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Author Topic: When will the Arctic Ocean (CAB) go Ice Free in Winter?  (Read 23117 times)

Shared Humanity

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #100 on: August 11, 2018, 02:24:24 PM »
Reality is that the guesstimates are all over the place,...

Casually dismissing decades of multidisciplinary science in a single, simple clause because...

...you know better.
« Last Edit: August 11, 2018, 08:27:49 PM by Shared Humanity »

magnamentis

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #101 on: August 11, 2018, 11:49:28 PM »
BBR, saw your maps of temperatures in Iberia and NW Africa for June and July. Well, the temperatures there vary quite a lot from month to month as can be seen here.

Haven't you heard about the difference between climate and weather?
Of all things said on this funny thread, I support the evidence (as measured by the cells of my skin, my June-July electricity bill, and family of mine probing different areas of the Iberian peninsula by the same methods) that this summer in Spain has been mild, even pleasant, with the exception of the first week of August. It is OK now!

The rest is speculation.

Carry on

confirms what i posted earlier. i use the same measurement tools, that with the E-Bill for aircon is a good one but so true and undeniable ;)

i only react to such claims of extreme heat or cold or humidity when i've spent most of the time in the region and in early spring we all commonly agreed that it's a bit extra cools in the mornings. i know which jacket i have to wear on the bike and whether i need the heated handle bars or not ;)

Peter Ellis

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #102 on: August 12, 2018, 10:28:17 PM »
However, as A-Team remarked earlier this melt season, the time of peak solar activity does not overlap well with the time of minimum ice. 

Why would you expect it to?  Even in a world where sunlight is the main cause of ice melt, then the peak solar activity would not coincide with the point of minimum ice but with the peak point of ice loss - i.e. the steepest part of the yearly ice loss curve during the melt season.

As it happens, there's a little bit of extra lag beyond that, because it takes a while for various short-term summer feedbacks (snow melt lowering albedo, melt ponds and leads likewise, and the sheer time taken to melt through the ice layer) to kick in. Not much of a lag though - the point of fastest melt rate typically occurs within 2-4 weeks after the solstice.

The inflection point between melting and freezing (i.e. the annual minimum) happens at or around the equinox, more or less exactly as you'd expect from that being the point where solar input (or rather radiation balance) starts to turn negative.

If you approximate ice extent as a yearly sine wave, it's offset by 1/4 of a cycle from the solar input cycle, exactly as you'd expect if insolation was the main factor affecting melt and freeze-up.  Sure, there are other interesting dynamics from warm air and warm water intrusion - and we discuss them to death every year - but they're second order effects.

Rod

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #103 on: August 13, 2018, 01:27:09 AM »
However, as A-Team remarked earlier this melt season, the time of peak solar activity does not overlap well with the time of minimum ice. 

Why would you expect it to?  Even in a world where sunlight is the main cause of ice melt, then the peak solar activity would not coincide with the point of minimum ice but with the peak point of ice loss - i.e. the steepest part of the yearly ice loss curve during the melt season.

As it happens, there's a little bit of extra lag beyond that, because it takes a while for various short-term summer feedbacks (snow melt lowering albedo, melt ponds and leads likewise, and the sheer time taken to melt through the ice layer) to kick in. Not much of a lag though - the point of fastest melt rate typically occurs within 2-4 weeks after the solstice.

The inflection point between melting and freezing (i.e. the annual minimum) happens at or around the equinox, more or less exactly as you'd expect from that being the point where solar input (or rather radiation balance) starts to turn negative.

If you approximate ice extent as a yearly sine wave, it's offset by 1/4 of a cycle from the solar input cycle, exactly as you'd expect if insolation was the main factor affecting melt and freeze-up.  Sure, there are other interesting dynamics from warm air and warm water intrusion - and we discuss them to death every year - but they're second order effects.

Hmmmm.  Seems like you are attacking me for something I never said.  I never said that I expected peak solar activity to coincide with minimum ice.  I was simply pointing out the obvious in connection with the topic of this thread. 

You can calculate all the sine waves you want, but ignoring the effects of warm water air and warm water intrusion is just silly.   When the ice finally goes, the warm ocean currents are what will kill it. 

John Batteen

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #104 on: August 13, 2018, 03:21:38 AM »
I'm with Rod.  I miss the atmosphere here about 3-5 years ago.  Even 2 years ago.  It used to be straight information.  I loved lurking here and learning.  Now there's a high signal-to-noise ratio requiring much sorting and sifting to get to the goods.  I still enjoy lurking here but...  it's more taxing than it once was.

