the Air Vent

Because the world needs another opinion

Posts Tagged ‘anomaly’

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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