On Jan 19, 6:22 pm, "[email protected]" <[email protected]>
wrote:
> > Are you sure what you're speculating about? The distributed computing
> > client receives seed data and runs a model based on starting parameters.
> > It is not modified with additional data while it runs. So I don't believe
> > I'm convinced that such a model would likely diverge at the current date.
>
> The problem is that the forcing isn't known well for the 20th century.
> That's why climate sensitivity is not well constrained by 20th century
> data.
>
> The only way to make model runs of the 20th century closely match
> reality is by choosing corresponding forcings, that is for high
> climate sensitivity high aerosol forcing, and for low climate
> sensitivity low aerosol forcing.
>
> http://climateprediction.net/content/public-presentations-talks-and-p...
> (Myles Allen, What can be said about future climate? Quantifying
> uncertainty in multi-decade climate forecasting, Harvard University,
> February 2008.) slide 7
Per,
Let me put it aother way.
You are correct that the ClimatePrediction models are not tweaked
during the initial phase to make them match the current climate, but
if at the end of that run they do not match then they are discarded,
and the second phase is aborted. So effectively, they are using
tweaked parameters - ones that fit the current climate.
The results from the third phase vary by a large degree, despite the
fact that they the models have been selected. They range from 1.5C to
over 10.0C, so since only one correct answer, there must be an awful
those models giving the wrong answer.
Cheers, Alastair.
--
You received this message because you are subscribed to the Google Groups
Global Change ("globalchange") newsgroup. Global Change is a public, moderated
venue for discussion of science, technology, economics and policy dimensions of
global environmental change.
Posts will be admitted to the list if and only if any moderator finds the
submission to be constructive and/or interesting, on topic, and not
gratuitously rude.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/globalchange
