Name the Major Flaw In This Signal Processing Analysis Probl

[Bret Cahill]

Play around with an O2 meter sometime.  Hold your breath until you
start to gag and get a reading.  It's nearly impossible to go below
14%.

It's not lack of O2 that causes you to gag, it's
build-up of CO2.

CO2 obviously builds up in the lungs of divers that swim straight down
on nothing but a breath of air. The record is something like a 100
meters straight down which is impossible just below the surface. Why
can a diver burn more calories at depth per breath of air with all
this CO2 that he couldn't do just below the surface?

None of this is an argument against carbon abatement or even natural
gas just that burning the H in hydrocarbons esp. in Nat. gas is
lowering the partial pressure of O2 as the C is increasing CO2.

Most animals are sensitive to even small changes in O2, especially if
it's over the entire life span. Studies have shown that people living
at altitude live longer so maybe deniers should try to spin the lower
partial pressure of O2 as one of the health benefits of burning
natural gas.

As a blue water fisherman / medical student said of the study, "yea,
sure, if you want to call being that far from the ocean that
'living'." You don't need a study or a medical background to know if
you reduce O2 to zero then heart disease and cancer rates drop to
zero.

The sea level rise from burning fossil hydrogen isn't a significant,
but since it is being cracked back to O2 more slowly than it is being
formed the drop in O2 partial pressure could become a concern, health
studies notwithstanding.


Bret Cahill

 

[Bret Cahill]

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh...

Bret Cahill

Use of Fourier analysis.

Most would go with the two higher frequencies.  The problem is
extrapolating off of the two cycles of the /1300 year frequency.

Bret Cahill

This is all bs

They claimed that their tree ring data reflected some of the recent
events documented in other places but then they include the un
collaborated 1/1300 year frequency like it means something.

Is it noise or signal?

They haven't even explained how they arrived at decomposition in Fig.
4

Everything is filtered except the three lowest frequencies.

The problem with high pass filtering to pre dynastic China periods is
you must wait 1300 years to determine if the lowest frequency is
noise.

That is not acceptable when it's clear that today's warming is /decade
and that CO2 is the major cause.

This may be more of a study to see what deniers will latch onto than
anything else.  Most Chinese scientists know this is junk science.

Bret Cahill

China still burns lots of coal

In the past Chinese climate scientists were independent of Beijing.
That could be changing.  China is ready to go to war for the oil in
the S. China Sea.

Burning coal is very very bad (and not just for CO2)

They are about to be joined by Ukraine (currently on the path to stone
ages converting industries from natural gas to coal and already denied
Kyoto's money  ...)

When it comes to preserving 02 levels by not burning fossil hydrogen,
natural gas becomes the worst offender.

Solar power is now dirt cheap.  They just need to convert to solar.

Bret Cahill- Hide quoted text -

- Show quoted text -

I don't have the figures but am pretty sure that burning natural gas
for heat is a LOT better than burning coal, from many perspectives,
CO2 including

The now standard residential high-efficiency natural gas furnace is
95% efficient and leaves almost no residue other than CO2, some CO and
water vapor

But it's lowering O2 levels.

Play around with an O2 meter sometime.  Hold your breath until you
start to gag and get a reading.  It's nearly impossible to go below
14%.

Converting steel industry to solar ???

Once a country has become sustainable it's not a big contributor.

Bret Cahill- Hide quoted text -

- Show quoted text -

Lowering O2 level in atmosphere is not a problem (for a foreseable
future)

We can only hope you are correct. The biosphere is a complicated
system. A tiny effect here can often turn out to be a big effect
there. Time and again climate scientists have been way too optimistic
on the speed of the warming and the impact on the biosphere from CO2.

Increasing CO2 level beyond 0.04% by volume is a major deal-

As far as we know at this time.


Bret Cahill

 

[AGWFacts]

On Sun, 11 Dec 2011 20:52:48 -0800 (PST), Bret Cahill
<BretCahill@peoplepc.com> wrote:

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-shows-shows-sun-controls-climate-temps-will-cool-til-2068/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+JoNova+(JoNova)&utm_content=Google+Feedfetcher

LOL! Good catch. The writer of the propaganda seems to believe the
central-eastern Tibetan Plateau is the entire planet, therefore
all of the scientists on the planet are wrong. Amazing. Funny,
too.


