Arctic Sea Ice (part 3)

A bracing analysis of the poster child of globalist alarmism: what you always wanted to know about Arctic sea ice but were afraid to ask

Before I put down the error-laden Sea Ice Index (SII) and pickup up NSIDC’s canny Multisensor Analysed Sea Ice Extent (MASIE) project I’d like to do one more thing and that is to run spectral analysis over the daily means. Spectral analysis is a familiar tool to sound and other engineers who work with oscillating signals over time, and the simplest plain English explanation I can offer is that it is a mathematical technique that detects all the periodic frequencies that may be embedded within a complex signal. ‘Periodic’ simply means regular, like a tuning fork that gives off a pure tone at the international concert tuning pitch of A = 440Hz when struck. If we took a tuning fork into a loud and brash New Year party and recorded the mayhem on our smartphone then spectral analysis would reveal that pure tone hidden within all the chatter, clatter, thumping, popping, clapping, slurping and stomping.

So what ‘pure tone’ may we expect to discover within the daily series for mean Arctic sea ice extent? Well, the thing is, I have absolutely no idea! There may not be a periodic signal of any description that can be detected. Then again we know there is strong seasonality so we should see something that marks out the passage of 365 days. In frequency terms this would be 1 / 365 = 0.00274 and I’m placing all my betting money on seeing a single, massive spectral spike at this frequency in the periodogram.

Here it is:

My response to this is WERGH, I NEED A STRONG COFFEE!

I shall explain why.

Right over on the left we do indeed see a massive spike at a frequency of f=0.00274 that represents annual periodicity within the daily data series. Think of this as the annual ‘tone’ that sings out. To the right of this is a series of regularly spaced spikes that represent harmonics of that annual ‘tone’. Such supreme regularity in the harmonic series of a complex signal is usually what we see with a musical instrument, so what we have here is something quite extraordinarily beautiful and unexpected: we are looking at the sound of the sea ice, that sings out a note with clarity and purity just like a note blown on a flute or string plucked on a violin!

Above the fundamental of f=0.00274 musically-minded folk will recognised the octave (f=0.00548, f=0.01096, f=0.02192), the perfect fifth (f=0.00822, f=0.01644), major third (f=0.01370) and minor seventh (f=0.01918). Mix these in the right proportion and you get what I shall henceforth call the ‘ice tone’.

Convert these frequencies into days and you get periodicities marking 365 days (year), 182 days (half year), 122 days, 91 days (quarter year), 73 days, 61 days, 52 days and 46 days (eighth year). As ice analysts we should boggle at this because it means the ebb and flow of Arctic sea ice is closer to the dynamics of a violin string than it is to random chatter, clatter, thumping, popping, clapping, slurping and stomping of the polar climate.

Ditto For Monthly

I couldn’t resist running the analysis once more using the monthly mean series whilst the oven was still hot:

There’s a dirty great frequency component sitting at f=0.0833 which represents the fundamental frequency of the year (1 / 12 = 0.0833). Sitting to the right of this mighty fundamental tone is the half-year octave at f=0.1666, then the 4-month perfect fifth of f=0.2499, then a blip that is the quarter-year octave at f=0.3332, with evidence of higher frequency components beyond this.

How Is This Possible?

These most perfect, mathematical and highly musical relationships hidden with the Arctic sea ice extent time series data may seem quite incredible but we were given a very big musical clue back in the second slide of part 2. Here is that slide again:

That, dear readers, is a near-perfect sine wave; being the building block of all musical sound!

Kettle On!