Re: [asa] New Climate Model, Short-Term Cooling in a Warmer World

From science mag:

"To take account of such ocean-driven natural variability, Keenlyside and
his colleagues began their model's forecasting runs by giving the model's
oceans the actual sea surface temperatures measured in the starting year of
a simulation. Providing the initial state of the ocean doesn't make much
difference when forecasting out a century, so long-range forecasters don't
usually bother. But an initial state gives the model a starting point from
which to calculate what the oceans will be doing a decade hence and
therefore what future natural variability might be like."
In other words, long-term predictions are relatively insensitive to initial
conditions so there's no need to take the time to load them. Short-term
fluctuations are, understandably, more sensitive to initial conditions. I
think it does contribute to an increase in confidence of the models.

Randy

----- Original Message -----
From: "Dave Wallace" <wdwllace@sympatico.ca>
To: "ASA" <asa@calvin.edu>
Sent: Friday, May 02, 2008 10:40 AM
Subject: [asa] New Climate Model, Short-Term Cooling in a Warmer World

> http://www.nytimes.com/2008/05/01/science/earth/01climate.html?_r=1&oref=slogin
>
> One of the first attempts to look ahead a decade, using computer
> simulations and measurements of ocean temperatures, predicts a slight
> cooling of Europe and North America, probably related to shifting currents
> and patterns in the oceans.
>
> The team that generated the forecast, whose members come from two German
> ocean and climate research centers, acknowledged that it was a preliminary
> effort. But in a short paper published in the May 1 issue of the journal
> Nature, they said their modeling method was able to reasonably replicate
> climate patterns in those regions in recent decades, providing some
> confidence in their prediction for the next one.
> ============
>
> As best I can tell what they are doing is using actual ocean temperature
> measurements to refine the models. Seems to me such actuals should have
> been used all along and does little to increase confidence in the models.
>
> Dave W (ASA)
>
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Received on Fri, 2 May 2008 11:23:26 -0400