--
"I'd like the globe to warm another degree or two or three... and CO2 levels
to increase perhaps another 100ppm - 300ppm." -- catoni52@sympatico.ca

 

[AGWFacts]

On Mon, 12 Dec 2011 01:37:32 -0800 (PST), Rune Allnor
<allnor@tele.ntnu.no> wrote:

On Sun, 11 Dec 2011 20:52:48 -0800 (PST), Bret Cahill <BretCahill@peoplepc.com> wrote:

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-shows-shows-sun-controls-climate-temps-will-cool-til-2068/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+JoNova+(JoNova)&utm_content=Google+Feedfetcher


Bret Cahill

There is too little information to see exactly how
they have extrapolated the data, but I have no
problems accepting the main thesis of the piece.

The main thesis of the propaganda is that the central-eastern
Tibetan Plateau represents the entire planet. You don't see any
problem with that?

The hard part is to let go of the popular notion
that the past couple of decades' raise in temperature
is man-made.

All of the evidence says it is. Why would someone wish to "let go"
of the observed facts?


--
"I'd like the globe to warm another degree or two or three... and CO2 levels
to increase perhaps another 100ppm - 300ppm." -- catoni52@sympatico.ca

 

[Rune Allnor]

On 13 Des, 22:06, AGWFacts <AGWFa...@ipcc.org> wrote:

On Mon, 12 Dec 2011 01:37:32 -0800 (PST), Rune Allnor

all...@tele.ntnu.no> wrote:
On Sun, 11 Dec 2011 20:52:48 -0800 (PST), Bret Cahill <BretCah...@peoplepc.com> wrote:

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh...

Bret Cahill
There is too little information to see exactly how
they have extrapolated the data, but I have no
problems accepting the main thesis of the piece.

The main thesis of the propaganda is that the central-eastern
Tibetan Plateau represents the entire planet. You don't see any
problem with that?

Not really: Any claims to *global* warming should apply
to that area as well. If there is one area that fails
to comply with the dominant thesis, there might be others.
If these guys are any good, their journal article
will contain a good enough description of what they
did, so other researchers can

1) re-do their analysis on the same data
2) repeat the investigation in other areas.

I have seen severe criticisms of Mann et al, on the
basis that no one were able to reproduce the 'hockey-
stick' graph. Others being able to replicate the results
is one main divider between science and fraud.

The hard part is to let go of the popular notion
that the past couple of decades' raise in temperature
is man-made.

All of the evidence says it is. Why would someone wish to "let go"
of the observed facts?

The *facts* are that the present climate is warmer than
amere couple of decades ago. Any claims that the change
is *man-made* are speculation. As I said in an earlier
post, one can easily find data that show any co-variation,
like between population numbers of humans and storks.

The numbers are facts. Any claim that there is a cause-effect
relation needs to be justified.

Rune

 

[Rune Allnor]

On 13 Des, 22:59, Rune Allnor <all...@tele.ntnu.no> wrote:

On 13 Des, 22:06, AGWFacts <AGWFa...@ipcc.org> wrote:

All of the evidence says it is. Why would someone wish to "let go"
of the observed facts?

The *facts* are that the present climate is warmer than
amere couple of decades ago. Any claims that the change
is *man-made* are speculation. As I said in an earlier
post, one can easily find data that show any co-variation,
like between population numbers of humans and storks.

The numbers are facts. Any claim that there is a cause-effect
relation needs to be justified.

The baby-stork example is available on-line, in Amazon's
pre-view of the Box, Hunter & Hunter 2005 edition:

http://www.amazon.com/Statistics-Experimenters-Design-Innovation-Discovery/dp/0471718130/ref=sr_1_2?ie=UTF8&qid=1323814230&sr=8-2#reader_0471718130

Don't know how close one gets through that link, but it's
figure 1.3, page 8, under the Look Inside flag.

This is a standard text on data analysis, so it is
rather disturbing that somebody who claim affiliations
with IPCC (the email address you post from) don't
know this.

Maybe just as well you don't post under your real name.

Rune

 

[Bret Cahill]

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh...

LOL! Good catch. The writer of the propaganda seems to believe the
central-eastern Tibetan Plateau is the entire planet, therefore
all of the scientists on the planet are wrong. Amazing. Funny,
too.

