re: #40 albusteve

this is not a matter of upper atmospheric wave patterns though. It is related to the fact that the thermohaline circulation is driven in part by sea ice formation at the poles. Salty, dense water is left behind when ice forms. It is denser than fresh water, and therefore sinks, driving a global scale circulation whose return flow is poleward. This poleward flow transports energy northward from the tropics.