The Biannual Arctic Oscillation and it's association with Influenza Outbreaks since 1950.

The negative mode of the Arctic Oscillation seems to be associated with flu outbreaks. The reason speculated is a -AO allows the polar jet to slow down and allow cold air to flow meridionally south into the mid-latitudes. This cold air effects the population and the Influenza Virus in a way that's favorable for infection.

1. People are more likely to stay in buildings and domisciles, spreading the virus between each other.

2. Your body needs to use energy to heat your body depleting energy away from your immune system.

3. The flu virus is very hardy in the winter cold, it's external shell becomes a barrier to allow it to live in the cold better. Therefore, it stays around in the cold to infect the population.

The literature also equates Influenza with PDO and ENSO modes, but I figured I'd try the AO which fit rather well. The 4 main Flu Outbreaks since 1950 are denoted by the more negative biannual values of the Arctic Oscillation where the most negative value ranks 1st and the most positive value ranks last. The four Influenza Outbreaks rank one, two, four, and sixteen since 1950. It's rather telling that the clustering toward the top of the rank in mainly denoted by Hong Kong, H1N1, & Asian Flu (1,2, and 4 ranked respectively). As for the 16th ranked Russian Flu (which happened to be a late 70's winter), I speculate it may have been dictated by Scandinavian or East Asian/West Russian blocking mechanism versus the Arctic Oscillation, maybe even the TNH teleconnection.

Here is the graphic: