Jennifer Francis, Rutgers University – assesses the broad topic of the Arctic Sea Ice Decline and explains seasonal impacts.
Observations, especially since the 1950′s, explain how the “Arctic Amplification” leads to rapid sea ice changes during the summer month. Much more ridging in North America during the winter. And this affects weather patterns, because a higher amplitude Jet Stream builds. More ridging through the Northern Hemisphere, stucky-persistence weather patterns emerge in Mid Latitudes. A record negative Northern Atlantic Oscillation (NAO) – drives sea ice into the Atlantic – rapidly out of the arctic. Almost all old (+5 years) arctic ice gone, within years.
Arctic Amplification and anthropogenic climate change – high latitudes warming more than mid-latitudes, especially in fall and winter, but also during summer over land -> poleward thickness gradient weackening. This creates weaker upper-level, zonal mean flow, reduced phase speed. Peaks of upper-level ridges elongate northward, wave amplitude increases.
And Rossby waves (North to south winds) progress more slowly. Weather conditions become more persistent. Increased probability of extremes: cold spells, heat waves, flooding, prolonged snowfall, and drought.