Re: Scientists discover why is the North Pole frozen

From: george of the jungle (keys_at_somewhere.not.here)
Date: 02/25/05 

Date: Thu, 24 Feb 2005 22:16:19 -1000

On 24 Feb 2005 20:10:08 -0800, "Daryl Krupa" <icycalmca@yahoo.com>
wrote:

>
>
>george of the jungle wrote:
>> On 24 Feb 2005 09:34:16 -0800, "Daryl Krupa" <icycalmca@yahoo.com>
>> wrote:
>
>> ><snip>
>> >
>> > Heh? I always thought that the principal driver in
>> >that system was the formation of North Atlantic
>> >Deep Water, that is obliquely referred to above, but
>> >its formation is there ascribed to evaporative cooling,
>> >rather than the usual explanation of sinking of hyper-
>> >saline cold water after the surface layer freezes.
>> > But Haug, etc. want to blame it all on wind, and
>> >differential salinity in the Pacific and Atlantic.
>> >
>>
>> There is a French web site - Mercator Ocean that has high
>> resolution maps of the North Atlantic. The formation of
>> deep water looks more complicated than most models would
>> have it. The hypersaline freezing model has the problem
>> of fresh water layering in the Arctic. The Arctic water
>> is typically much fresher than the North Atlantic water
>> because the input of rivers in the Arctic so ice formation
>> mostly does not make Arctic surface water sink to the
>> bottom. Cooling of salty Atlantic water by cold Arctic air
>> creates dense water that sinks.
>
>Tree-hugger:

Me? I like open space.

> 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.

> 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.

>
>> 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. You
could start with looking at the projections of the IPCC and finding
problems for yourself. I don't want to answer this question directly
because I am working on ideas that are unpublished (and probably
rightly so).

http://www.ipcc.ch/

>
><snip>
>> > I have serious problems with their global current diagram,
>> >which would make the Califormia Current the product of
>> >upwelling, and ignores the formation of Deep Water
>> >in the Antarctic.
>> >
>> Hmmm...I thought the upwelling was a product of the current.
>
> Upwelling off the California coast, you mean?
> This study, ref'd by Haug's most recent _Nature_ article,
>describes it as being "offshore windstress-curl-driven".

The curent is wind driven and the curl relates to upwelling below the
surface layers.

>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.

>"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.

>
>Nature 429, 263 - 267 (20 May 2004); doi:10.1038/nature02567
>
>Regional climate shifts caused by gradual global cooling in
>the Pliocene epoch
>
>ANA CHRISTINA RAVELO, DYKE H. ANDREASEN, MITCHELL LYLE,
>ANNETTE OLIVAREZ LYLE & MICHAEL W. WARA
>
>> ><snip>
>> It's really hard to get a halocline where the water is
>> upwelling, which I thought they wrote the NPac was doing.
>
> Yes, it _was_, until the global conveyor was "short-
>circuited", allowing the halocline to develop in the NPac.
> This was supposedly the result of the Gulf Stream bringing
>warm water to the North Atlantic.

That is the THC!

> That meant more evaporation in the belt of the Westerlies,
>and so more precipitation in Russia, and so more fresh water
>entering the Arctic Ocean from Siberian rivers.
> The fresher Arctic water was easier to freeze, so the
>Arctic Ocean acquired a cover of sea ice.

Yep..the THC causes global cooling by bring warm water to the far
North Atlantic.

> 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.

> (Of course, the NADW would have had to acquire buoyancy
>along the way, either by dilution with less-salty water, or by
>warming.)
>
Yes. Or by upwelling in the ACC.

> 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.

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.

>
> Graphically shown here (push the numbered buttons):
>
>http://oceanusmag.whoi.edu/v42n2/haug-en4.html
>
> 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.

