Last year there was a permanent flow of sea ice through the Nares Strait into Baffin. This year up to now the arch is still intact and the sea SW of it is already completely ice-free. When I turn to gerontocrat's postings in the area/extent thread I remember that Baffin Sea has much less ice than usual. Would a permanently open Nares Strait lead to higher Baffin Sea Ice or is the input of ice through the narrow Nares Strait negligible?
I found a great analysis study on Nares Strait below on nature.com. It is open access thankfully and confirms a lot of all the good analysis we have already produced in this thread. The author mentions that you can add +/- 2 days to the dates of formation, as definitions can vary. (On a personal note I'm glad to say it confirms my own record on southern arch formation in this thread and also Oren's record on arch breakdown).
I have attached two images from the article on arch formation and trends going back 4 decades. I think anyone who reads this thread will find it a "must" read ! (I have left the screen shots in large size in order to make it legible in this thread).
https://www.nature.com/articles/s41598-019-56780-6Back to your question Stephan. Inflow into Baffin Bay can be grouped into three main sources:
1) Inflow through Nares Strait (when it is open)
2) Inflow from the CAA. From the Lancaster and Jones Sound
3) New ice production in the North Water Polynya
The nature.com study says that there was a record volume went through the Nares Strait in 2007 when no arch formed (254 km
3).
So clearly an open Nares will export a lot of ice into Baffin Bay.
In 2009 there was only a northern ice arch and it resulted in a virtually ice-free Baffin Bay in July, which led to unprecedented summertime sea surface temperatures largely as a result of decreased albedo and 24-hour solar insolation.
When the arches form, the NOW polynya is a big source of new sea ice production for Baffin Bay inwinter and spring. But this will be thin ice. This study below estimates that this polynya is repsonsible for around 80% of sea ice passing through the northern gate of Baffin Bay. There is a lot of data in this study but inflow and outflow into Baffin is variable and complex.
https://www.the-cryosphere.net/13/1025/2019/tc-13-1025-2019.pdf