True but irrelevant here where we humor his claim that his tree data
correlate well with the medieval warm period and other documented
events.

Here the problem is claiming a /1300 year frequency is signal when he
doesn't even have two periods of sampling time. To be somewhat sure
it wasn't noise would require waiting another 1300 years.

That doesn't get it when the ocean is rising 2 in every 13 years.


Bret Cahill

"I'd like the globe to warm another degree or two or three...  and CO2 levels
to increase perhaps another 100ppm - 300ppm." -- caton...@sympatico.ca

 

[Rune Allnor]

On 14 Des, 00:04, Bret Cahill <BretCah...@peoplepc.com> wrote:

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh....

LOL! Good catch. The writer of the propaganda seems to believe the
central-eastern Tibetan Plateau is the entire planet, therefore
all of the scientists on the planet are wrong. Amazing. Funny,
too.

Sure. The same argument works against claims the other
way, that are based on findings on the Greenland glacier
core samples: How would you justify a claim that local
findings are relevant on a global scale?

True but irrelevant here where we humor his claim that his tree data
correlate well with the medieval warm period and other documented
events.

And do contemplate what this means: *several* independent
data sets point in the same direction.

Here the problem is claiming a /1300 year frequency is signal when he
doesn't even have two periods of sampling time.  To be somewhat sure
it wasn't noise would require waiting another 1300 years.

Such a claim would be problematic if these data were
all there was. But since the authors compare their own
findings with other, independent data sets, they have
a substantially stronger case.

Rune

 

[Bret Cahill]

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh...

LOL! Good catch. The writer of the propaganda seems to believe the
central-eastern Tibetan Plateau is the entire planet, therefore
all of the scientists on the planet are wrong. Amazing. Funny,
too.

Sure. The same argument works against claims the other
way, that are based on findings on the Greenland glacier
core samples: How would you justify a claim that local
findings are relevant on a global scale?

True but irrelevant here where we humor his claim that his tree data
correlate well with the medieval warm period and other documented
events.

And do contemplate what this means: *several* independent
data sets point in the same direction.

That's irrelevate in this thread as the tree ring data is assumed to
be accurate.

Here the problem is claiming a /1300 year frequency is signal when he
doesn't even have two periods of sampling time.  To be somewhat sure
it wasn't noise would require waiting another 1300 years.

Such a claim would be problematic if these data were
all there was.

It's problematic even if the temperature/time graphs are taken as
accurate. That was the point of the OP.


There is no way to know if the < 2 cycles of the 1/1300 year frequency
are signal or noise. You have to wait a few thousand more years to be
sure.

There is no question climate scientists would like to low pass filter
but there just isn't any time.


Bret Cahill

 

[Bret Cahill]

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh...

Bret Cahill
There is too little information to see exactly how
they have extrapolated the data, but I have no
problems accepting the main thesis of the piece.

The main thesis of the propaganda is that the central-eastern
Tibetan Plateau represents the entire planet. You don't see any
problem with that?

Not really: Any claims to *global* warming should apply
to that area as well.

Actually part of the surface is _cooling_ as the rest is warming.

Sea level is the same way. In most places the sea level will rise but
in some it will drop.

Can you figure out why?


Bret Cahill

 

[Rune Allnor]

On 14 Des, 01:37, Bret Cahill <Bret_E_Cah...@yahoo.com> wrote:

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh...

LOL! Good catch. The writer of the propaganda seems to believe the
central-eastern Tibetan Plateau is the entire planet, therefore
all of the scientists on the planet are wrong. Amazing. Funny,
too.

Sure. The same argument works against claims the other
way, that are based on findings on the Greenland glacier
core samples: How would you justify a claim that local
findings are relevant on a global scale?

True but irrelevant here where we humor his claim that his tree data
correlate well with the medieval warm period and other documented
events.
And do contemplate what this means: *several* independent
data sets point in the same direction.

That's irrelevate in this thread as the tree ring data is assumed to
be accurate.

It's very relevant, as few if any data from outside lab
conditions can be taken at face value. If several
independent measurements point in the same direction,
that tends to be mutually supportive.

