Robert I Ellison wrote:
> Fo you take me for an idiot? You don't read anything I say. I gave
> you the bloody IPCC definition of weather as chaotic and you waffle on
> about me somehow thinking this is a surprise.
Actually, you wrote:
"... Climate, however, is seen by the IPCC as an
average of weather – the unstated underlying assumption is that the
climate is not a complex and dynamic (chaotic) system and that there
is therefore an average climate state..."
> We barely know what ENSO was doing 400 years ago - what the hell has
> this to do with glacials - and only well for the past 60.
Over the past 10,000 years or so, the paleo data shows that the global
average temperature has remained within a rather narrow band. Going
back further in time, to the LGM, the average temperature appears to
have been about 5-6C lower, i.e., not a great change. Of course, over
short time periods, within the past 10,000 years, there have been
episodes of variation in temperature, but there is also evidence that
these changes were the result of known impacts of events, such as
volcanic eruptions, which are EXTERNAL to the climate system. The
glacial-interglacial cycles are thought to be forced by EXTERNAL
variations in solar energy flows. Thus, when discussing the climate
system and the INTERNAL variation, one can not ascribe all the
variation to INTERNAL CHAOTIC processes. The abrupt changes of
greatest impact, such as the Younger-Dryas period, were due to
situations which do not exist today and thus can not be expected to
occur in the near term, if I understand the paleo data.
>.....I am
> talking about obvious abrupt change in the instrument record - in both
> surface and ocean temperature. I referenced the US Nationl Academy of
> Sciences - 'Abrupt Climate Change: Inevitable surprises' which
> discusses both paleoclimatic and modern changes. I referenced 2 among
> many per reviewed studies - and you - and those that specifically and
> numerically identify abrupt change in the instrumental record and as a
> result of ENSO, the PDO, the NAO and the PNA - AND YOU UTTERLY MISS
> THE POINT AGAIN and snidely suggest that I supply some science. As if
> I have not.
[cut]
See above comment
> Chaos is a caracteristic of complex and dynamic systems - such as
> computer programs using the partial differential equations of fluid
> motion. Skill of modellers for God's sake. They bifurcate - jump
> into different states entirely with inputs within the realm of
> plausibility - just as Edward Lorenz's 1960's convection model did.
> Then these skillfull modellers chose one result that seems about
> right. If you don't understand this about models you understand
> nothing at all.
Except for the 8200 year BP event, I know of no example of a large
scale, abrupt change in global average temperature since the end of
the Y-D. And, again, both events appear to have been the result of
situations which do not exist today, that is, the flooding of the
North Atlantic and Nordic Seas due to the draining of large paleo
lakes formed as the glaciers retreated.
Yes, the ocean's mixed layer is typically about 100 meters thick.
And, how did all that cold water below actually get there? Well, it's
formed by sinking of waters at high latitudes via the THC. The warmer
waters can not sink, due to their lower salt content and higher
temperatures, which result in a lower density.
> You contradict yourself. Climate both evolves slowly and in the
> second paragraph abruptly? There are lots of factors other than north
> Atlantic THC - dust, cloud, ice and the entire bloody Southern
> Hemisphere. Get your head out of your proverbial and read a litle
> better, deeper and wider.
There is a component of the THC which acts around the Antarctic,
associated with the yearly advance and retreat of sea-ice. The
deepest waters of the Atlantic and Pacific are formed this way.
> BTW - the 'transport index (bottom panel) estimates the strength of
> the baroclinic gyre circulation in the North Atlantic, or the strength
> of the Gulf Stream and North Atlantic Current system. The units (Mtons
> s-1) are within a few percent of the volumetric unit of transport
> (Sverdrups = 106 m3s-1). It is calculated from the difference of the
> potential energy anomalies (PEA) near Bermuda and in the Labrador
> Basin (top two panels).
>
> The evolution of the index from 1950 through 2000 shows a circulation
> reducing through the low NAO period in the 1960s, then strengthening
> during the period of persistently high NAO over the next 25 years,
> reaching a peak in the mid-1990s. They found that the timing and
> mechanisms associated with PEA changes in each gyre varied, and were
> dependent on both locally and remotely-forced changes in the ocean
> (see paper for details).'
>
>
http://ioc-goos-oopc.org/state_of_the_ocean/sub/berm_lab_trans.php
>
> I have provided this link previously as well - some of this is very
> difficult science unlike my attempts at science communication. Do try
> to pay attention.
That index appears to describe the gyre circulation in the North
Atlantic Sub Polar Gyre, which has a strong wind driven component.
The Gulf Stream is a wind driven current, which feeds into the North
Atlantic Gyre. However, the THC appears to be located in the Nordic
and Labrador Seas, with some fraction also occurring in the Arctic
Ocean. this is not the same geographical location as the NA Sub Polar
Gyre.
I think you are missing the importance of the THC as a process of
longer time scales with results which appear to dominate the long term
record. There are also short term fluctuations in the THC, such as
that which may have resulted from the Great Salinity Anomaly, starting
in the early 1970's. During the early 1980's, there is evidence that
the THC sinking in the Greenland Sea ceased. I suggest that the
cooler winter conditions around the North Atlantic of that period may
have been the result. My perception (based on satellite evidence over
the last few years), is that the THC may have again weakened in the
Nordic Seas. The cause this time might be the known freshening of the
Nordic Seas as the sea-ice yearly melt has strengthened, allowing more
fresh water to enter the Greenland Sea thru the Fram Strait. That we
did experience a bit colder weather last winter in the Eastern US may
have been the result, but, sad to say, I can not point to any
acceptable proof.
E. S.