Re: Scientists discover why is the North Pole frozen

From: george of the jungle (keys_at_somewhere.not.here)
Date: 02/26/05 

Date: Fri, 25 Feb 2005 18:19:33 -1000

On 25 Feb 2005 16:15:02 -0800, "Daryl Krupa" <icycalmca@yahoo.com>
wrote:

>
>george of the jungle wrote:
>> On 24 Feb 2005 20:10:08 -0800, "Daryl Krupa" <icycalmca@yahoo.com>
>> wrote:
>> >george of the jungle wrote:
><snip>
>> >> Cooling of salty Atlantic water by cold Arctic air
>> >> creates dense water that sinks.
>> >
>> >Tree-hugger:
>>
>> Me? I like open space.
>
>http://tinyurl.com/3szq8
>
>> > Okay fine, but does that explain the Labrador Current, or
>> >the Greenland Current?
>>
>> Explain? No. But it's consistent with those currents.
>>
>> The Coriolis effect bends the Atlantic water towards Norway and the
>> return Arctic flow towards Labrador. Right now the cold water has
>> pushed down to north Florida.
>
> I thought that, because the south-flowing water is
>moving eastward slower than the north-flowing water,
>the Coriolis efect would tend to shift such flows
>clockwise in the Northern Hemisphere;
>I'm not sure what sort of pattern you are describing,
>but you seem to be describing a counter-clockwise loop.
> Please explain futher.

http://www.aquatic.uoguelph.ca/oceans/ArticOceanWeb/Currents/maincur.htm

I'm describing the Labrador current. Water moving from the Arctic to
the Atlantic has lower vorticity - spin- than water from the Atlantic
moving into the Arctic. They are both deflected to the right. Thus
the Coriolis effect interacting with the prevailing winds causes a
warm current on the coast of Norway and a cold current on the Labrador
Coast.

>> > Also, I thought that the hypersaline water is what is left
>> >behind after some near-surface seawater water freezes onto
>> >the underside of the pack ice. Some of the water molecules
>> >are frozen out, and most of the salt remains in the seawater.
>>
>> True, but if it started as Arctic water that's fresh,
>> it mixes with the upper layer of fresh water and doesn't sink.
>
> The Arctic sea ice that I've tasted has all been salty.
> It takes special knowledge to be abble to identify Arctic
>sea ice that is suitable for drinking.

I didn't mean drinking water. I meant water that is relatively fresh
for seawater because it has a substantial component of Russian river
water.

> I'm not sure where the idea that Arctic sea ice is frozen
>fresh water comes from, or the idea that the Arctic Ocean
>surface is so fresh that salt is not segregated and
>concentrated during the freezing process.

It comes from salinity and current measurements.

>> >> There are other problems with the various models of the THC but
>> >> there's not enough time to go further.
>> >
>> > Got a relevant URL handy, or better yet, a hard-copy ref.?
>>
>> Sorry, I have ADD. References and details are my *big* weakness.
><snip>
>
> Then don't tease. <g>
>
>> >It also sought to describe changes in productivity and
>> >seasonality related to a change in upwelling, but it posits a
>> >_reduction_ in productivity and a
>> >_decrease_ in seasonality related to an
>> >_increase_ in upwelling,
>> >off of California, but later (1.7 Myr ago).
>> > Note that Haug, etc. would have it that a
>> >_decrease_ in upwelling would also cause a
>> >_reduction_ in productivity.
>> >
>> That makes sense because the upwelling water is nutrient rich.
>
> Do you mean, then, that the California model, above, does
>_not_ make sense?

Increased upwelling should increase productivity.

> What, exactly, is it above that makes sense to you, please?
>
>> >"1.7 Myr ago, a further increase in wind-driven upwelling
>> >or shoaling of the thermocline, accompanied by decreased
>> >stratification at least seasonally, as occurs today,
>> >would have caused total CaCO3 production to drop and
>> >seasonality to increase."
>>
>> CaCO3 production drops with upwelling because upwelling water is
>> enriched in CO2. However, silica rich sediment production can be
>> increased as in the Miocene.
>
> Hmmm.
>
><snip>
>> > This is where it gets chancy: the higher alberdo of the
>> >sea ice cover reduced solar heat input, cooling northern
>> >climate, but at the same time it insulated the Arctic Ocean
>> >from heat loss to the atmosphere. That insulative effect
>> >supposedly reduced the formation of North Atlantic Deep Water
>> >(NADW) and its associated downwelling, and so the global
>> >conveyor was "short-circuited", and no more NADW made its way
>> >around Africa and Australia to eventually upwell in the North
>> >Pacific.
>>
>> I don't think so.
>>
>> The NADW upwells in the ACC or mixes with ABW before that.
>
> I agree; Haug & Co.'s illustration is skewed.
>
><snip>
>> > It's explained thusly:
>> >"The added fresh water would have facilitated the formation
>> >of sea ice, which would reflect sunlight and heat back into
>> >space.
>> >It would also act as a barrier blocking heat stored
>> >in the ocean from escaping to the atmosphere above the Arctic.
>> >Both these phenomena would further cool the high latitudes.
>> >In addition, Arctic waters flowing back into the North Atlantic
>> >would have become less cold and salty-short-circuiting the
>> >efficiency of the Ocean Conveyor belt as a global heat pump to
>> >North Atlantic regions."
>>
>> The "conveyor belt" is what caused the cooling in the first place.
>> That argument does not make sense as stated. Thermodynamics tells
>you
>> that the global heat pump would not work if it didn't lose heat.
>
> Agreed. Haug & Co.'s model is not well-explicated, and
>on the face of it contradicts observed behaviour, and
>should not, therefore, be taken at face value.
>
>> By the way the THC is cranking this winter and Europe was warm until
>> recently but areas south of Siberia have suffered from brutal cold.
>
> Have you noticed if that situation has affected the
>curvature of number of Rossby Waves to a significant
>amount?
>
I haven't looked at that. I have no idea. I'm a geochemist trained in
geology with a hobby of meteorology. Physical oceanography is not my
thing.

