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>> to go from a claim 4 years ago that during the last 60 years we were
>> seeing a 1000 year high in sunspot activity, to a bottom of cycle 50 year
>> (and almost 100 year) record period without any sunspot activity at all,
>> seems strange, at least.

> This would be exactly the expected symptoms from a small rise in amplitude
> of the sunspot cycle.  It would be very strange if such a large scale
> oscillation didn't vary in amplitude occasionally.  Put another way, it
> would be silly to expect it to be a pure sine at just the major observed
> frequency.

It's far more complex than a simple "oscillatory" signal - quite un sine
like in behaviour. There are a numnber of major mechanisms at work and none
are well understood. For example, one major main stream theory is of a
"solar dynamo" generating vast currents, coupled with very low velocity
mechanical shock waves (of the orders of a few metres per second) which
travel between the sun's surface and denser inner regions and ... *OR* /
*AND* planetary motion sets up gravitational waves in the sun which ...
*OR*... .

> Regardless of the exact mechanism, surely there are multiple
> feedback paths at work.  That makes a pure sine extremely unlikely.  Most
> likely there is even a chaotic contribution, much like our own (and much
> more pronounced) El Nino for example.

So, yes. And the effects of the sunspot variations on earth's heating is
uncertain. Solar irradiance variations are believed to be relatively small
and have apparently been increasing by about 0.5% per century in recent
times. But the Pacific and Atlandic decadal oscillations are both entering a
downturn at the same time as the sunspot number has about reached zero,
whereas in the 1950's we had low sunspot numbers but not the same
correlation with the ocean cycles. The more severe than usual Northern
winter (they tell me) and better than expected polar ice refreeze seems to
be due at least to the ocean cycles if not to the sunspot variations, yet at
least. A 'popular' theory is that low sunspot number reduces gamma ray
deflections which increase atmosperic aerosols which increase cloud which
increases albedo and recuces net insolation which ... . But that is just yet
another theory with less observational support than is comfortable. It
should quite possibly become evident quite quickly (say the next few years)
whether a major change is in the offing. Carbon trading may be even more
lucrative 10 years from now - but they'll pay you to burn it - or best of
all to manufacture and release methane :-). Yes - that's a flippancy, but it
really is highly uincertain what's happening, and if the PDO, ADO and
sunspot number all decide to gang up on us we could be in for some very cold
winters indeed. Shovelling 3000 feet of ice off a New york sidewalk would be
challenging.


  Russell

<C9829E27E69D4D9CAF042CE4855D7AF1@gaddiel> 7bit

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