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Author Topic: "Smart" and "Stupid" Questions - Feel Free To Ask  (Read 642542 times)

Peter Ellis

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Re: Stupid Questions :o
« Reply #350 on: July 13, 2015, 05:47:52 PM »
Interest?  Probably.
Practical use for?  Minimal.
Ability to obtain?  Non-existant.

ktonine

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Re: Stupid Questions :o
« Reply #351 on: July 13, 2015, 06:00:23 PM »
Interest?  Probably.
Practical use for?  Minimal.
Ability to obtain?  Non-existant.

Peter, non-existant? Naw, you're just getting old :)

The current commercial satellite packages offer resolutions of less than .5m. 

See wikipedia for a quick rundown of what's availavble.  https://en.wikipedia.org/wiki/Satellite_imagery

Of course it would be great to have them, but the cost is pretty exorbitant (sic).


Metamemesis

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Re: Stupid Questions :o
« Reply #352 on: July 13, 2015, 06:08:01 PM »

Of course it would be great to have them, but the cost is pretty exorbitant (sic).

You'd be surprised. https://www.planet.com/

The CEO, Will Marshall, is planning on making much of the data and imagery open-source and freely available.

Nick_Naylor

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Re: Stupid Questions :o
« Reply #353 on: July 13, 2015, 10:23:39 PM »

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?


If you find it, we will discuss. It might be TMI for many/most purposes, but super-hi-res images would undoubtedly be helpful when something is interesting but too small to see in the standard ones.

oren

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Re: Stupid Questions :o
« Reply #354 on: July 13, 2015, 10:57:35 PM »
Stupid questions:

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?

Well of course, lots of interest and I'm sure many practical uses. But how does one obtain such images?

slow wing

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Re: Stupid Questions :o
« Reply #355 on: July 14, 2015, 07:37:48 AM »
Metre-scale resolutions over the Arctic ice would presumably be very valuable to scientists.

One obvious application would be surveying & measuring iceberg size distributions throughout the ice pack.

Tor Bejnar

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Re: Stupid Questions :o
« Reply #356 on: July 14, 2015, 03:45:39 PM »
Icebergs are from glaciers or ice shelves.  Functionally all the ice we see in the Arctic Ocean is in ice floes.  There will be a few icebergs in Nares Strait, Baffin Bay and Greenland Sea (from Greenland glaciers), and probably some in the Canadian Arctic Archipelago (CAA).  I understand virtually all the ice shelves on the north side of Elsmere Island are gone.
Arctic ice is healthy for children and other living things.

Vergent

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Re: Stupid Questions :o
« Reply #357 on: July 14, 2015, 04:45:29 PM »
Stupid questions:

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?

Well of course, lots of interest and I'm sure many practical uses. But how does one obtain such images?

Google Earth's android app is now giving 10 cm resolution images..........Further, they are rendering them into psudo-3D!!?? Here are 2 views of the same A380 at LAX.



3D image splicing issues are apparent, But wow, how do they do it? I can pan around and see all 4 sides of my house. Unfortunately, they do not do ice. Maybe, if we asked very nicely...................

Bob Wallace

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Re: Stupid Questions :o
« Reply #358 on: July 14, 2015, 06:18:18 PM »
Not sure the question is stupid, but I'm putting it here in the event that it's been answered several times before and I've missed it.

Why is the CAA so resistant to melt?  Is it trapped multi-year ice which has no opportunity to open up the water for direct heating by moving around as old ice does in other regions?

Rick Aster

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Re: Stupid Questions :o
« Reply #359 on: July 14, 2015, 06:51:29 PM »
My impression on the northernmost channels in Canada is that it is not just stuck ice, but some of the thickest ice in the Arctic. Thick ice was a permanent feature in a broad area northwest of Greenland and the Canadian Arctic Archipelago until a few years ago, and it seems like there is still some of this thick ice hanging around. Two factors that partially explain the thicker ice: the coastline makes it easy for ice to form in the early fall by giving ice a place to stick, and ice pushed against the coast can pile up to form thicker ice.

ghoti

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Re: Stupid Questions :o
« Reply #360 on: July 14, 2015, 07:22:49 PM »
I think that the northern most channels have a lot of ice imported. The WWF has a program called The Last Ice based in that area. Their idea is the last ice will be there when more southern ice disappears because of the import from the central basin.