Here the problem is claiming a /1300 year frequency is signal when he
doesn't even have two periods of sampling time.  To be somewhat sure
it wasn't noise would require waiting another 1300 years.
Such a claim would be problematic if these data were
all there was.

It's problematic even if the temperature/time graphs are taken as
accurate.  That was the point of the OP.

The point is that you can not evaluate these data in
isolation; in that case they are just numbers. It is
only when they fit the big picture, already sketched
by other measurements, that they start making sense.

There is no way to know if the < 2 cycles of the 1/1300 year frequency
are signal or noise.  You have to wait a few thousand more years to be
sure.

So what? The FFT or periodogra or whatever is just
a mathematical method you can apply to the available
data.

This is what I have said throughout the whole thread:
The data themselves say nothing about what causes
them to look like they do. OK, the present data set
may or may not be subject to a 1300 year cycle.
That's not the point. The point is that the *present*
data, recorded over the past couple of decades, show
variation on a scale that is not at all unique for the
period and location under study.

There is no question climate scientists would like to low pass filter
but there just isn't any time.

Why would they? Just have a look at the data available.
As I said early on, the hard part is to let go of
mythlogy, vested interests and presuppositions.

Rune

 

[Michael A. Terrell]

fungus wrote:

You know how I know you don't have any real
arguments or evidence on your side?

Yes. You pull it out of your ass, like everything else you post.


--
You can't have a sense of humor, if you have no sense.

 

[fatalist]

On Dec 13, 3:31 pm, Jerry Avins <j...@ieee.org> wrote:

On 12/13/2011 2:35 PM, Bret Cahill wrote:





Play around with an O2 meter sometime.  Hold your breath until you
start to gag and get a reading.  It's nearly impossible to go below
14%.

It's not lack of O2 that causes you to gag, it's
build-up of CO2.

CO2 obviously builds up in the lungs of divers that swim straight down
on nothing but a breath of air.  The record is something like a 100
meters straight down which is impossible just below the surface.  Why
can a diver burn more calories at depth per breath of air with all
this CO2 that he couldn't do just below the surface?

None of this is an argument against carbon abatement or even natural
gas just that burning the H in hydrocarbons esp. in Nat. gas is
lowering the partial pressure of O2 as the C is increasing CO2.

Most animals are sensitive to even small changes in O2, especially if
it's over the entire life span.  Studies have shown that people living
at altitude live longer so maybe deniers should try to spin the lower
partial pressure of O2 as one of the health benefits of burning
natural gas.

As a blue water fisherman / medical student said of the study, "yea,
sure, if you want to call being that far from the ocean that
'living'."  You don't need a study or a medical background to know if
you reduce O2 to zero then heart disease and cancer rates drop to
zero.

The sea level rise from burning fossil hydrogen isn't a significant,
but since it is being cracked back to O2 more slowly than it is being
formed the drop in O2 partial pressure could become a concern, health
studies notwithstanding.

Where is fossil hydrogen found? What is being "cracked" back to o2?

Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ- Hide quoted text -

- Show quoted text -

He means fossil *hydrocarbons* (oil and gas)

 

[Jerry Avins]

On 12/13/2011 7:42 PM, Bret Cahill wrote:

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh...

Bret Cahill
There is too little information to see exactly how
they have extrapolated the data, but I have no
problems accepting the main thesis of the piece.

The main thesis of the propaganda is that the central-eastern
Tibetan Plateau represents the entire planet. You don't see any
problem with that?

Not really: Any claims to *global* warming should apply
to that area as well.

Actually part of the surface is _cooling_ as the rest is warming.

Sea level is the same way. In most places the sea level will rise but
in some it will drop.

Define "sea level"

Can you figure out why?

There's only one way: the land rises faster than the sea. Tide aside,
"water seeks its own level."

Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ

 

[Jerry Avins]

On 12/13/2011 9:17 PM, fatalist wrote:

On Dec 13, 3:31 pm, Jerry Avins<j...@ieee.org> wrote:
On 12/13/2011 2:35 PM, Bret Cahill wrote:

...

The sea level rise from burning fossil hydrogen ...

Where is fossil hydrogen found? What is being "cracked" back to o2?

...

He means fossil *hydrocarbons* (oil and gas)

How does one crack them back to O2?

I'd like to hear it from him.

Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ

 

[Bret Cahill]

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh...

