the Air Vent

Because the world needs another opinion

Posts Tagged ‘temperature’

Half Year Cyclic Variaition in RSS,UAH and GISS Anomaly

Posted by Jeff Id on October 26, 2008

From my previous post we looked at the FFT of the three main temp metrics from which Tamino noticed a strong 1 year signal in the UAH weather. From Leif Svalgaard’s comments on my other post, the solar heating effect is compensated for on a monthly basis by some function. This creates a few problems, scientists need to know the response of the earth climate to solar forcing, the difference in albedo between the hemispheres, the phase angle lag created by the thermal mass of the climate system and any feedback mechanisms associated with the response to make an accurate correction.

The phase of the one year trend I found in my last post means that (not surprisingly) the AGW guys have underestimated the annual response to solar heating in all three anomaly metrics. In their defense, they may have simply estimated the lag incorrectly. e.g. The differrence between two slightly out of phase sine waves is a sine wave.

There is also a half year signal present in all three metrics. This kind of variation could be caused by seasonal effects or corrections between the hemispheres. Below are the three Fourier transforms I did of the three metrics.

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P Value Correlation, Who wants a backward hockeystick anyway?

Posted by Jeff Id on September 5, 2008

I found the following paragraph from the latest Mann paper interesting.

Reconstructions were performed based on both the ‘‘full’’ proxy
data network and on a ‘‘screened’’ network (Table S1) consisting of
only those proxies that pass a screening process for a local surfacetemperature
signal. The screening process requires a statistically
significant (P  0.10) correlation with local instrumental surfacetemperature
data during the calibration interval. Where the sign of
the correlation could a priori be specified (positive for tree-ring
data, ice-core oxygen isotopes, lake sediments, and historical documents,
and negative for coral oxygen-isotope records), a one-sided
significance criterion was used. Otherwise, a two-sided significance
criterion was used. Further details of the screening procedure are
provided in SI Text.

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The Death and Resurrection of the Hockey Stick – “The Jesus Paper”

Posted by Jeff Id on August 31, 2008

A great article on the history of the hockey stick temperature reconstruction and the great service that Steve McIntyre has done for climate science. This is a well written clear example of how climate change science is political rather than scientific.

Bishop Hill blog HERE

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AGW Part #5 – Limitations of Ice Core Data or The Smoking Gun #2

Posted by Jeff Id on August 25, 2008

From my previous post on ice core data “AGW Part #5 – Limitations of Ice Core Data or The Smoking Gun” we could see the regular variations in temperature over the last 10000 years regularly shifting up and down by as much as 1.5 degrees. We also saw in my post AGW part #4 – The History of Temperature that CO2 levels measured much lower than what we measure today and they typically lag behind temperature change.

I took the time to count the number of times our temperature has crossed the zero line in the last 5000 years. I counted 36 transitions across the zero line. I also counted 31 times where temperature shifted up or down by more than 1 degree C see below.

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AGW part #4 – The History of Temperature

Posted by Jeff Id on August 23, 2008

To determine how much the earth has warmed by man’s influence we need to have a good temperature and CO2 record from history. After all you can’t claim that we are destroying the planet if temperature varies up and down all the time. It turns out this is not particularly easy to do. The field of climate reconstruction is called paleoclimatology and its conclusions are as slippery and often contested as archeology.

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Anthropogenic Global Warming #3 – IPCC Global Warming Conclusions

Posted by Jeff Id on August 22, 2008

Ok, now I will show the latest “summary for policy making” document available on the internet and here.  This document is the current IPCC recommendations to the world as to how humankind should address global warming.

Because of the nature of the IPCC discussed in my first and second post, we already know they must have very strong wording in this document.  My article Anthropogenic Global Warming #2 discusses the review process as related to the full report here. Read the rest of this entry »

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