Bob Wallace

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Re: Stupid Questions :o
« Reply #361 on: July 15, 2015, 04:04:12 AM »
I think that the northern most channels have a lot of ice imported. The WWF has a program called The Last Ice based in that area. Their idea is the last ice will be there when more southern ice disappears because of the import from the central basin.

So the ice in those channels is Arctic foie gras?  I can see that. 

Daniel B.

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Re: Stupid Questions :o
« Reply #362 on: July 15, 2015, 04:25:14 PM »

oren

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Re: Stupid Questions :o
« Reply #363 on: July 15, 2015, 06:06:53 PM »
The Royal Astronomical society is hardly tabloid material.

http://www.ras.org.uk/news-and-press/2680-irregular-heartbeat-of-the-sun-driven-by-double-dynamo

As I understand it, unscientifically speaking, the main criticism is not that the Maunder minimum can't happen as predicted, but that its effect on global temperatures will not cause a mini ice age or anything of the sort, instead causing only a small bump in the temp charts.

jdallen

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Re: Stupid Questions :o
« Reply #364 on: July 15, 2015, 06:14:30 PM »
The Royal Astronomical society is hardly tabloid material.

http://www.ras.org.uk/news-and-press/2680-irregular-heartbeat-of-the-sun-driven-by-double-dynamo
No, but it's utility depends on how you intend to use the references it provides. Zarkhova's paper has been disingenuously and ignorantly misinterpreted by a small herd of tabloids and AGW "denialist" sites. It gets worse, as they also misinterprete what actually took place during the Maunder Minimum.

The paper she published implies insulation *might* decrease by 1/10th of 1% - which is less than the increase caused by human sourced GHG's. It may not decrease that much nor will it stay down.

So what is your question?

This space for Rent.

DavidR

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Re: Stupid Questions :o
« Reply #365 on: July 16, 2015, 12:48:55 AM »
The Royal Astronomical society is hardly tabloid material.

http://www.ras.org.uk/news-and-press/2680-irregular-heartbeat-of-the-sun-driven-by-double-dynamo
No, but it's utility depends on how you intend to use the references it provides. Zarkhova's paper has been disingenuously and ignorantly misinterpreted by a small herd of tabloids and AGW "denialist" sites. It gets worse, as they also misinterprete what actually took place during the Maunder Minimum.

The paper she published implies insulation *might* decrease by 1/10th of 1% - which is less than the increase caused by human sourced GHG's. It may not decrease that much nor will it stay down.

So what is your question?
If this prediction holds it will  remove one of the main cause of fluctuation in global temperatures for about the next 40 years.  Global temperatures will continue to rise but there will be no long term declines that  we typically see as the sunspot count  returns to a minimum.  Most decades show several years of reduced temperatures after the solar maximum however with no significant maximums there will be no significant declines.  We won't see another so - called 'hiatus' for  decades.
Toto, I've a feeling we're not in Kansas anymore

Rick Aster

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Re: Stupid Questions :o
« Reply #366 on: July 16, 2015, 01:49:53 AM »
The Royal Astronomical society is hardly tabloid material.

http://www.ras.org.uk/news-and-press/2680-irregular-heartbeat-of-the-sun-driven-by-double-dynamo
No, but it's utility depends on how you intend to use the references it provides. Zarkhova's paper has been disingenuously and ignorantly misinterpreted by a small herd of tabloids and AGW "denialist" sites. It gets worse, as they also misinterprete what actually took place during the Maunder Minimum.

The paper she published implies insulation *might* decrease by 1/10th of 1% - which is less than the increase caused by human sourced GHG's. It may not decrease that much nor will it stay down.

So what is your question?

