Modelling Arctic Sea Ice (part 4)

Using a supplemented dataset incorporating NSDIC’s Sea Ice Index (SII) to explore the relationship with sea ice extent, sea surface & land surface temperate anomalies

So far in this series, which began back on 10^th February, we’ve looked at cross-correlation function plots of:

• Sea surface temperature (SST) with land surface temperature (LST)

• Sea surface temperature with sea ice extent (SIE)

• Land surface temperature with sea ice extent

• Atmospheric CO2 with sea ice extent

• Sunspot Number (SSN) with land surface temperature

Sunspot Number (SSN) with land surface temperature over the period 1900 - 2022 is arguably the most surprising result so far, so here is that slide again by way of refresher:

Positive-going bars peeking beyond the 95% upper confidence limit indicate a statistically significant positive correlation (SSN and LSA rising and falling together); negative-going bars peeking beyond the 95% lower confidence limit indicate a statistically significant negative correlation (SSN and LSA going in opposite directions). Bars at positive lags mean LSA is responding to SSN (i.e. a potentially causal relationship); bars at negative lags indicate LSA has changed before the SSN changes (i.e. not causal).

Hence we’ve got evidence of a possible causal relationship between mean daily sunspot number and land surface temperature anomaly (positive bars at positive lags), but we’ve also got evidence suggesting this relationship is not causal (positive bars at negative lags). Then there are those negative correlations at positive and negative lags that cloud the issue (see what I did there?).

What smacks us between the eyes is that regular wave-like pattern of up then down. If we measure the positive peak-to-positive peak distance we are talking 11 years plus or minus a couple of years. If we now measure the negative peak-to-negative peak distance we are still talking 11 years plus or minus a couple of years. We’re talking solar!

The Whole Hog

We now need to complete the picture by looking at SSN with SST and SSN with SIE, and whilst I’ve got my crayons out we can go the whole hog and look at SSN with CO2. Here are those slides: