Re: [asa] Crop Yields Face Non-Linear Effects Due to Climate Change

From: Bill Powers <>
Date: Fri Aug 28 2009 - 09:13:08 EDT

As you say, it is good to see such model sensitivity studies using
numerical models. Indeed, it is my view that this is the real value of
such models, and not as reliable predictors of future weather.

Regarding sensitivity, I hope that the numerical modelers have
investigated the sensitivity of their own code to small variations,
including numerical roundoff. Nonlinear codes are notorious for producing
vastly different results just by changing the order in which factors are
multiplied, etc.


   On Thu, 27 Aug 2009, Schwarzwald wrote:

> Also from Physorg:
> Study: Small fluctuations in solar activity, large influence on the climate
> *( -- Subtle connections between the 11-year solar cycle, the
> stratosphere, and the tropical Pacific Ocean work in sync to generate
> periodic weather patterns that affect much of the globe, according to
> research appearing this week in the journal Science. The study can help
> scientists get an edge on eventually predicting the intensity of certain
> climate phenomena, such as the Indian monsoon and tropical Pacific rainfall,
> years in advance.*
> An international team of scientists led by the National Center for
> Atmospheric Research (NCAR) used more than a century of weather observations
> and three powerful computer models to tackle one of the more difficult
> questions in meteorology: if the total energy that reaches Earth from the
> Sun varies by only 0.1 percent across the approximately 11-year solar cycle,
> how can such a small variation drive major changes in weather patterns on
> Earth?
> The answer, according to the new study, has to do with the Sun's impact on
> two seemingly unrelated regions. Chemicals in the stratosphere and sea
> surface temperatures in the Pacific
> Ocean<>respond during solar
> maximum <> in a way that amplifies
> the Sun's influence on some aspects of air movement. This can intensify
> winds and rainfall <>, change sea
> surface temperatures and cloud cover over certain tropical and subtropical
> regions, and ultimately influence global weather.
> "The Sun, the stratosphere, and the oceans are connected in ways that can
> influence events such as winter
> <>rainfall in North America," says
> NCAR scientist Gerald Meehl, the lead
> author. "Understanding the role of the solar cycle can provide added insight
> as scientists work toward predicting regional weather patterns for the next
> couple of decades."
> ---
> Interesting stuff. Glad to see impacts and effects of variables in earth's
> climate are being investigated all around.

To unsubscribe, send a message to with
"unsubscribe asa" (no quotes) as the body of the message.
Received on Fri Aug 28 09:14:01 2009

This archive was generated by hypermail 2.1.8 : Fri Aug 28 2009 - 09:14:01 EDT