Over the past 25 years, the Arctic Ocean has warmed significantly in conjunction with a rising global surface temperature (now breeching increases of +1.5-2.0C from a low +0.25C in the 1950’s) and a rapid decline overall in Arctic sea-ice. Changes to the tropospheric jet stream has led to cold extremes over Euroasia and North America in mid-Winter.
Sudden Stratospheric Warming (SSW) is a dramatic weakening of the stratospheric polar vortex; collapse of the Arctic Vortex wind system. In the 1990’s, SSW occurred infrequently and sporadically. Since 2000, it has occurred every year through the current year, 2018.
This is a qualitative and dramatic change to the Winter climate of North America and Central Europe. This has led to negative Arctic Oscillations so pronounced and deep that they have reached the Southern United States.
Previous to 2000, positive Arctic Oscillations were the norm with polar air reaching only ~55N. Over North America that meant that, above most populated cities and areas of Canada.
The situation is now changed. Even when in positive-mode, polar air reaches below the US-Canada border. When in negative-mode polar air may reach directly to the Gulf of Mexico in North America.
This has been successfully modeled using Community Atmospheric Model Version 5 (CAM5) and its earlier version of the CAM3. Various Sea-Ice models have been incorporated. The Los Alamos Lab ‘Community Ice CodE’ Version 4.0 (CICE4), now in the public domain for use with rights retained by the lab has been used. The Community Sea-Ice model, also has been used, as part of ‘The Community Earth System Model (CESM)’.
The results of all experimental modeling are statistically within 10% error bars when analyzing and forecasting the Arctic Vortex and its collapse with the sea-ice loss and warming in the B-K region playing a significant role.
Now, with global warming continuing unabated, a dramatic and qualitatively new change has again occurred. That of continual Arctic vortex collapse becoming a permanent feature of the Climate landscape.
What this means:
- A reversal of HIGH pressures and LOW pressures across the Northern Hemisphere in Winter.
- The negative Arctic Oscillation begins earlier; in September-October rather than November-December.
- The tropospheric jet stream drops across North America in November-December.
- HIGH and LOW pressure regions create novel weather patterns unseen before through the upper latitudes, and in unpredictable ways.
- The width of the drop over the North American land mass has been expanded.
- The Arctic Vortex Collapse does not abate, but continues and becomes continual in Winter, January-February.
- The net effect: freezing temperatures, ice cold wind storms, snow, and polar frigid temperatures from November-February over North America, from the Rocky Mountains to the Eastern Seaboard.
While other sources for the SSW have be evaluated, and no primary source has been identified before, in the last four (4) years it has been demonstrated one source is a likely candidate – the B-K Arctic Sea Ice at minimum and the concurrent extreme B-K Arctic Air and Sea temperatures.