the height of Stevenson screens.

Read here: https://confluence.ecmwf.int/plugins/servlet/mobile?contentId=131397409#content/view/131397409

binntho

  • Nilas ice
  • Posts: 1519
    • View Profile
  • Liked: 528
  • Likes Given: 118
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2324 on: July 25, 2019, 05:32:07 AM »
2m temperatures are used because that is the height ( 1.5-2m ) of Stevenson screens. Everywhere away from land the 2m is a model interpolation. The 2m has nothing to do with turbulence,  " weather" etc. It is the height of Stevenson screens.

Read here: https://confluence.ecmwf.int/plugins/servlet/mobile?contentId=131397409#content/view/131397409
Thanks for the early morning laugh! I wonder why they build the screens that way?

From weatheronline.co.uk
Quote
It is kept 1.25m/4.1ft (UK standard) above the ground by legs to avoid strong temperature gradients at ground level ...
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

DrTskoul

  • Nilas ice
  • Posts: 1454
    • View Profile
  • Liked: 211
  • Likes Given: 60
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2325 on: July 25, 2019, 05:54:16 AM »
So it is not heated or cooled by the ground during the course of a day....again nothing  to do with atmospheric turbulence or weather.

binntho

  • Nilas ice
  • Posts: 1519
    • View Profile
  • Liked: 528
  • Likes Given: 118
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2326 on: July 25, 2019, 05:59:31 AM »
So it is not heated or cooled by the ground during the course of a day....again nothing  to do with atmospheric turbulence or weather.
Yes - well wasn't that what I was saying? We talk about 2m temparatures because we do not want to be confused by surface temparatures.

"Weather" is what hits us in the face (at 2m quite a bit above my head actually) and affects the biosphere. So that's why meteorologists aren't predicting ground temparatures or 850 geopontential temparatures (although they of course are part of the whole package) and also why they don't use ground temperatures or 850 geopontial temparatures when they describe the weather.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

kassy

  • Nilas ice
  • Posts: 2457
    • View Profile
  • Liked: 1174
  • Likes Given: 1020
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2327 on: July 25, 2019, 10:23:54 AM »
why does the dutch word ijsberg translate to iceberg while a regular "berg" (made out of rock) is a mountain or hill ?

Mountain derives from old French and ofc we do not have real mountains so when we talk about the ´bergen in the alpen´ we talk about their montagne/mountains.

We did have a lot of ship so somehow the iceberg is derived from dutch but the word root is similar for danish and norwegian so basically it is derived from that language group  in about the 19th century. (It would be cool if we had an online database where we could jump to the actual articles and books the word starts appearing in at the time, or at least a list of names of those and the authors).

https://www.etymonline.com/word/iceberg

BTW no one would translate it as ´klif´ but that is because we lump all that exotic stuff. Van de Berg is a common dutch name so we use it for small humps.
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

DrTskoul

  • Nilas ice
  • Posts: 1454
    • View Profile
  • Liked: 211
  • Likes Given: 60
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2328 on: July 25, 2019, 11:55:53 AM »
And iceberg sounds so much cooler than ice mountain....

Tor Bejnar

  • Young ice
  • Posts: 3634
    • View Profile
  • Liked: 633
  • Likes Given: 406
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2329 on: July 25, 2019, 04:12:24 PM »
Quote
It would be cool if we had an online database where we could jump to the actual articles and books the word starts appearing in at the time, or at least a list of names of those and the authors
Google Ngrams yields "1746" as the first use of the word "iceberg" in an English language book, and it 'took off' in 1813 or 14. (but, alas, no list of books or authors)
Arctic ice is healthy for children and other living things.

UCMiami

  • Frazil ice
  • Posts: 128
    • View Profile
  • Liked: 92
  • Likes Given: 109
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2330 on: July 25, 2019, 05:51:20 PM »
What I am interested in doing is understanding the monolith known as the CAB and subdividing it to better understand it.

The divisions you suggested seem very logical.