I am afraid many readers (of the news stories) could be confused by the "60% reduction." Some of the news stories try to make you think the sun will be 60% less bright for a decade or two, but of course that would be impossible. To be very clear about that, the difference in brightness would be so slight that it would not be detectable without carefully calibrated equipment. Another problem with the way the stories are written is that they imply the astronomers are predicting some form of an ice age, when in reality the ice age prediction was made by the so-called journalists. A third problem is that the story, despite being a fabrication, was picked up by wire services and repeated all over the place.

seaicesailor

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Re: Stupid Questions :o
« Reply #367 on: August 01, 2015, 05:43:54 PM »

Is there a reason why there aren't buoys installed at the Eurasian side of the Arctic?

Thanks.

AySz88

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Re: Stupid Questions :o
« Reply #368 on: August 01, 2015, 08:43:25 PM »
Google Earth's android app is now giving 10 cm resolution images..........Further, they are rendering them into psudo-3D!!?? Here are 2 views of the same A380 at LAX.

(snip)

3D image splicing issues are apparent, But wow, how do they do it? I can pan around and see all 4 sides of my house. Unfortunately, they do not do ice. Maybe, if we asked very nicely...................

Although the view is called "satellite", I'm pretty sure these photos and data are taken by plane.  Maybe we can hire Santa....

anotheramethyst

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Re: Stupid Questions :o
« Reply #369 on: August 03, 2015, 07:12:35 AM »
you mean google street view?  those are actually taken from cars driving down the street. 

AySz88

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Re: Stupid Questions :o
« Reply #370 on: August 03, 2015, 07:20:35 AM »
you mean google street view?  those are actually taken from cars driving down the street.

The example was a rendering of a plane at an airport, so I'm assuming that wasn't something accessible to cars? Unless the 3d derivation technology is a lot better than I thought.

anotheramethyst

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Re: Stupid Questions :o
« Reply #371 on: August 03, 2015, 07:27:43 AM »
oh sorry, you're probably right!!

seaicesailor

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Re: Stupid Questions :o
« Reply #372 on: August 03, 2015, 09:12:05 AM »

Is there good reasons why there aren't buoys installed at the Eurasian side of the Arctic?

I only think of the drift/melt removing them in one/two years, but that doesnt stop people putting them at the NP.

Thanks.

[/quote]

seaicesailor

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Re: Stupid Questions :o
« Reply #373 on: August 04, 2015, 02:01:09 PM »

Is there good reasons why there aren't buoys installed at the Eurasian side of the Arctic?

I only think of the drift/melt removing them in one/two years, but that doesn't stop people from putting them at the NP.

Sorry that I insist, final time I do.
Nobody knows? Is it a Russian secret thing?
 :-\

Thank you !!!  :)

oren

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Re: Stupid Questions :o
« Reply #374 on: August 04, 2015, 05:04:16 PM »

Is there good reasons why there aren't buoys installed at the Eurasian side of the Arctic?

I only think of the drift/melt removing them in one/two years, but that doesn't stop people from putting them at the NP.

Sorry that I insist, final time I do.
Nobody knows? Is it a Russian secret thing?
 :-\

Thank you !!!  :)

I took the liberty of reposting your question in the Buoys thread, someone there might come with the answer.

seaicesailor

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Re: Stupid Questions :o
« Reply #375 on: August 04, 2015, 06:05:59 PM »

Is there good reasons why there aren't buoys installed at the Eurasian side of the Arctic?

I only think of the drift/melt removing them in one/two years, but that doesn't stop people from putting them at the NP.

Sorry that I insist, final time I do.
Nobody knows? Is it a Russian secret thing?
 :-\

Thank you !!!  :)

I took the liberty of reposting your question in the Buoys thread, someone there might come with the answer.