LOL! Good catch. The writer of the propaganda seems to believe the
central-eastern Tibetan Plateau is the entire planet, therefore
all of the scientists on the planet are wrong. Amazing. Funny,
too.

Sure. The same argument works against claims the other
way, that are based on findings on the Greenland glacier
core samples: How would you justify a claim that local
findings are relevant on a global scale?

True but irrelevant here where we humor his claim that his tree data
correlate well with the medieval warm period and other documented
events.
And do contemplate what this means: *several* independent
data sets point in the same direction.

That's irrelevate in this thread as the tree ring data is assumed to
be accurate.

It's very relevant, as few if any data from outside lab
conditions can be taken at face value.

Then feel free to start a thread on it.

The OP here assumes the Chinese had good data.

If several
independent measurements point in the same direction,
that tends to be mutually supportive.

Here the problem is claiming a /1300 year frequency is signal when he
doesn't even have two periods of sampling time.  To be somewhat sure
it wasn't noise would require waiting another 1300 years.
Such a claim would be problematic if these data were
all there was.

It's problematic even if the temperature/time graphs are taken as
accurate.  That was the point of the OP.

The point is that you can not evaluate these data in
isolation;

That's not the point of _this_ thread. See the OP.

in that case they are just numbers. It is
only when they fit the big picture, already sketched
by other measurements, that they start making sense.

There is no way to know if the < 2 cycles of the 1/1300 year frequency
are signal or noise.  You have to wait a few thousand more years to be
sure.

So what?

We don't have several thousand years.

The FFT or periodogra or whatever is just
a mathematical method you can apply to the available
data.

And when it comes to determining if a frequency is signal or noise,
that method doesn't work for sample times < 2X the period.

This is what I have said throughout the whole thread:
The data themselves say nothing about what causes
them to look like they do. OK, the present data set
may or may not be subject to a 1300 year cycle.
That's not the point. The point is that the *present*
data, recorded over the past couple of decades, show
variation on a scale that is not at all unique for the
period and location under study.

There is no question climate scientists would like to low pass filter
but there just isn't any time.

Why would they?

Ask the Chinese who did the low pass filtering in _their_ study.

Just have a look at the data available.
As I said early on, the hard part is to let go of
mythlogy, vested interests and presuppositions.

That the deniers' problem.


Bret Cahill

 

[Tom P]

On 12/13/2011 07:18 PM, Orval Fairbairn wrote:

In article<9kpfq4FquqU1@mid.individual.net>,
Tom P<werotizy@freent.dd> wrote:

On 12/13/2011 06:10 AM, Orval Fairbairn wrote:
In article<9kngueFj7qU1@mid.individual.net>,
Tom P<werotizy@freent.dd> wrote:

On 12/13/2011 12:13 AM, Tom P wrote:
On 12/12/2011 05:49 PM, Bret Cahill wrote:
Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh..
.


Bret Cahill

Use of Fourier analysis.

Most would go with the two higher frequencies. The problem is
extrapolating off of the two cycles of the /1300 year frequency.


Bret Cahill





There is another aspect which I cannot understand from the article.
The researchers have presumably found by fourier analysis that there is
some proxy in the tree-ring data that displays the periodic signals
described- all well and good - but how do they determine the correlation
between the proxy and the instrumental temperature record? By Principal
Component Analysis? If so, why are their results any more reliable than
Briffa's?
Maybe someone with access to the paper can clarify?




Addendum - the paper is accessible, but it refers to yet another paper
for the source of the temperature data for the last 2485 years- based on
tree-ring analysis, lol. Let the paper chases begin!

BTW I'd like to echo Bret's suspicion as well that particularly when it
comes to low frequency signals - meaning cycle time comparable with
sample length - you can prove anything you want with fourier analysis.

.... including "hockey stick" tailoffs. If the data are not smooth, the
FFT will go unstable and show a tailoff at the end of the data stream
that does not represent realistic behavior. A common tailoff is the
"hockey stick" shap, popularized by Mann, et. al.

