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Author Topic: a new normal for the Arctic  (Read 5564 times)

Pmt111500

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a new normal for the Arctic
« on: October 03, 2013, 05:47:48 AM »
by Jeffries, Overland and Perovich (Physics Today) , a pretty wide-ranging summary article of everything arctic

http://www.physicstoday.org/resource/1/phtoad/v66/i10/p35_s1?bypassSSO=1

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Re: a new normal for the Arctic
« Reply #1 on: October 03, 2013, 06:50:41 PM »
by Jeffries, Overland and Perovich (Physics Today) , a pretty wide-ranging summary article of everything arctic

http://www.physicstoday.org/resource/1/phtoad/v66/i10/p35_s1?bypassSSO=1

Great article.

ggelsrinc

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Re: a new normal for the Arctic
« Reply #2 on: October 05, 2013, 01:54:19 AM »
by Jeffries, Overland and Perovich (Physics Today) , a pretty wide-ranging summary article of everything arctic

http://www.physicstoday.org/resource/1/phtoad/v66/i10/p35_s1?bypassSSO=1

Overall, it's a great article. I particularly like the way they used history and kept things simple enough to introduce their subjects to people without just scientific backgrounds. Communication on that level makes things convincing to the average person and it's important.

Since there is little sense in discussing things I agree with, I did find two things in the article I felt were lacking. To be fair to them and make it easy for someone to find, I'll quote the entire paragraph and section it was in. I'll add bold to identify specifics.

In the

Quote
Socioeconomic consequences

section and first paragraph, I found:

Quote
The Arctic Ocean and adjacent subarctic seas supply food for indigenous peoples whose culture and traditional way of life are affected by the prevalence of open water. They now must travel farther offshore—over more unstable ice or through increasingly rough seas—to hunt mammals that live in icy habitats. The wave action on thawing and vulnerable shorelines accelerates the coastal erosion and is affecting village, archaeological, and sacred sites. In Alaska, the estimated cost of relocating a single village farther inland is on the order of $100 million.

Source: http://www.physicstoday.org/resource/1/phtoad/v66/i10/p35_s1?bypassSSO=1

There definitely has been Inuit villages affected by global warming, but the last example I investigated, which had a $100 million price tag wasn't a coastal village and the village wasn't built long ago. I recall articles claiming the problems were related to global warming and that's why I took the time to examine it. My conclusion was the village was located next to a meandering river and was located there to make it easy to transport materials to build it. I couldn't find a global warming connection like many press articles stated and viewed the press articles as misleading. I think the problem was stupidity, trying to do things on the cheap, and since our government was involved, it should be accountable and assist in relocation. I'm a sixteenth Native American, have examined the 100 poorest counties in America (and there will always be 100 poorest counties). Areas with large Native American populations rank near the top. If the data supported global warming, I would use it, but I call a spade a spade.

In all fairness, I recall the news articles of that time and consider using that example as an oversight. They should have picked a better example to make their point, but it's a minor thing. I'm just giving my honest assessment and not claiming it has to be fact. 

The major thing I saw in the article was in the second paragraph of the section entitled:

Quote
Sources of Arctic amplification

Quote
The spatial synthesis of atmospheric data, known as reanalysis fields, offers evidence that the poleward transport of energy in the troposphere leads to higher Arctic air temperatures at the surface, particularly in winter. Satellite measurements indicate that the heat flux into the Arctic is accompanied by an increase in cloud cover and water vapor. Clouds amplify the effects of surface warming by augmenting the net downward long-wave radiation flux and the greenhouse effect of water vapor (see the article by Bjorn Stevens and Sandrine Bony in Physics Today, June 2013, page 29), particularly in winter and spring. Model studies indicate that the warming might be further enhanced by the rise in atmospheric concentrations of carbon aerosols, known as black carbon or soot, which also absorb solar radiation. Black carbon deposition might be reducing the albedo and thus accelerating the melting of sea ice and of snow and ice on land.

Source: http://www.physicstoday.org/resource/1/phtoad/v66/i10/p35_s1?bypassSSO=1

Disclaimer: Again, let me point out the sentences in bold were not in the original source article.

