Eric,
I am indeed a civil engineer with a masters in environmental science.
My basic interest is in hydrological science - rainfall and runoff,
water quality, fluvial systems, etc - all of which of course involve
ocean states and atmospheric transport. I have been diligently
searching for an answer to Australian hydrological variability for
more than 20 years. I have found it but I don't know what it means or
what to do with it. Frustrating.
When you say correlation you are thinking in terms of cross
correlation of TSI with temperature for instance - a forcing with an
effect. In the Tsonis case the correlation is of the topological
'distance' between indices. It is more like the autocorrelation
technique used by Dakos et al to examine abrupt climate change in the
past. Autocorrelation is used to discern a repeating pattern in a
signal.
'Slowing down as an early warning signal for abrupt climate change':
Vasilis Dakos, Marten Scheffer, Egbert H. van Nes, Victor Brovkin,
Vladimir Petoukhov, and Hermann Held
14308–14312:PNAS:September 23, 2008:vol. 105:no. 38
You reject complex system dynamics but I quote the IPCC and the NAP as
well in support of the view of climate as a dynamic complex system on
all scales from ENSO to ice ages and beyond. But these are just words
and one needs something of an understanding of the background theory
to understand what these words mean in context. Chaos theory and
strange attractors are indeed central to concepts of abrupt and large
climate change.
I don't say anything about the future in black and white terms - but
the indices I mentioned in response to your question have implications
for climate and weather. For instance, the SAM index and the NAO
index have implications for the tracks of storms spinning off the
polar vortices. The PDO is associated with multidecadal modulation of
ENSO - with obvious implications for climate.
There are a large number of ocean/climate indices -
http://ioc-goos-oopc.org/state_of_the_ocean/all/ - these allow
qualitative judgements about regional rainfall and climate on
interrannual to multidecadal scales to be made without considering
solutions to the Navier-Stokes partial differential equations.
I guess you are the 31.07 year old software engineer known as E-dawg?
I guess that your problem is not with the idea under discussion of
abrupt climate change - so much as what no warming for a decade or 2
will do with what's left of the public debate.
Impossible to predict - the risk of abrupt climate change would
ideally lead to decarbonising economies (and I suggested some means of
doing this that avoids much of the cap and trade downside) but I very
much fear that scientific arrogance, extreme scenarios such as the one
under discussion and green overreach has lost the public relations
battle for a generation or 2.
Regardless of my views - there is no need to be rude and
aggressive.
Cheers
Robbo
On Jan 9, 8:30 am, Eric Swanson <[email protected]> wrote:
> Robbo,
>
> With all due respect to you and your civil engineering experience, I
> think you have missed my point.
>
> Robbo wrote:
> > The Tsonis et al theory of ocean/climate states
> >http://www.nosams.whoi.edu/PDFs/papers/tsonis-grl_newtheoryforclimate...)
> > confirms that climate on decadal timescales is an emergent property of
> > complex and dynamic Earth systems. "You go from a cooling regime to a
> > warming regime or a warming regime to a cooling regime. This way we
> > were able to explain all the fluctuations in the global temperature
> > trend in the past century," Anastasios Tsonis said.
>
> From which you conclude:
>
> > The methodology has nothing at all to do with correlation or causality.
>
> But, as Tsonis states:
>
> "[5] Figure 1a shows the distance as a function of time for a window
> length of Dt = 11 years, with tick marks corresponding to the year in
> the middle of the window. The correlations (and thus distance values
> for each year) were computed based on the annual-mean indices
> constructed
> by averaging the monthly indices over the period of November–March.
> The dashed line parallel to the time axis in Figure 1a represents the
> 95% significance level associated with the null hypothesis that the
> observed indices are sampled from a population of a 4-dimensional AR-1
> process driven by a spatially (cross-index) correlated Gaussian noise;
> the parameters of the AR-1 model and the covariance matrix of the
> noise are derived from the full time series of the observed indices.