Wow thank you man!
« Last Edit: August 04, 2015, 06:11:33 PM by seaicesailor »

solartim27

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Re: Stupid Questions :o
« Reply #376 on: August 05, 2015, 09:55:06 PM »
I would have thought this discoloration off SoCal was from smoke, but I then noticed it is seasonal, starting in early March.  Could this be sun glare on the satellite equipment or just the reflectance from the surface?  I don't think it's atmospheric, but I suppose it could be.
(There is a nice bit of smoke from the CA Rocky fire up in the corner)
FNORD

Andreas T

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Re: Stupid Questions :o
« Reply #377 on: August 05, 2015, 10:29:44 PM »
If you zoom out to see the whole earth in the geographic view you see that this glare is seen when the satellite is over water at that latitude. Over the year the latitude with that glare moves from south to north of the equator and back again. It therefore is dependent on the position of the sun. If you overlay the orbital track you see that the glare is slightly to the east of the track. This is because the local time of the terra track is a little before midday. The sun which is behind the camera and to the right reflects off the water surface. The position of that glare is to the west in the aqua images which are taken after midday and change position relative to the ground on different days.

helorime

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Re: Stupid Questions :o
« Reply #378 on: August 14, 2015, 04:55:59 PM »
Why is the DMi arctic sea ice extent so much higher than everyone else's?

http://ocean.dmi.dk/arctic/icecover.uk.php
Any sufficiently advanced technology is indistinguishable from magic.

seaicesailor

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Re: Stupid Questions :o
« Reply #379 on: August 14, 2015, 08:52:00 PM »
Why is the DMi arctic sea ice extent so much higher than everyone else's?

http://ocean.dmi.dk/arctic/icecover.uk.php

The total area of sea ice is the sum of First Year Ice (FYI), Multi Year Ice (MYI) and the area of ambiguous ice types, from the OSISAF ice type product.

From the webpage. It includes ambiguous ice. That explains a lot, and nothing at all

Wipneus

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Re: Stupid Questions :o
« Reply #380 on: August 15, 2015, 09:00:40 AM »
Why is the DMi arctic sea ice extent so much higher than everyone else's?

http://ocean.dmi.dk/arctic/icecover.uk.php

I find the graph raises a lot of questions:

Quote
The ice extent values are calculated from the ice type data from the Ocean and Sea Ice, Satellite Application Facility (OSISAF), where areas with ice concentration higher than 15% are classified as ice.

So, instead of directly using sea ice concentration, ice classification is used and they rely on a undocumented (AFAIK) feature that concentrations below 15% will be tagged as open water.

The reason why they do not use the sea ice concentration product from OSISAF is that a wide (~50km) coastal band is masked out. Due to the land spill over effect, this area would record lots of "false" ice. Calculation extent from SIC would lead to far lower values than (NSIDC, JAXA, Uni Hamburg).

There are newer experimental products that do attempt to calculate the concentration in this area. I am looking in to these an am not impressed: there is still a lot of false ice visible which may well explain why even these newer experimental products give greater total extent than other products.

SCYetti

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Re: Stupid Questions :o
« Reply #381 on: February 14, 2016, 07:07:50 PM »
I have a stupid question about the heat content of water at the freezing point. I haven't attended college so I'm going to word my question at a high school level, using grams and calories.

Water freezes at 0C. It takes about 1 calorie to raise or lower the temperature of 1 gram 1 degree C. 80 calories must be lost from a gram at 0C to change it from liquid to ice. Though the freezing point of sea water is lower I assume this is true of the Arctic Ocean as well. So my question is can we discern the actual energy content of freezing temperature water? Shouldn't we expect a pause in temperature increase as the water changes from almost freezing to almost warming?

In other words couldn't there be a large change in enthalpy without a change in temperature?

oren

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Re: Stupid Questions :o
« Reply #382 on: February 14, 2016, 10:30:33 PM »
I have a stupid question about the heat content of water at the freezing point. I haven't attended college so I'm going to word my question at a high school level, using grams and calories.

Water freezes at 0C. It takes about 1 calorie to raise or lower the temperature of 1 gram 1 degree C. 80 calories must be lost from a gram at 0C to change it from liquid to ice. Though the freezing point of sea water is lower I assume this is true of the Arctic Ocean as well. So my question is can we discern the actual energy content of freezing temperature water? Shouldn't we expect a pause in temperature increase as the water changes from almost freezing to almost warming?

