tajmahal wrote:HockeyTx82 wrote:tajmahal wrote:
The article I linked covers these details.
A Canadian Warming is not a SSW.
Included some citations too.
A sudden stratospheric warming (SSW) is an event in which the polar stratospheric temperatures rise by several tens of kelvins over the course of a few days¹. The warming is preceded by a slowing then reversal of the westerly winds in the stratospheric polar vortex². SSWs occur about six times per decade in the northern hemisphere, and about once every 20-30 years in the southern hemisphere².
A Canadian warming is a special subtype of a SSW that occurs when a substantial warming area develops over Siberia and extends all the way over North America⁵. This is different from a typical SSW, which usually involves a displacement or a split of the polar vortex². A Canadian warming can have significant impacts on the surface weather, such as bringing colder temperatures to the eastern United States and Canada⁵.
The difference between a Canadian warming and a SSW is mainly in the location and structure of the warming area and the polar vortex. A Canadian warming is more localized over the North American continent, while a SSW can affect the entire polar region. A Canadian warming does not necessarily disrupt the polar vortex, while a SSW often does. A Canadian warming is also less frequent and less predictable than a SSW.
(1) New study questions explanation for last winter’s brutal U.S. cold snap.
https://news.ucar.edu/132831/new-study- ... -cold-snap.
(2) Sudden stratospheric warming - Wikipedia.
https://en.wikipedia.org/wiki/Sudden_st ... ic_warming.
(3) STRATOSPHERIC WARMING FORECAST - severe-weather.eu.
https://www.severe-weather.eu/global-we ... canada-fa/.
(4) Beast from the East 2? What 'sudden stratospheric warming' involves and ....
https://theconversation.com/beast-from- ... her-152876.
(5) Impact of Climate Change on Stratospheric Sudden Warmings as ... - AMETSOC.
https://journals.ametsoc.org/view/journ ... 3069.1.xml.
Your debate is with the author, who is a worldwide–respected scientist about the stratospheric polar vortex and who regularly publishes in our most prestigious, peer reviewed science journals, like "Nature."
Dr. Judah Cohen is a leading expert on the Arctic Oscillation (AO) and the Polar Vortex (PV), which are atmospheric phenomena that influence the weather patterns in the Northern Hemisphere. He has published many papers and blogs on the topic, and he also provides seasonal forecasts and subseasonal predictions based on his research¹⁴.
Some of his main findings are:
- The AO and the PV are closely related, and they can be either in a positive or a negative phase. A positive AO/PV means that the polar jet stream is strong and confined to high latitudes, while a negative AO/PV means that the polar jet stream is weak and wavy, allowing cold air to spill southward and warm air to move northward¹.
- The snow cover extent in Eurasia during October and November can affect the strength and variability of the AO/PV in the following winter. More snow cover tends to favor a negative AO/PV, while less snow cover tends to favor a positive AO/PV¹.
- The stratospheric PV can undergo sudden and dramatic disruptions, called sudden stratospheric warmings (SSWs), which can propagate downward to the troposphere and affect the surface weather for weeks to months. SSWs are more likely to occur when the tropospheric PV is already weak or negative¹.
- The Arctic sea ice extent and the Arctic amplification (the enhanced warming of the Arctic compared to the rest of the globe) can also influence the AO/PV, but their effects are more complex and uncertain. Some studies suggest that sea ice loss and Arctic amplification can weaken the polar jet stream and favor a negative AO/PV, while others suggest that they can strengthen the polar jet stream and favor a positive AO/PV¹.
Dr. Cohen's research is widely cited and respected in the scientific community, but it is not without challenges and criticisms. Some of the counters to his research are:
- The relationship between snow cover and AO/PV is not robust and consistent across different datasets and methods. Some studies find no significant correlation or even a positive correlation between snow cover and AO/PV, contrary to Dr. Cohen's hypothesis²³.
- The mechanisms and pathways by which snow cover, sea ice, and Arctic amplification affect the AO/PV are not fully understood and modeled. There may be other factors and feedbacks that modulate or override their influences, such as the El Niño-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Quasi-Biennial Oscillation (QBO), and the solar cycle²³.
- The predictability and skill of the AO/PV and its impacts on surface weather are limited by the chaotic nature of the atmosphere and the uncertainties in the initial conditions and the model physics. The AO/PV forecasts can vary widely among different models and methods, and they can also change significantly from one update to another²³.
Dr. Cohen acknowledges the limitations and uncertainties of his research, and he welcomes constructive feedback and debate from his peers and the public. He continues to refine and improve his methods and models, and he also collaborates with other researchers to advance the science and understanding of the AO/PV and its implications for weather and climate.
(1) Arctic Oscillation and Polar Vortex Analysis and Forecasts - AER.
https://www.aer.com/science-research/cl ... cillation/.
(2) Judah Cohen - Aspen Global Change Institute.
https://www.agci.org/people/0034x00001A ... udah-cohen.
(3) Arctic Oscillation and Polar Vortex Analysis and Forecasts - AER.
https://www.aer.com/siteassets/ao-archi ... pdated.pdf.
(4) Arctic Oscillation and Polar Vortex Analysis and Forecasts - AER.
https://www.aer.com/siteassets/ao-archi ... -01-24.pdf.
(5) Arctic Oscillation and Polar Vortex Analysis and Forecasts.
https://www.aer.com/siteassets/ao-archi ... -11-06.pdf.