I'll give you an example of what I was imagining in the way of analysis....
Thanks for the feedback.
I managed to find the crude map I was referring to, and the post from last year in which I explained the logic behind it. Looking back on it, the Pacific CAB sector should probably be a bit thicker.
The big challenge is once someone adopts this map, there is not much one can do in terms of quantitative analysis (such as area per sub-region, volume per sub-region), unless one can do the number-crunching of taking the gridded data files and filtering them by sub-region according to the new demarcations. That I have not been able to do, though it's theoretically possible (I can program crudely, have a PC, and don't dislike number crunching). An attention deficit issue coupled with lack of time I suspect.
Oren - just a simple question - if we are to create a new arctic sea definition, why not just redefine the current seas around the CAB with a boundary more northerly rather than create a new set of arbitrary seas in the southern CAB? The southern boarder of the CAB is already arbitrary and there are two current definitions in frequent use. And the the seas around the CAB are frequently becoming ice free/irrelevant by the late melt season and their area and extent during the melt season is dominated by import of cab ice south or export their ice north into the CAB.

Seems to me the more artificial boundaries we create, the more artificial the measurements of those individual seas becomes - a new 'north/south' border does not create more of these boundaries, just redefines the ones we have already created.

Rich

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2331 on: July 25, 2019, 07:08:52 PM »

Oren - just a simple question - if we are to create a new arctic sea definition, why not just redefine the current seas around the CAB with a boundary more northerly rather than create a new set of arbitrary seas in the southern CAB?

For what it's worth, I kinda like this suggestion.

Defining the respective seas as continuing to 90N would be useful.

Then you wind up with a much smaller CAB like entity N. of Greenland / Ellesmere 

Of course, it would confuse the hell out of lots of people.

Memshin

  • New ice
  • Posts: 2
    • View Profile
  • Liked: 1
  • Likes Given: 3
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2332 on: July 25, 2019, 07:19:01 PM »
My first post, after lurking for several years! I am not a scientist, but read quite a bit of science in my spare time. This includes reading (and re-reading) large sections of the blog "Science of Doom" to try to familiarize myself with the basics of climate science.
I recently Googled "climate science for dummies" and one of the top results was this: https://sciencetrends.com/climate-change-dummies-basics-climate-change-physics/
The author claims that it is the 'specific heat' of various molecules that determines their green house gas property. This is quite different from what I've read elsewhere, which is that it is the ability of different molecules to absorb and re-emit long wave radiation that is important.
My question is: is there an additional role for specific heat in the dynamics of global heating, or is this author simply mistaken? (He does not seem from the article to be a denier, but might still just be misinformed)

oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2333 on: July 26, 2019, 04:15:39 AM »
Quote
I managed to find the crude map I was referring to, and the post from last year in which I explained the logic behind it. Looking back on it, the Pacific CAB sector should probably be a bit thicker.
Oren - just a simple question - if we are to create a new arctic sea definition, why not just redefine the current seas around the CAB with a boundary more northerly rather than create a new set of arbitrary seas in the southern CAB? The southern boarder of the CAB is already arbitrary and there are two current definitions in frequent use. And the the seas around the CAB are frequently becoming ice free/irrelevant by the late melt season and their area and extent during the melt season is dominated by import of cab ice south or export their ice north into the CAB.

Seems to me the more artificial boundaries we create, the more artificial the measurements of those individual seas becomes - a new 'north/south' border does not create more of these boundaries, just redefines the ones we have already created.
I am not a weather person, but really a numbers person. I like to try and tease out proof of the trends from the data. The bigger the geographic regions, and the more diverse their internal composition, the worse it is for data analysis.
You may recall the "Weatherdude88" posting how the CAB was higher this year compared to all other years. While technically correct, the only reason for that was the area around Svalbard which is very different from the rest of the CAB, and is dependent on the direction of general drift in the Arctic in a given year.
So the NSIDC lumps together the Chukchi with a northern region which does not geographically behave like the Chukchi, same for the Beaufort, ESS and Laptev. CT/Wipneus right-sizes the adjacent seas, but makes the CAB huge. and both include "north of Svalbard" in the CAB.
So I prefer the CT/Wipneus version of the adjacent seas, but prefer a smaller and well partitioned CAB. All boundaries are somewhat arbitrary but still geography and data statistics/behavior can dictate reasonable answers.

My dream is to generate statistics for any given specific grid point - how does its volume behave over time, how did the chances of it being ice-free on a given date change over the years, and more. But for that I would have to be able to analyze and compute the gridded data files.

Rich

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2334 on: July 26, 2019, 05:39:02 AM »
I'm not sure if the data exists, but I would love to see a score for each grid point based upon depth and distance from continental land mass. 

These seem to be the factors most correlated with whether ice remains at end of season.

It might be fun to attend an NSIDC open house and talk to the analytical folks there to ask questions and better understand the parameters of their datasets.