In other words couldn't there be a large change in enthalpy without a change in temperature?

I can answer in two directions, let me know if it helps any (and beware as I might be wrong):
First, as you heat up 1 gram of ice with a constant supply of 1 calorie per second, you will get a temperature rise of 1 deg/sec until you hit 0deg, then for 80 sec you will get no temp rise, and then you will return to the temp rise rate of 1 deg/sec (but it won't be ice anymore of course).
Second,  if you add 40 calories to 1gr of 0deg ice, the way I understand it is you get 0.5gr ice and 0.5gr water. The energy goes into the phase change itself.

Andreas T

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Re: Stupid Questions :o
« Reply #383 on: February 14, 2016, 11:15:42 PM »
you can actually see that effect if you look at the DMI north of 80deg surface temperature graph. There is a steep temperature rise when the sun appears in spring but the those temps are stuck close to 0 deg C with 24h sunshine. Its a big ice and water mixture which won't increase its temperature until all the ice is melted, despite loads of heat energy going into it.

SCYetti

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Re: Stupid Questions :o
« Reply #384 on: February 15, 2016, 02:33:37 PM »
Oren and AndreasT thank you for your responses to my stupid question. But it is the nature of things that the difference between stupid and genius is that genius has limits. Thus I have tons more questions.

I recently set my refrigerator  to too low a setting and everything froze except the bottles of soft drinks. But when I opened a bottle it immediately filled with ice. It seemed to be more ice than could be accounted for by merely the temperature change of the expanding gas. It seems pressure can constrain freezing as it does boiling. The pressure at the depth of 10 meters, I would assume, are greater than the pressure in my drink bottle. Could the water absorb or release a great amount of latent energy without temperature change or phase change?

SteveMDFP

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Re: Stupid Questions :o
« Reply #385 on: February 15, 2016, 03:41:03 PM »
Oren and AndreasT thank you for your responses to my stupid question. But it is the nature of things that the difference between stupid and genius is that genius has limits. Thus I have tons more questions.

I recently set my refrigerator  to too low a setting and everything froze except the bottles of soft drinks. But when I opened a bottle it immediately filled with ice. It seemed to be more ice than could be accounted for by merely the temperature change of the expanding gas. It seems pressure can constrain freezing as it does boiling. The pressure at the depth of 10 meters, I would assume, are greater than the pressure in my drink bottle. Could the water absorb or release a great amount of latent energy without temperature change or phase change?

I'll chime in from a background of moderate general science literacy.  I think the soda bottle experience is only distantly related.  I suspect the answer to your final guestion (at least for a "great amount" of latent energy is "no."

What's going on with the soda bottle is not that the pressure on water molecules is preventing ice formation (much), but that the pressure on CO2 molecules is tending to force them to stay in solution, rather than bubbling out.  The physical process of ice crystal formation requires that other molecules (salt ions, sugar molecules, CO2, whatever) be forced out of the expanding crystals.  The higher the molar amount of foreign dissolved molecules, the colder the temp has to be to allow crystals to form.

Your very cold but liquid soda bottles would freeze instantly when pressure is released only because CO2 can then immediately bubble out of solution.  Instantly removed from the water, the temp at which ice can form is substantially above current temp.  If I'm correct in this thinking. a temperature reading of the new ice would be at or below 0 degrees C, but higher than the ambient temp in the refrigerator. 

A corollary to all this is that any gas is much more soluble at great ocean depth than at the surface.  This has some relevance  for climate issues with methane, which dissolves into water if released at great ocean depth, but bubbles to the surface when released from shallower waters.


Peter Ellis

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Re: Stupid Questions :o
« Reply #386 on: February 15, 2016, 06:04:44 PM »
http://www.thenakedscientists.com/HTML/experiments/exp/freezing-lemonade-bottles/

Yes, the main effect here is that carbonated water has a freezing point lower than zero degrees.  If the bottle is then chilled to a point where ordinary water freezes, but carbonated water does not, then allowing the CO2 to escape will trigger freezing.