The end of the hockey stick since 1900 is instrumental data. No Fourier
analysis involved. The disputed part is the pre-instrumental part
derived by statistical analysis of proxies, in particular using the PCA
technique. AFAIK no Fourier analysis there either. Correct me if I'm
wrong.
PCA analysis relies on a time overlap between instrumental and proxy
data and attempts to determine which factors in the proxies correlate
with the instrumental data. It' not at all clear to me why anyone
should think that the extremely small changes in global temperatures
should have a detectable effect on tree-ring growth compared with the
major changes in annual growth due to rainfall or cloud cover, let alone
the implicit assumption that there is a linear relationship, without
which the PCA analysis is meaningless.

You need the Fourier analysis just to sort through the data scatter --
even with "instrumental" data, which, BTW, has not covered the Earth
until recent times.

What you have said so far makes little sense. You said:
<quote>
..... including "hockey stick" tailoffs. If the data are not smooth, the

FFT will go unstable and show a tailoff at the end of the data stream
that does not represent realistic behavior. A common tailoff is the
"hockey stick" shap, popularized by Mann, et. al.
/quote

But the post industrial data is NOT derived from FT analysis, and
moreover Mann's analysis is not based on FFT

So if you say that FFT "goes unstable", why are you now saying that you
need to use it?

 

[Bob Masta]

On Tue, 13 Dec 2011 13:59:45 -0800 (PST), Rune Allnor
<allnor@tele.ntnu.no> wrote:

On 13 Des, 22:06, AGWFacts <AGWFa...@ipcc.org> wrote:
On Mon, 12 Dec 2011 01:37:32 -0800 (PST), Rune Allnor

all...@tele.ntnu.no> wrote:
On Sun, 11 Dec 2011 20:52:48 -0800 (PST), Bret Cahill <BretCah...@peoplepc.com> wrote:

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh...

Bret Cahill
There is too little information to see exactly how
they have extrapolated the data, but I have no
problems accepting the main thesis of the piece.

The main thesis of the propaganda is that the central-eastern
Tibetan Plateau represents the entire planet. You don't see any
problem with that?

Not really: Any claims to *global* warming should apply
to that area as well. If there is one area that fails
to comply with the dominant thesis, there might be others.

This is a common misconception by the general public, and by
anyone else who hasn't been paying attention. *Global*
warming refers to average temperature over the whole planet,
not the average temperature of any given spot. Climate is
not a simple linear system.

Best regards,




Bob Masta

DAQARTA v6.02
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Science with your sound card!

 

[Tom P]

On 12/14/2011 05:49 AM, Bret Cahill wrote:

Assume the tree ring data is good.

http://joannenova.com.au/2011/12/chinese-2485-year-tree-ring-study-sh...

LOL! Good catch. The writer of the propaganda seems to believe the
central-eastern Tibetan Plateau is the entire planet, therefore
all of the scientists on the planet are wrong. Amazing. Funny,
too.

Sure. The same argument works against claims the other
way, that are based on findings on the Greenland glacier
core samples: How would you justify a claim that local
findings are relevant on a global scale?

True but irrelevant here where we humor his claim that his tree data
correlate well with the medieval warm period and other documented
events.
And do contemplate what this means: *several* independent
data sets point in the same direction.

That's irrelevate in this thread as the tree ring data is assumed to
be accurate.

It's very relevant, as few if any data from outside lab
conditions can be taken at face value.

Then feel free to start a thread on it.

The OP here assumes the Chinese had good data.

If several
independent measurements point in the same direction,
that tends to be mutually supportive.

Here the problem is claiming a /1300 year frequency is signal when he
doesn't even have two periods of sampling time. To be somewhat sure
it wasn't noise would require waiting another 1300 years.
Such a claim would be problematic if these data were
all there was.

It's problematic even if the temperature/time graphs are taken as
accurate. That was the point of the OP.

The point is that you can not evaluate these data in
isolation;

That's not the point of _this_ thread. See the OP.

in that case they are just numbers. It is
only when they fit the big picture, already sketched
by other measurements, that they start making sense.

There is no way to know if the< 2 cycles of the 1/1300 year frequency
are signal or noise. You have to wait a few thousand more years to be
sure.

So what?

We don't have several thousand years.

The FFT or periodogra or whatever is just
a mathematical method you can apply to the available
data.

And when it comes to determining if a frequency is signal or noise,
that method doesn't work for sample times< 2X the period.

