Over the past couple of years, we all have heard the whole “snow cover brings colder air” or “we need more sea ice” A little research into the matter and I discovered a great deal on the differences between them. Most of us know that in September is typically when Ice has reached its yearly minimal and begins to build. We all have seen post on twitter comparing sea ice rate of loss or gain to previous years in September. This is meaningless, more importantly it is the total ice loss through the melting season that seasonal questions can begin having answers (Poles Apart, 2012).
Snow cover of course, is easier to predict and know the outcome. Just follow the winds and the cold temps will follow. However, sea ice has a huge impact on our weather in the south.
It has long been hypothesized that sea ice plays a major role in determining climates across the northern hemisphere. According to Koenigk, Caian, & Nikulin, G.
et al. (2016 pp 317-337) “sea ice variations in eight different Arctic regions on the winter climate conditions in mid and high northern latitudes has been analyzed using ERA-interim reanalysis and satellite data. We used detrended data and performed both correlation and composites analyses to assess the seasonal predictability connected to the different ice areas”. They go on and say, “starting from November, we find a winter SLP response, which resembles the NAO or AO pattern for the first three areas (negative NAO/AO after low ice); high ice in Laptev/East Siberian Seas is followed by reduced SLP over large parts of Europe, northern Canada and eastern Asia. Related to this, the impact of November sea ice on blocking over the Euro-Atlantic region is substantially increased compared to September ice. Particularly ice variations along the Siberian coast are of importance for the blocking. The winter SLP response to September ice area variations does not show strong similarity to the NAO-pattern”.
After studying the research paper, I found that
November sea ice in areas that cover from Greenland and Scandinavian seas play a major role in signaling the sign of NAO in the previous winter. While anomalies in the Labrador Sea suggest a more NAO-pattern. Some have speculated that there is a link between ice anomalies and the stratosphere.
We cannot take a comparison from September to November as being any kind of sign for winter. However, November sea ice has data to back up its clam on determining the blocking and teleconnections across the northern hemisphere.
In case you want to read more here are my sources:
Koenigk, T., Caian, M., Nikulin, G.
et al. Regional Arctic sea ice variations as predictor for winter climate conditions.
Clim Dyn 46, 317–337 (2016).
https://doi.org/10.1007/s00382-015-2586-1
Poles apart: A record-breaking summer and winter (Beitler, 2012).
National Snow and Ice Data Center.