>
>> > What? Now the freshening of the North Pacific
>> >is an effect, not a cause, of Northern Hemisphere
>> >Glaciation?
>> > This conflicts directly with Haug's article in _Nature_.
>> > I don't get it.
>>
>> I'm not sure any of them get it. None of these folks seem to
>> get the basic thermodynamics of the THC. I need to take a
>> better look at the articles because what I have seen here
>> doesn't make much sense.
>
> The text of the relevant "news and views" commentary in
>_Nature_ is copied at the bottom of this post, for your
>edification and enjoyment.
>
>> ><snip>
>
>> >Still confused,
>> >Daryl Krupa
>>
>> I'm still confused too. I think that the confusion
>> reflects the inadequacies of the models & explanations
>> provided by the authors.
>
> Indeed (re: the explanations).
> In Haug, etc.'s latest article, they repeat this
>interpretation that appeared in the conference abstract:
>
>"However, the onset of Northern Hemisphere glaciation
>has proved to be inconsistent with ideas regarding the
>water vapour requirement 3, 4. It has been suggested that
>glaciation began in response to increased North Atlantic
>Deep Water formation and the flow of warm Gulf Stream
>waters into the high-latitude North Atlantic, associated
>with the closure of the Panama seaway 5, 6. However, recent
>studies show that this closure and associated changes in
>North Atlantic circulation occurred 4.6 Myr ago, well before
>the onset of intense Northern Hemisphere glaciation 4, 5."
>
> Their ref. 5 is a 4-page article in _Nature_ magazine from
>1998 (see ref. below).
> Their ref. 4 is Ravelo, et. al (2004), as above.
> Ravelo, et al. does not say that the Panama seaway closed
>at 4.6 Myr ago; it says that the "associated changes"
>occurred later than that:
>
>"Between 4.5 and 4.0 Myr ago, a marked shift in surface-water
>hydrographic gradients between the Pacific and Caribbean
>and between the Caribbean and the western tropical Atlantic,
>shoaling of the thermocline in the east Pacific, and
>circulation changes in the Atlantic, were possibly forced by
>tectonic event(s) (for example, restriction of the Panamanian
>or Indonesian seaways)."
> Re: restriction of the Panamanian seaway, they refer to a
>4-page article from 2001, in _Geology_ magazine, by Haug.
> In citing Ravelo, et al., Haug is being self-referential,
>by a circumlocutical path, which I suppose might be thought
>appropriate, given the ocean-conveyor subject matter ...
>
> 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. They don't give
>any generating factor for NPac stratification. They just say
>this about the onset of NPac stratification, which implies
>that NPAc stratification is _both_ cause and effect of NHG:
>
>"The close association of subarctic Pacific halocline formation
>with major Northern Hemisphere glaciation as well as the abrupt
>and dramatic nature of both changes suggest a positive feedback
>between the two.
>We have previously focused on how climate cooling increased the
>vertical stability of the North Pacific 13, 14.

>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.

> Ref. 13 is Haug, et al. (1999), and ref. 14 is Sigman, et al.
>(2004)
>(see below).
> There is only one mention of the Gulf Stream in Haug, et al.
>(2005), and every mention of the Atlantic is accompanied by a
>description of the inadequacy of explanations related to North
>Atlantic conditions in explaining the onset of NHG.
>
> I really don't see how
>changes in North Atlantic circulation
>could be connected to
>the initiation of NHG by NPac stratification
>as described in Haug, et al. (2005).
> 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.

>
> So, while we might now know where the moisture for ice
>accumulation in North America came from (not that there was
>any serious doubt), we still do not know why that moisture
>suddenly became available at about 2.7 Ma, so
>we still do not know why the North Pole is frozen, and so
>Rosell's claim,
>"Scientists discover why is the North Pole frozen",
>is still bogus.

Correct.