SCYetti

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Re: Stupid Questions :o
« Reply #387 on: February 15, 2016, 06:48:34 PM »
Please check this out

Peter Ellis

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Re: Stupid Questions :o
« Reply #388 on: February 15, 2016, 10:54:38 PM »
I considered supercooling, but couldn't see any reasonable way that could affect the carbonated drinks and not the other bottles in the same fridge.

opensheart

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Re: Stupid Questions :o
« Reply #389 on: February 18, 2016, 03:20:31 AM »
I would ask a clarifying question about freezing sea water.

Most places say sea/salt water freezes at about -1.8C or -1-.9C or -2C, depending on the salinity.   

There are a couple references in this forum about air temps being -11C. 

At first I was thinking that meant you needed both,  water at least -1.8C and an air temp of -11 or below.   But I was trying to track this down and verify this.   I'm not finding this -11C mentioned other places.   Here on this blog it seems to trace back to 'wayne'.   And searching through his EH2R blog I found this quote:

Quote
sea water was so warmed air temperatures needed to be below -11 C.

Which leads me to guess this -11C number may be what is required to freeze the sea when the water temp is wamer than -1.8C.   

Can someone clarify this?

Is there some ratio here, like: salt water at temp X will need air temp of Y to freeze?

Pmt111500

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Re: Stupid Questions :o
« Reply #390 on: February 18, 2016, 03:37:48 AM »
I would ask a clarifying question about freezing sea water.

Most places say sea/salt water freezes at about -1.8C or -1-.9C or -2C, depending on the salinity.   
O
There are a couple references in this forum about air temps being -11C.   Here on this blog it seems to trace back to 'wayne'.   And searching through his EH2R blog I found this quote:

Quote
sea water was so warmed air temperatures needed to be below -11 C.

Which leads me to guess this -11C number may be what is required to freeze the sea when the water temp is wamer than -1.8C.   

Can someone clarify this?

Is there some ratio here, like: salt water at temp X will need air temp of Y to freeze?

I'm not too sure of this, likely this is an observational measure and not derived from purely theoretical grounds. I'd imagine perfectly still sea water would indeed freeze at the -2 it's supposed to. In reality there are waves and tides mixing the uppermost layer so the surface tends to constantly be in just above the still water freezing point. -11 would then be about the air temperature needed to drain the deeper supply of heat so the surfacing waterr freezes instanly, or possibly during one night. Further clarification is probably needed for this, but this is how I see it. This would be the ocean equivalent of the effect seen in streams and rivers in which the faster running sections freeze the latest.
« Last Edit: February 18, 2016, 04:05:33 AM by Pmt111500 »
Cooling the outside by heat pump.

ecojosh

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Re: Stupid Questions :o
« Reply #391 on: February 18, 2016, 05:13:01 AM »
My experience in British Columbia is that -10 or -11c is indeed about when the sea starts to freeze over.

Andreas T

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Re: Stupid Questions :o
« Reply #392 on: February 18, 2016, 09:16:11 PM »
Something that is different between ice forming on freshwater and ice on seawater is that  saltwater is at its densest when it is at the freezing temperature, so it will sink relative to water which is even very little warmer by density driven convection. The water column (the part of it which has the same salinity as the top layer) has to reach freezing temperature before it freezes.
But the ice itself, through "freezing out" salt, is less dense than seawater. When air is much colder than the water the surface layer can cool fast enough and form ice before it is accelerated downwards (with temperature and density gradients being not too large)
https://nsidc.org/cryosphere/seaice/index.html
Once there is a layer of ice, which is cooled by cold air (and radiative cooling) a thin boundary layer at its bottom can have a temperature gradient (lowest at the ice surface) which adds further freezing to the ice bottom.
Freshwater on the other hand has its maximum density at 4 deg C so less water has to be cooled below that temperature to start freezing the top layer.