UCMiami

  • Frazil ice
  • Posts: 128
    • View Profile
  • Liked: 92
  • Likes Given: 109
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2335 on: July 26, 2019, 07:15:39 PM »
Oren - thanks for the further explanation. I understand more what you are describing.

I like the current NSIDC definitions because they are mostly tied to specific geological boundaries (except for the northern definition) and they prove to be fairly consistent in their yearly melt profiles - the inconsistencies being pretty clearly tied to significant arctic wide yearly variations. Moving the boundaries further north I think would not significantly alter their characteristics and keep the seas anchored to the respective continental land masses. With the continued trend of lower minima more northerly boundaries would reflect the changing environment as well.

With more un-anchored sea definitions dividing the current CAB I can imagine years where the data during melt season would be wildly different, not because of actual melting, but because of less than significant shifts in the arctic ice pack. While this would be obvious to scientists and amateurs who actually focus on the topic, the more casual observers would likely misinterpret and misrepresent those kinds of variations, some with less than honest intentions.

NB: I am not suggesting the northern border be shifted to 90N, but perhaps 85N or something like that. Deciding how to assign the area north of Greenland and the CAA would be debatable - perhaps either 30W or the Nares being the demarcation between Greenland and CAA? Or just leaving the area N of the CAA/Greenland as part of the CAB? making the CAB more ovoid since this area has more characteristics of the CAB than of a peripheral sea at this time.

Rich

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2336 on: July 27, 2019, 08:13:30 PM »
If anyone is interested in teaching, I have a question.

Let's say we have a high pressure system over the Arctic and the 2M temperature is 3C right over the pole from 85-90N. In the 80-85N ice covered ring around the pole is 2C. The rest of the ice covered Arctic is 1C.

Is there any relationship between the temperature over the ice and melt rate of the ice beneath it?

Will the 90N ice melt at the same rate as the 80N ice?

Sterks

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2337 on: July 27, 2019, 09:22:24 PM »
If anyone is interested in teaching, I have a question.

Let's say we have a high pressure system over the Arctic and the 2M temperature is 3C right over the pole from 85-90N. In the 80-85N ice covered ring around the pole is 2C. The rest of the ice covered Arctic is 1C.

Is there any relationship between the temperature over the ice and melt rate of the ice beneath it?

Will the 90N ice melt at the same rate as the 80N ice?
One thing is that the surface temperature over multi year ice typically found at central CAB (at least 2 years old), with the pack closed, no open water, is 0C
The surface temperature on open polynya, on the marginal ice zones at the edge of the pack where theres plenty of open water between the ice drops to -1.8 to -1.5 C over the water (freeze point for salty sea water).

Now the 2m temp will be 1, 2, 3 or 5 deg above if there are warm winds aloft, and strong high pressure forcing air to sink and compressing it which means temps up by shear wind and by subsidence.

In The Netherlands the other night they experienced this subsidence, almost warmer at night than afternoon (40 deg C)

oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2338 on: July 27, 2019, 09:32:17 PM »
I am not a weather expert but my understanding is that melting is much more affected by winds and humidity and by water temperature and ice movement than by plain air temperatures.
If the air is static it will not melt much ice, if the air is moving it will melt much more ice.
In both cases, air temp could be the same, but the energy imparted to the ice is much different. And the air temp you see is after that energy has been imparted, so tells you less than what you may think it tells you.
Try it at home, put some ice next to a fan and the same size ice away from the fan, see which melts first.

Capt Kiwi

  • New ice
  • Posts: 18
    • View Profile
  • Liked: 5
  • Likes Given: 21
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2339 on: July 27, 2019, 09:41:39 PM »
Good morning and thank you in advance for any time you might take in replying to my spectacularly and almost incoherently stupid question!
Would anybody be able to tell me what the current consensus is on the degree of global dimming we currently have? My understanding was that it was somewhere between .8c and 1.2c but somebody in the 2019 melting thread said that it is now considered to be much lower than previously thought.
Cheers!

oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2340 on: July 27, 2019, 09:49:01 PM »
It's not a stupid question at all but here's my somewhat stupid answer.
There is no consensus. Hyper-alarmists say stuff like 4C, which I think is BS, but what the real number is whether 0.5C or 1 C or 1.5C I do not know.
IIRC the recent mention was that the effect is stronger than previously thought, not weaker.
Not much help I know...