This is what I have said throughout the whole thread:
The data themselves say nothing about what causes
them to look like they do. OK, the present data set
may or may not be subject to a 1300 year cycle.
That's not the point. The point is that the *present*
data, recorded over the past couple of decades, show
variation on a scale that is not at all unique for the
period and location under study.

There is no question climate scientists would like to low pass filter
but there just isn't any time.

Why would they?

Ask the Chinese who did the low pass filtering in _their_ study.

Just have a look at the data available.
As I said early on, the hard part is to let go of
mythlogy, vested interests and presuppositions.

That the deniers' problem.


Bret Cahill

I'd like to try and summarize some of the problems with this piece of
research.

1. The reliability of the tree-ring method.
Tree-rings do not deliver temperatures. Tree-rings tell us about
annual growth. By using tree-ring data as a proxy for temperatures we
are making assumptions.

2. The proxy data evaluation.

The paper does not describe the method used but refers to another
paper as source. However, if the same procedure is used as per Briffa,
then most likely the Principal Component Analysis is used. This in any
case requires an overlap between the proxy data and instrumental
temperature data. It is not clear over what time span reliable
instrumental temperature data has been available in the central-eastern
Tibetan Plateau. Figure 1 refers to "orange line, calibration series,
464 BC–834 AD; purple line, verification series, 835–1980 AD"
It's pretty obvious that there is no instrumental data covering the
whole of either of these time spans, so what did they use?

3. Reliability of conclusions from PCA analysis.

The idea of PCA is that we can set up a model that fits the proxy data
to the instrumental data. So long as the model is then used for
interpolating, this is unproblematic. However, the model can also be
used to hindcast, meaning estimate past temperatures, as well as
forecast into the future, which means that we are assuming that the
model is valid for time spans outside of the instrumental record.
Not long ago we had a discussion about PCA in connection with the
"hockey stick" graph. The upshot is that that according to the methods
used to discard or select the principal components it is possible to get
wildly different results. In addition, the Briffa pine-cone analysis
suffered a major debacle when revealed that the resulting forecasts for
years after the calibration timespan were wildly inaccurate. This calls
into question whether PCA analysis of tree-ring data really can deliver
any meaningful results in general, let alone provide a basis for Fourier
analysis.

4. The statistical significance of the conclusions from PCA analysis

The figure 1 displayed on the website shows standard deviations for
the temperature reconstruction. It is notable that with the exception of
a few points all of the values fall inside the 1 SD limits.
By comparison, CERN's non-announcement yesterday of the observation of
the Higgs Boson presented data with sigma 1.9 - not enough for a
conclusive announcement.

We now consider the Fourier analysis itself and the presentation of the
results.

5. Exaggerated power spectrum.

Figure 2 shows the power density vs. frequency a-1. Noticeable is that
the power density is extremely high for values corresponding to 500
years or more. However, this distribution may well be artifact, and is
quite typical for the power spectrum of any noisy data.
Conversely, the high frequency components are extremely weak.

6. Claimed frequency components.

As Bret points out, it is meaningless to identify frequency components
comparable to half the timespan of the data itself. Indeed, it is
questionable whether some of the higher frequencies are not simply
harmonics. Figure 3 shows such a picture, so it could be that we are
seeing harmonics of a sawtooth - but could it be we are also seeing
harmonics arising from the "clipping" of 2485 years of data?

7. Presentation of results.

The JoanneNova website chose to present Figure 5 as their favorite
graph, showing as it does a "forecast" of temperatures for the next 120
years(!).
Interesting is that the 1SD noise present in the original data has
totally vanished. Why no confidence limits?

 

[Jerry Avins]

On 12/14/2011 10:37 AM, Clay wrote:

...

I didn't know of the stork example. The example I like from astromomy
is in the Northern Hemisphere that total solar eclipses occur more
often on Wednesday than any other day of the week. What could possibly
be the linkage? This fact holds true when looking over 50, 100, 500,
1000 or more years time spans! The astromomer Jean Meus wrote a great
article on this. This is a great example that illustrates statistical
clustering and that correlation does not imply causality.

The seasonal variation of deaths by drowning the consumption of ice
cream and in the US correlate well. Does this imply causality? Probably
not. Is it to be expected? Almost certainly.

Jerry
--
Engineering is the art of making what you want from things you can get.
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