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Thursday, May 29, 2008

Monthly Long-Term Effects of ENSO on Global Temperature

As discussed in my previous post, “Annual and Long-Term Impacts of El Nino/Southern Oscillation (ENSO)”, the global temperature anomaly curve, the backbone of the AGW movement, is simply a running total of annual variations in global temperature. Applying this same trend calculation to scaled NINO3.4 anomaly data results in a curve that is extremely similar to that of produced by global temperature anomaly data. Refer to:

The same relationship applies to MONTHLY global temperature anomaly and NINO3.4 data. Refer to Figure 1. I won’t repeat the discussion on creating the graphs. I followed the same process I used for the annual data.

Figure 1

To determine the monthly scaling factor, I divided the 0.093 used in “Annual and Long-Term Impacts of El Nino/Southern Oscillation (ENSO)” by 12 to arrive at 0.00775.


Arno Arrak said...

What is missing in all this talk is a general understanding of what an El Nino actually is. You will find an explanation in my book "What Warming?" available on the Amazon site. Basically, we are talking of wave resonance on oceanic scale. An ENSO wave is reflected back and forth in the Pacific Ocean at a frequency determined by the size of the ocean itself. Its driving force is equatorial currents.These currents are blocked from entering the Indian Ocean by the Philippines and New Guinea so the water piles up at this turnaround point. Return flow is via the equatorial countercurrent. An Enso wave that reaches the equatorial shores of South America this way will then run ashore, spread out, release its heat, and we observe an El Nino event. But any wave that runs ashore must also fall beck. As it falls back and starts a return journey via the equatorial currents the water level drops in its wake as much as half a meter, cool water from below wells up, and a La Nina begins. You can think of it as analogous to someone blowing across the mouth of a tube to elicit a tone. The tone you get is a resonant tone of that tube. The equivalent of blowing across a tube is of course trade winds and the tone elicited is the resonant frequency of the ocean itself which is roughly one cycle every five years. This has been going on since the Panamanian Isthmus rose from the sea and is guaranteed to continue for the foreseeable future. There are some disturbing influences, such as typhoons that can create a storm surge. If by chance a storm surge should block the flow of the equatorial countercurrent when an ENSO wave is on the way its warm water will spread out in the middle of the ocean,release its heat and we get an El Nino Modoki. Or it could dump its water at the start of the countercurrent near New Guinea and send us a surprise super El Nino as happened in 1998. People have groped empirically to understand it and the Nino 3.4 gets close to the action. It sits astride the equatorial countercurrent where all El Ninos will have to pass through its territory.

Bob Tisdale said...

Arno Arrak: Thanks for the input. Please do not assume one post is the only discussion here on ENSO. If you were to use the search function in the upper left-hand crner you'd discover I've gone to great lengths to describe El Nino and La Nina events.


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