Steerpike

  • New ice
  • Posts: 15
    • View Profile
  • Liked: 11
  • Likes Given: 23
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2341 on: July 27, 2019, 09:54:04 PM »
I am not a weather expert but my understanding is that melting is much more affected by winds and humidity and by water temperature and ice movement than by plain air temperatures.
If the air is static it will not melt much ice, if the air is moving it will melt much more ice.
In both cases, air temp could be the same, but the energy imparted to the ice is much different. And the air temp you see is after that energy has been imparted, so tells you less than what you may think it tells you.
Try it at home, put some ice next to a fan and the same size ice away from the fan, see which melts first.

Absolutely. It's energy transfer that melts the ice in all cases, and still air at any (reasonable) temperature won't melt much ice. However, air blowing over ice cools down rapidly as it does melt the ice. That's why the central Arctic ice remains so well protected (and, coupled with a very short period of high insolation, ice becomes thicker and is very hard to remove). On the other hand, often continual hot air starts blowing off the land once the land snow melts in early summer onto peripheral seas, melting them fast. Subsidence is more important if high pressure builds over the high Arctic (though air speed won't be great), but probably the biggest  ice killer there, when it happens, is condensation from moist air.

philopek

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2342 on: July 27, 2019, 10:07:36 PM »
Absolutely. It's energy transfer that melts the ice in all cases, and still air at any (reasonable) temperature won't melt much ice. However, air blowing over ice cools down rapidly as it does melt the ice. That's why the central Arctic ice remains so well protected (and, coupled with a very short period of high insolation, ice becomes thicker and is very hard to remove).

I agree while we should not forget that ice in the CAB is mostly removed through export/movement.

Shared Humanity

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2343 on: July 27, 2019, 10:16:35 PM »
Absolutely. It's energy transfer that melts the ice in all cases, and still air at any (reasonable) temperature won't melt much ice. However, air blowing over ice cools down rapidly as it does melt the ice. That's why the central Arctic ice remains so well protected (and, coupled with a very short period of high insolation, ice becomes thicker and is very hard to remove).

I agree while we should not forget that ice in the CAB is mostly removed through export/movement.

Not sure I agree with this and I'm certain I haven't a clue how to quantify insitu melting in the CAB and export.

Steerpike

  • New ice
  • Posts: 15
    • View Profile
  • Liked: 11
  • Likes Given: 23
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2344 on: July 27, 2019, 10:18:31 PM »
Absolutely. It's energy transfer that melts the ice in all cases, and still air at any (reasonable) temperature won't melt much ice. However, air blowing over ice cools down rapidly as it does melt the ice. That's why the central Arctic ice remains so well protected (and, coupled with a very short period of high insolation, ice becomes thicker and is very hard to remove).

I agree while we should not forget that ice in the CAB is mostly removed through export/movement.

Very true, and why it's most in danger from continual thinning - the reason extent is high on the Atlantic side this year is it's more fragile and mobile.

Steerpike

  • New ice
  • Posts: 15
    • View Profile
  • Liked: 11
  • Likes Given: 23
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2345 on: July 27, 2019, 10:21:22 PM »
Absolutely. It's energy transfer that melts the ice in all cases, and still air at any (reasonable) temperature won't melt much ice. However, air blowing over ice cools down rapidly as it does melt the ice. That's why the central Arctic ice remains so well protected (and, coupled with a very short period of high insolation, ice becomes thicker and is very hard to remove).

I agree while we should not forget that ice in the CAB is mostly removed through export/movement.

Not sure I agree with this and I'm certain I haven't a clue how to quantify insitu melting in the CAB and export.

I suppose the big unknown is how much bottom melt is going on. All other inputs are minimised by how well it's protected. Even high pressure subsidence is minimised by temperature inversions that occur over a cold surface.

philopek

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2346 on: July 27, 2019, 10:28:15 PM »
Absolutely. It's energy transfer that melts the ice in all cases, and still air at any (reasonable) temperature won't melt much ice. However, air blowing over ice cools down rapidly as it does melt the ice. That's why the central Arctic ice remains so well protected (and, coupled with a very short period of high insolation, ice becomes thicker and is very hard to remove).

I agree while we should not forget that ice in the CAB is mostly removed through export/movement.

Not sure I agree with this and I'm certain I haven't a clue how to quantify insitu melting in the CAB and export.

No problem, we gonna find out one day, looking forward to it, perhaps someone has numbers ready that i don't have.