> This test assumes that the variations of the distance with time seen
> in Figure 1a are due to sampling associated with a finite-length (11-
> yr) sliding window used to compute the local distance values.
> Retaining overall cross-correlations in constructing the surrogates
> makes this test very stringent. Nevertheless, we still find five times
> (1910s, 1920s, 1930s, 1950s, and
> 1970s) when distance variations fall below the 95% significance level.
> We therefore conclude that these features are not likely to be due to
> sampling limitations but they represent statistically significant
> synchronization events."
>
> In other words, the "proof" of their technique is statistical
> correlations. And, they use an 11 year moving average to define their
> indices. Moving averages induce spurious "signals" into a time series
> thru aliasing. I think that using a moving average thusly may
> invalidate their results.
>
> > The NAO is strongly negative and this may be a decadal variation
> > leading to very much cooler conditions over the NH. The Bermuda-
> > Labrador Basin Transport Index is near it's low point in the very
> > limited record. A strong cooling - as is being seen in the current NH
> > winter - may continue. It has happened in the past century - it is
> > very possible that NH (particularly US, northerly regions of Europe
> > and the Arctic) temperatures will fall strongly over the next decade
> > or 2.
>
> This does not answer my question. You asserting some future course
> for the weather with no link to causality, with no mention of the
> historical forcings. To me, such a claim is poor science.
>
> Think of it this way. Build a time series of hourly temperature for
> summer. Now, try and "predict" the next full year's temperatures
> using Tsonis approach. Will you be able to come anywhere near the
> temperatures in winter? Without a full understanding of the rest of
> the yearly cycles, such as the yearly solar cycle, you can't come
> close to reality. Even with several years of hourly data, you will
> still find that such a prediction will miss reality quite a few
> times.
>
> > The indices are not indicative of any causal agency but do capture
> > modes of climate variability and associated effects. It is like
> > saying that the PDO and ENSO cause changes in decadal patterns of
> > rainfall in Africa, Australia, Asia, the USA and South America. But
> > the underlying cause is not PDO or ENSO but the dynamics of climate as
> > a forced nonlinear oscillator expressing in part as the PDO and
> > ENSO.
>
> You are assuming that ALL the variation is captured by these indices
> and that this variation is the result of the presumed internal
> oscillators. The indices don't cause anything, they are just
> indicators of the changes in what is measured. They are not
> predictive, since they are not based on any changes which may be
> occurring in the external forcing, such as solar variability, volcanic
> eruptions, additions of greenhouse gases, etc. Tsonis et al. do not
> even attempt to remove the external forcings from their indices before
> concluding that they have a handle on the internal oscillations.
>
> > Chaos theory confirms the reality of the risk of serious climate
> > change (either warming or cooling) in response to greenhouse gas
> > forcing. In the short term however (a decade or so), surface
> > temperature may continue on the current trajectory of a lack of
> > warming.
>
> Again, you make a projection of the future climate based on an
> assertion that chaos "theory" will provide a framework to make this
> projection. At the moment, it's not clear what might be causing the
> slow down in warming, from my limited understanding. It might turn
> out that the increased emissions of sulfates and other forms of air
> pollution in China and India may be the reason or it may also be that
> there is a reduction in the THC in the North Atlantic as a result of
> Global Warming. We know both are happening. Can your chaos theory
> pick out these possible causes? I think not, since the process is
> backward looking and ignores the various forcings.
>
> > Most people always think they have the complete and unvarnished
> > truth. The usual state of the human condition is more or less
> > complete ignorance. Indeed the best definition of science I know of
> > is that science is exploration at the boundary of human ignorance. It
> > is a hard lesson learned time and time again.
>
> Sounds reasonable to me. Try telling that to the religious
> fundamentalists. So, what does that have to do with your continual
> ranting about Tsonis et al.? You are acting like a troll, repeatedly
> posting your latest world view for ego gratification or what ever
> reasons. Perhaps you should take a bit more time to study the
> atmospheric sciences before you start jumping up and down and shouting
> "This is IT!!"
>
> E. S.
> ---
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