On topic, about 9 years ago when I was just beginning my journey into self-education on weather and climate, Gavin Schmidt came to the university in the city near me to give some kind of talk.  I drove an hour to get there, and during the Q&A at the end I asked him this very question.  At the time I was disappointed by his answer: "Long after we're dead."  Think about the Great Lakes.  Living in Minnesota at the time, I'm only really familiar with Lake Superior, but it freezes at least a little bit every winter and the adjacent land masses see temperatures into the 80s every year and occasionally 90s.  I know there is a difference freshwater versus salt, but even so.  It will be a long time before the Arctic is that warm.  That much polar night surrounded by large continents for cold air masses.  It will get pretty warm in the summer yet and still freeze in the winter.

bbr2314

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #105 on: August 13, 2018, 03:27:00 AM »
I'm with Rod.  I miss the atmosphere here about 3-5 years ago.  Even 2 years ago.  It used to be straight information.  I loved lurking here and learning.  Now there's a high signal-to-noise ratio requiring much sorting and sifting to get to the goods.  I still enjoy lurking here but...  it's more taxing than it once was.

On topic, about 9 years ago when I was just beginning my journey into self-education on weather and climate, Gavin Schmidt came to the university in the city near me to give some kind of talk.  I drove an hour to get there, and during the Q&A at the end I asked him this very question.  At the time I was disappointed by his answer: "Long after we're dead."  Think about the Great Lakes.  Living in Minnesota at the time, I'm only really familiar with Lake Superior, but it freezes at least a little bit every winter and the adjacent land masses see temperatures into the 80s every year and occasionally 90s.  I know there is a difference freshwater versus salt, but even so.  It will be a long time before the Arctic is that warm.  That much polar night surrounded by large continents for cold air masses.  It will get pretty warm in the summer yet and still freeze in the winter.
The Great Lakes aren't directly adjacent to the Atlantic Ocean for thousands of miles...

Rod

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #106 on: August 13, 2018, 04:40:20 AM »


On topic, about 9 years ago when I was just beginning my journey into self-education on weather and climate, Gavin Schmidt came to the university in the city near me to give some kind of talk.  I drove an hour to get there, and during the Q&A at the end I asked him this very question.  At the time I was disappointed by his answer: "Long after we're dead."  Think about the Great Lakes.  Living in Minnesota at the time, I'm only really familiar with Lake Superior, but it freezes at least a little bit every winter and the adjacent land masses see temperatures into the 80s every year and occasionally 90s.  I know there is a difference freshwater versus salt, but even so.  It will be a long time before the Arctic is that warm.  That much polar night surrounded by large continents for cold air masses.  It will get pretty warm in the summer yet and still freeze in the winter.
The Great Lakes aren't directly adjacent to the Atlantic Ocean for thousands of miles...

I understand his point, and I think you do too bbr.  It is just like the Hudson that we were all talking about a few days ago. While your statement is true, it was unnecessary.  Don't be hypocritical.  It hurts your credibility.  I enjoy your posts and don't want to see you moderated or banned like Hyperion was. 

HapHazard

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #107 on: August 13, 2018, 04:53:05 AM »
I'm with Rod.  I miss the atmosphere here about 3-5 years ago.  Even 2 years ago.  It used to be straight information.  I loved lurking here and learning.  Now there's a high signal-to-noise ratio requiring much sorting and sifting to get to the goods.  I still enjoy lurking here but...  it's more taxing than it once was.

Sad part is that it will only get worse as time goes on - in conjunction with the Arctic sea ice itself.  :(
If I call you out but go no further, the reason is Brandolini's law.

jdallen

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #108 on: August 13, 2018, 06:49:51 AM »

Just a back-of-the-envelope calculation:
  • The energy required to melt enough ice for a 30m sea-level-rise (about 1016 cubic meters of water)
    1.08 * 1019 kg * 3.335 * 105 J/kg
    = 1021 Wh
  • The energy absorbed by the whole earth surface for a radiative forcing of 1 Watt/m² over 7 years is
    5.1 * 1014 m² * 1 W/m² * 7 * 8760 h 
    = 3.13 * 10^19 Wh


Thank you. I was about yo go through exactly the same exercise.
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John Batteen

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #109 on: August 13, 2018, 07:44:08 AM »
I think seasonal ice will cling to the edges of the continents for some time to come.  I could see some portion of the interior or Atlantic-facing areas staying ice free over winter if kept well mixed in the not so distant future.

Dharma Rupa

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Re: When will the Arctic Ocean (CAB) go Ice Free in Winter?
« Reply #110 on: August 13, 2018, 01:58:51 PM »
I think seasonal ice will cling to the edges of the continents for some time to come.  I could see some portion of the interior or Atlantic-facing areas staying ice free over winter if kept well mixed in the not so distant future.

Which was my original question.  I asked only about the CAB -- areas that were not close to the continents or tightly surrounded by land.

It is my guess that when the CAB goes ice-free in Summer it also goes ice-free in Winter.