Looking at ice movement i had the impression that the ice is transiting the polar region, some out of Fram and the reminder to Beaufort via lurking north of CAA for some time that is getting shorter by the year due to mobility and fragmentation.

However that may be, I'm open to input for better assessment, thanks for  the kind reply.
« Last Edit: July 27, 2019, 10:53:17 PM by philopek »

Rich

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2347 on: July 27, 2019, 10:51:50 PM »
If anyone is interested in teaching, I have a question.

Let's say we have a high pressure system over the Arctic and the 2M temperature is 3C right over the pole from 85-90N. In the 80-85N ice covered ring around the pole is 2C. The rest of the ice covered Arctic is 1C.

Is there any relationship between the temperature over the ice and melt rate of the ice beneath it?

Will the 90N ice melt at the same rate as the 80N ice?
One thing is that the surface temperature over multi year ice typically found at central CAB (at least 2 years old), with the pack closed, no open water, is 0C
The surface temperature on open polynya, on the marginal ice zones at the edge of the pack where theres plenty of open water between the ice drops to -1.8 to -1.5 C over the water (freeze point for salty sea water).

Now the 2m temp will be 1, 2, 3 or 5 deg above if there are warm winds aloft, and strong high pressure forcing air to sink and compressing it which means temps up by shear wind and by subsidence.

In The Netherlands the other night they experienced this subsidence, almost warmer at night than afternoon (40 deg C)

Thanks for the try Sterks.

I asked the question the way I did (with warmer air at the pole) because I see this configuration occasionally and requires an explanation beyond what has been offered previously.

Others have suggestion warm air advection from land as a source of heat over the ice. That makes sense, but it doesn't fully explain those unusual situations where it gets warmer to the pole. How does that work?

Anyhow, the question of the temperature of the air over the ice remains. Is it not relevant?

I have a question to a smart person on this via e-mail as well. We'll see what turns up.

Capt Kiwi

  • New ice
  • Posts: 18
    • View Profile
  • Liked: 5
  • Likes Given: 21
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2348 on: July 27, 2019, 10:56:39 PM »
It's not a stupid question at all but here's my somewhat stupid answer.
There is no consensus. Hyper-alarmists say stuff like 4C, which I think is BS, but what the real number is whether 0.5C or 1 C or 1.5C I do not know.
IIRC the recent mention was that the effect is stronger than previously thought, not weaker.
Not much help I know...
Cheers Oren! Actually a solid and very helpful reply thank you!
(Surely the scariest number in the world right now!?)

philopek

  • Guest
Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #2349 on: July 27, 2019, 10:57:20 PM »
If anyone is interested in teaching, I have a question.

Let's say we have a high pressure system over the Arctic and the 2M temperature is 3C right over the pole from 85-90N. In the 80-85N ice covered ring around the pole is 2C. The rest of the ice covered Arctic is 1C.

Is there any relationship between the temperature over the ice and melt rate of the ice beneath it?

Will the 90N ice melt at the same rate as the 80N ice?
One thing is that the surface temperature over multi year ice typically found at central CAB (at least 2 years old), with the pack closed, no open water, is 0C
The surface temperature on open polynya, on the marginal ice zones at the edge of the pack where theres plenty of open water between the ice drops to -1.8 to -1.5 C over the water (freeze point for salty sea water).

Now the 2m temp will be 1, 2, 3 or 5 deg above if there are warm winds aloft, and strong high pressure forcing air to sink and compressing it which means temps up by shear wind and by subsidence.

In The Netherlands the other night they experienced this subsidence, almost warmer at night than afternoon (40 deg C)

Thanks for the try Sterks.

I asked the question the way I did (with warmer air at the pole) because I see this configuration occasionally and requires an explanation beyond what has been offered previously.

Others have suggestion warm air advection from land as a source of heat over the ice. That makes sense, but it doesn't fully explain those unusual situations where it gets warmer to the pole. How does that work?

Anyhow, the question of the temperature of the air over the ice remains. Is it not relevant?

I have a question to a smart person on this via e-mail as well. We'll see what turns up.

There remains those events when warm air is intruding up from the Atlantic, originating in the Gufl of Mexico.

This phenomenon is best visible in winter, i.e. 0C in January at the pole, even though only briefly but clearly visible as a tongue of warmth protruding into the CAB.

The same thing can happen in summer as well, it's just not so obvious when the surroundings are not 40 below 0 but around zero as well.