johnm33

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Re: Stupid Questions :o
« Reply #393 on: February 19, 2016, 01:13:50 PM »
As best as I recall it wayne  commented about ice formation on the blog about three years ago, essentially saying the same as Andreas T s comment above.
My own question, IIRC sea ice travels at about 2-3% of windspeed, but given present conditions I want to know how it accelerates in persistent winds, and how winds at various speeds affect it's movement. For instance there must be some point where faster winds become detatched from the surface due to turbulence.

jai mitchell

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Re: Stupid Questions :o
« Reply #394 on: February 22, 2016, 07:30:58 AM »
My stupid question of the day:  When calculating the negative forcing associated with aerosols, are the Lapse Rate and Water Vapor feedbacks included in the total forcing effect?
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Richard Rathbone

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Re: Stupid Questions :o
« Reply #395 on: February 23, 2016, 11:54:55 AM »
My stupid question of the day:  When calculating the negative forcing associated with aerosols, are the Lapse Rate and Water Vapor feedbacks included in the total forcing effect?

Depends on the source you are looking at. If its old it won't have, if its recent it might have but you'll need to check the paper to be sure.

jai mitchell

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Re: Stupid Questions :o
« Reply #396 on: February 25, 2016, 07:11:30 PM »
was able to find the answer, forcing does not include feedbacks it has different units.  ECS includes feedbacks to determine a time-rated forcing value in future projections. 

forcing is a measure of energy per square meter and is instantaneous at any given time.
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johnm33

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Re: Stupid Questions :o
« Reply #397 on: April 01, 2016, 10:12:15 PM »
I've been trying to find something definitive about tides in Kangia/jakobshavn fjord, anyhow I decided to have a shot at ball park figures. What I want is some estimate of max and minimum turnover of water possible per tide. So tidal min. with onshore winds when there's a logjam of icebergs stopping any movement at the cill, verses tidal max with full bore offshore winds and bergs racing down the fjord. In Km3 I get from .1 to maybe 10! [7.8]  Why am I wrong?

johnm33

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Re: Stupid Questions :o
« Reply #398 on: April 04, 2016, 10:51:11 PM »
These are my assumptions
. First for the minimum, the fjord is full of icebergs both it and the side channels are frozen over and covered in snow. There's a logjam of icebergs sitting on the cill there's no surface movement, and there's a low tide in Disko

say .4m .
So 55x6x.0004[km]=0.132Km3 the tide simply doesn't have the power to push past the 'dam' into the fjord.
Now the max. The whole fjord and the side channels are fluid the run of increasing tides have destroyed the logjam, there are powerful winds blowing offshore adding to the inertia of the icebergs as they flow out in the surface freshwater current. Out in Baffin strong winds have been blowing the 1m thick ice south for days, and the tidal range is at it's peak.

The surface outflow of the ebbing tide say 55x6x.0024[km]=.792 , plus the side channels say x2.2 so 1.74 and to that add in some inertia for the ongoing fresh water surface current continuing to run throughout the incoming tide, [which comes in at the base] say 70% so maybe 2.96Km3 the last forcing factor is when conditions are right [and it looks like they are at present] there's an increased flow of warm irminger water thats drawn up from the south from the wgsc[slope current] and when it's forced to run it preferentially flows up the deep channels connected to deeper Baffin waters, only those fjords with such a connection [IIf does] experience this forcing and since it's difficult to find any information on it [the flow] some serious speculation. Would an undersea river forcing it's way east double the force of the tidal flow? My own view is that it might peak at something like 3 times the flow and once established it's inertia would carry it through into the ebb whilst the necessary conditions for it's forcing prevail. So best guess at peak tidal flux 7.8Km3 and since it's speculation +/- 25% margin of error.
Why am I wrong?

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Re: Stupid Questions :o
« Reply #399 on: April 11, 2016, 06:48:52 PM »
This may be a doozy of a Stupid Question, but it puzzles me:

Why not substitute Propane for natural gas?  (As an interim measure, while we ramp up renewables.)

I believe propane generates slightly less power than natural gas, but surely the reduction in greenhouse gas effect would make that worthwhile. 
People who say it cannot be done should not interrupt those who are doing it.