><snip>
>> > This idea of warming-causing-cooling-causing-less-cooling
>> >is supposed to be a resolution of an "apparent" contradiction,
>> >in that the warm Gulf Stream waters are not supposed to cool
>> >down the Northern Hemisphere.
>> > I don't see it as a clear resolution.
>>
>> No, it's kinda dumb. The first 2 steps are ok but feedback would
>> normally cause an oscillation between #1 and #2. They don't explain
>> #3.
>
> Maybe it's all #2, the result of the deleterious effects
>of long-term consumption of too much #1 (as it's called in
>Strine).
> OR, as a good Canadian boy has often exclaimed,
>"Doh!"
>
><snip>
>> > Lastly, Haug, et al. 2005 does not describe a relationship
>> >between a "short-circuiting" of the ocean conveyor and the
>> >beginning of the stratification of the NPac.
><snip>
>> >This work raised atmospheric CO2 as the possible mechanism by
>> >which polar stratification could, in turn, cause global cooling
>> >and thus participate in a positive feedback.
>> >The sediment core data and climate model output reported here
>> >provide a more direct mechanism by which the development of the
>> >subarctic Pacific halocline set the scene for ice-*** growth
>> >in the Northern Hemisphere."
>>
>> There are missing elements in the paragraph above. Spring/summer ice
>> melt could cause a summer halocline but that would not be warm water
>> and it would mix with winter storms. I don't know what they are
>> talking about.
>
> Nor I; I'm trying to assemble printed copies of the articles
>that they referenced, so that I can do a forensic cryptographic
>investigation of their argument. It's written _en clair_,
>that's for sure.
>
><snip>
>> > AFAICS, the Pliocene ocean conveyor system and
>> >the swings-both-ways effect of increased Gulf Stream warming
>> >in the figures at the next two URLs are truly speculative, and
>> >neither support nor follow from the arguments, modelling, and
>> >evidence in Haug, et al. (2005). Too many cooks in that article?
>> >
>> >http://oceanusmag.whoi.edu/v42n2/haug-en2.html
>> >
>> >http://oceanusmag.whoi.edu/v42n2/haug-en4.html
>>
>> Those diagrams miss the subtleties of the actual currents. The warm
>> return flow runs close to S. Africa and the Gulf stream runs close to
>> N America up to the Outer Banks of NC.
>
> Yep. Again, I'll note that the diagrams do not seem to be
>illustrating the modern situation, but rather an imaginary
>former situation that was supposedly the norm before the
>Pleistocene.

Yes, but it doesn't make sense because the factors controlling the
current positions have not changed significantly. The biggest factor
is the position of the continents. Geologically the Pliocene wasn't
that long ago.

><snip>
>
>> >-----------------------------------------------------
>> >[slightly modified to remove ref's to Figures, etc.]
>> >
>> >news and views
>> >
>> >Nature 433, 809 - 810 (24 February 2005);
>> >doi:10.1038/433809a
>> >
>> >Climate change: Snow maker for the ice ages
>> >
>> >KATHARINA BILLUPS
><snip>
>> >This then provides the configuration on which to build
>> >an ice age: late winter cooling reflects climate cooling,
>> >allowing snow to accumulate; late summer warming
>> >increases the atmosphere's potential to hold moisture and
>> >to load the snow gun.
>>
>> The atmosphere does not "hold moisture". The vapor pressure of water
>> is a function of temperature. It is a fundamental property of H2O.
>
> I think that she was referring to dew point, and not to
>vapour pressure.
>
In any region of the ocean, dew point is a function of water
temperature and atmospheric mixing. Obviously weather (and island
topography) affects it but if you know the water temp over the ocean
you can make a pretty good guess at the dewpoint.

Here is a link to our latest sounding.

http://weather.hawaii.edu/current/soundings/lih/images/lih.skewt.2005022600.png

Today there are very strong winds aloft and the dewpoint is depressed
more than usual from the SST because of strong mixing.

_g

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