When I attempted to log onto the link, it was the same site requiring login. My personal choice to not login has no bearing on the quality of the site, which isn't unfamiliar to me. My problem with what was said is it is indeed true that:

Quote
Clouds amplify the effects of surface warming by augmenting the net downward long-wave radiation flux and the greenhouse effect of water vapor

Source: http://www.physicstoday.org/resource/1/phtoad/v66/i10/p35_s1?bypassSSO=1

but that isn't the whole story.

Quote
Clouds increase the global reflection of solar radiation from 15% to 30%, reducing the amount of solar radiation absorbed by the Earth by about 44 W/m². This cooling is offset somewhat by the greenhouse effect of clouds which reduces the outgoing longwave radiation by about 31 W/m². Thus the net cloud forcing of the radiation budget is a loss of about 13 W/m².[1] If the clouds were removed with all else remaining the same, the Earth would gain this last amount in net radiation and begin to warm up. These numbers should not be confused with the usual radiative forcing concept, which is for the change in forcing related to climate change.

Source: http://en.wikipedia.org/wiki/Cloud_forcing

Logic should dictate an increase in clouds is a net negative and it's only logical, it isn't a net negative without sunlight. Logic should also dictate, sunlight is the important factor to melt sea ice. Evaporation requires photons striking water, so it isn't just a temperature thing. In the arctic, more sunlight increases evaporation creating more cloud cover decreasing evaporation by sunlight. 

When the subject of negative forcing was brought up in ASIB, I examined what I could over time. I haven't examined the subject close enough to know for sure that increasing cloud cover is a net negative to the arctic, but I sure hope it is. I grew up with arctic sea ice on my planet and I want others to have the same.
« Last Edit: October 05, 2013, 12:08:41 PM by ggelsrinc »

TerryM

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Re: a new normal for the Arctic
« Reply #3 on: October 05, 2013, 08:58:43 PM »
My understanding is that cloud cover is a negative feedback while the sun is high in the sky and a positive feedback feedback the rest of the time. It is unfortunate that the linked article is paywalled but I do recall some of our posters addressing the issue a few months back.
MJJ may see negative forcing due to reflected insolation but the rest of the year the long wave radiation would be more of a factor as I understand it. The paleo record of cold blooded animals living in the Arctic has been explained by dense clouds retaining summer heat through the long dark winters so it appears that at some point the positive overcomes the negative feedback.
Whether we have reached this stage yet may be up for grabs.
Terry

ggelsrinc

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Re: a new normal for the Arctic
« Reply #4 on: October 06, 2013, 12:07:11 AM »
My understanding is that cloud cover is a negative feedback while the sun is high in the sky and a positive feedback feedback the rest of the time. It is unfortunate that the linked article is paywalled but I do recall some of our posters addressing the issue a few months back.
MJJ may see negative forcing due to reflected insolation but the rest of the year the long wave radiation would be more of a factor as I understand it. The paleo record of cold blooded animals living in the Arctic has been explained by dense clouds retaining summer heat through the long dark winters so it appears that at some point the positive overcomes the negative feedback.
Whether we have reached this stage yet may be up for grabs.
Terry

Thank you for your input, Terry!

I totally agree cloud cover without sunlight will trap heat, but in the arctic, what difference does it make in winter? The temperatures and conditions in winter are still going to allow sea ice to form. I think the dynamics of arctic sea ice are more dependent on what happens during melt, specifically, that enough sea ice remains in that landlocked area.

Perhaps my point is vague and I need to explain it better. I don't think heat matters much in an arctic environment during winter, because I don't think the heat will be around long enough to matter. From my understanding of how fast ASI can remove brine, we could make ASI by intentionally fragmenting it at the right time. That too would release heat from the ocean, but I don't think it matters. It doesn't have to be too cold, just cold enough.

I would like to see a study examining global and arctic cloud formation changes during the satellite era, but I don't think it's ever been done. Obviously, one cloud doesn't equal another, so some type of metrics would have to be established to evaluate changes based on net radiative forcing. Studies evaluating aerosols would also be helpful.

Yesterday I fixed a problem with my computer generated by a change in IP address. Overall, I think it's an excellent article and I should examine my objections in more detail by signing up and login their site. At this point, I was just trying to discuss the issue. The jury isn't deliberating, because the trial isn't over.