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Re: [Phys-l] global temperatures



kyle forinash wrote:
HI

Some factoids (mostly from the IPCC). Although the total annual average insolation remains constant for the earth over hundreds of thousands of years (even including orbit changes- and changes in sun intensity occur much slower), the LOCAL change at 60deg latitude is a seasonal variation of around ~400W/m^2.
Hmmmm...let's see: the overhead insolation at the equator - let's call it 700 W/m^2
So at 60degNorth, the insolation would be 700cos(60-23) = 569 W/m^2 in Summer,
and 700cos(60+23) = 85W/m^2 in Winter.
The LOCAL seasonal variation at 60 degN would be 569 - 85 = 484W/m^2
The LOCAL diurnal variation is 569 W/m^2 in Summer, and 85W/m^2 in Winter.

....in other words, I don't get it - so I am missing something??

Brian W