El Nino Southern Oscillation Index
In a recent article by Kevin Trenberth amongst his silly comments he mentioned El Nino and Pacific Decadal Variability as one of many “the dog ate my warming” type excuses to deny the scientific fact of the pause.
In my comment to his diabtribe I suggested that PDO is very likely being just a manifestation of natural variation and this is a fuller explanation.
LC circuit
For the academics looking at the earth’s climate it must be very confusing because they have a lot of strange phenomenon which appear to be “something” but whilst appearing to be cyclic, they are otherwise quite random in size. Such well known phenomenon are the El Nino, Pacific Decadal Oscillation, North Atlantic oscillation, etc.
I would now like to suggest how these phenomenon are likely to be just a manifestation of natural variation.
Above right is an electrical tuned circuit. This is the fundamental circuit on which radio was built. The inductor (L) give inertia to the system like a weight and the capacitor acts rather like a spring. In addition any real circuit has internal resistance. The result is that the tuned circuit is resonant and if a signal is applied across it close to the resonant freqency, the circuit will tend to have a current flowing around the loop between the inductor and capacitor which in a radio effectively amplifies the wanted frequencies and removes unwanted frequencies.
Likewise, when I was last on a ferry, there was a similar resonance. Someone in the ship was a deck or some other springy area whose weight and springiness caused it to resonate with the engines so as to slightly amplify the noise at one frequency. So, such resonance is commonplace.
Showing effect of narrow pass filter on pink noise is to produce apparent cyclic signal
But how does this relate to El Nino, PDO, etc? What is noticeable about all these supposed phenomenon is that they are massed CIRCULATIONS of currents. In other words, they behave very much like the tuned LC circuit above in that they tend to have a natural resonant frequency. As such, when exposed to random noise such as the pink noise shown above left, they tend to amplify frequency components close to their resonant frequency and remove those outside leaving an apparent cycle as show above right. This is a very likely reason why El Nino appears to be an oscillation:
Pacific Decadal Oscillation index
El Nino Southern Oscillation Index (see top for bigger)
So, rather than being a “cycle”, their random size appears to indicate that they are instead “resonant response” to wide frequency natural variation.
So, these are not really phenomenon at all. Instead they are just parts of the earth’s system that tend to respond in tune with a whole range of changes we sceptic call “natural variation”.Yes, they appear cyclic, as if there is something actively driving a cycle, but in reality they are very likely to be passive resonance of the earth’s systems and the way they fluctuate wildly in size from year to year is very characteristic of a resonant circuit responding to wideband noise.
