Re: The Western Interior Seaway (and computers)

[Phil Bigelow <bigelowp@juno.com>]

Good point.  There is not much physical evidence (none?) for a Mesozoic
arctic sea ice sheet, so if there was a WIS dynamo it may have been a
very weak one.  A sea ice sheet might be a feature that a computer model
could predict (or eliminate as a possibility).  If it existed, perhaps
the sea ice
was only a seasonal feature.

Our current Arctic Ocean sea ice sheet is eroding at an alarmingly rapid
rate.  How small can it get before the dynamo shuts down?

<pb>
--

On Wed, 29 Jun 2005 05:45:11 +0100 Aidan Karley
<aidan_karley@yahoo.co.uk> writes:
> In article <20050628.130115.-985265.4.bigelowp@juno.com>, Phil 
> Bigelow 
> wrote:
> > I was thinking way back to my Geo. 101 lab days.  Cold water at 
> the poles
> > sinks, drawing the warm water from the equator northward to take 
> its
> > place.  The cold water then upwells near the tropics to begin the 
> process
> > over.
> >
>        AIUI, the driver process is the change in sea-water density 
> caused 
> by cooling and by the removal of significant fresh water to form 
> pack ice. 
> There's also a simple thermal contribution too, but it's less 
> important as 
> indicated by the Heinrich events (Laurentide/ Greenland deglaciation 
> yields 
> lots of fresh-water runoff to the North Atlantic, which inhibits the 
> 
> sinking of water in the NE Atlantic and shuts down the system. 
> Seabed 
> sediment data indicates this happens on the timescale of years not 
> decades, 
> providing some justification for the (allegedly) atrocious 
> climate-foul-up 
> film of last year. [sorry, brain has drawn a blank on it's name. 
> It's late 
> here. Whatever.])
> 
> > Did hydraulic
> > shear occur at mid-depth between the northward-flowing warm water 
> and the
> > southward flowing colder water?
> >
>        Well it happens these days, so presumably it could have 
> happened in 
> the past.
>        
> -- 
>  Aidan Karley,
>  Aberdeen, Scotland,
>  Location: 57°10' N,  02°09'  W (sub-tropical Aberdeen), 0.021233
>  Written at Wed, 29 Jun 2005 04:07 +0100
> 
> 
> 
>               
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