>
> But Thanks very much, George (the first) for setting me
>on the track of finding the answer to the question,
>"Eh! Paisan! w*********withyou! Eh!"
>
>Less puzzled, now, I think (maybe),
>Daryl Krupa
>
>-----------------------------------------------------
>[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
>
>In the Northern Hemisphere, large-scale glaciation was
>initiated comparatively recently. Paradoxically, it
>seems that the trigger was a seasonal warming of the
>sea surface in an upwind oceanic region.
>
>Over the past 50 million years, the Earth's climate
>has been cooling. Although Antarctica has been
>glaciated for at least the past 35 million years,
>large ice sheets did not appear in the Northern
>Hemisphere until about 2.7 million years ago.
>Earth scientists largely agree that overall climate
>cooling is associated with decreasing levels of carbon
>dioxide in the atmosphere, and that ice sheets can
>only grow if sufficient moisture is available and
>winter snow survives the summer heat. But what
>triggered the onset of the ice ages 2.7 million years
>ago? Explanations have focused on continental
>temperatures, with identification of potential
>moisture sources from the Atlantic, but there
>remain many open questions.
>
>Haug et al. (page 821 of this issue) contribute an
>important piece to the ice-age puzzle.
>Geochemical evidence suggests that, 2.7 million years
>ago, the seasonal temperature contrast of the subarctic
>Pacific Ocean sea surface became larger as summers
>warmed and winters cooled.
>Warmer summer sea-surface temperatures result in a
>warmer atmosphere that can hold more moisture.
>Like a snow gun blasting away at ski slopes, westerly
>winds blow the moisture onto the cold North American
>continent where it falls as snow and accumulates as ice.
>
>Haug et al. have combined geochemical expertise with
>numerical modelling to present an integrated approach to
>the origin of the ice ages.
>Evidence comes from the floor of the subarctic Pacific
>Ocean, on which the remains of certain species of marine
>plankton (diatoms, coccolithophores and foraminifera)
>have accumulated over time.
>The primary evidence for summertime warming 2.7 million
>years ago stems from the biochemistry of coccolithophores,
>which varies according to temperature.
>Augmenting this well-established index are the 18O/16O
>ratios in the siliceous tests of diatoms, a comparatively
>more complex measure of palaeotemperatures.
>
>At first glance, the results from these two recorders
>contrast with other climate indicators in this region.
>Foraminiferal 18O/16O ratios - a classical indicator -
>from the same deep-sea sediments suggest sea-surface
>cooling 2.7 million years ago.
>This particular evidence is corroborated by perhaps the
>most intuitive indicator of climatic cooling, an increase
>in the amount of debris of continental origin delivered
>to the site by icebergs.
>
>How can these apparently contradictory observations be
>reconciled? Haug et al. point to seasonal changes in
>the biological communities of the subarctic Pacific
>Ocean where, in modern times, different plankton
>communities populate the various seasons.
>Coccolithophores and those species of diatoms used for
>the geochemical analyses prefer the warm ocean surface
>of late summer and autumn. The particular foraminiferan
>species used for analysis, on the other hand, are more
>prolific during late winter and spring when the sea
>surface is fertile due to mixing with deeper, colder,
>nutrient-rich water.
>
>Thus the two seemingly opposing temperature trends
>2.7 million years ago simply reflect an increase in
>seasonality in the subarctic Pacific Ocean, which is
>consistent with other reconstructions of events in the
>North Pacific Ocean.
>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.

>What, then, caused the sudden increase in late summer
>temperatures?

Incrreased productivity of Coccolithophores could have another
explanation than temperature increase such as the same temp with
increased nutrients.

>To answer this question, Haug et al.
>refer to the physical properties of sea water itself.
>Water has a high heat capacity, which means that the
>surface ocean remains warm long after overlying air
>and adjacent land masses have cooled.
>If there is mixing of the surface ocean with deeper
>and cooler water, however, surface waters cannot warm up.
>This was the situation before 2.7 million years ago,
>evidence for which comes from the high accumulation
>rates of diatom skeletal remains at the study site,
>implying vigorous diatom productivity in the overlying
>sea surface and therefore a continuous supply of nutrients
>from deeper waters.
>
>At 2.7 million years ago, the abundance of diatom remains
>plummets, suggesting a decrease in the nutrient
>availability, like that brought about by the sea surface
>being cut off from the deeper ocean, at least on a
>seasonal basis.

On a seasonal basis doesn't cut it. Are there varve like seds? I
doubt it.They need to look at total production.

>At the same time, the reduction in vertical mixing allows
>the sea surface to warm.
>Thus the development of a seasonally layered, or stratified,
>surface ocean 2.7 million years ago, which was probably a
>regional response to the large-scale climatic changes at
>this time, allowed late summer/autumn warming of the sea
>surface and provided a moisture source for ice growth.

Npac warming delivering moisture to Siberia? Not Much. The NPac
water vapor gets squeezed out in the Coast Ranges and Rocky Mts. and
returned to the NPac via rivers. Look at modern ocean salinity
profiles.
>
>Haug et al. test the interpretations of the
>geochemical records with a suite of numerical
>computer-model experiments.

And for this bull*** they get published and cited. Bull*** with
computers is still bull***.

> The simulated ocean is
>'stratified' and 'destratified' to determine whether
>this mechanism can account for the geochemically
>derived changes in temperature. And it can. The
>stratified model state produces more extreme seasons
>and a larger North American ice *** than does the
>destratified model.

They never showed that stratification occurs or gave a good model of
how it would work, but they can show what effects it might have if it
happened. That's BS.

>
>This is an exemplary study.

<Insert science here>

> The individual climate
>indicators may not have withstood the uncertainties
>and assumptions that limit each of them,

Then????

>but put
>together by Haug et al.

The uncertainties aren't reduced one iota.

>they tell a cogent story of
>the origin of the ice ages.
>

<Please send more money>

_g

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