Question:. Are there signs the Arctic polar vortex is weakening since, say 1950, or some other date we have reliable tracking data from? Would this be in concert with the other data we have on old and new sea ice, etc. Do we have data on soil temperatures?
At least in Alaska there is very little soil temperature data, and since soil temperatures vary greatly in short distance depending on ground cover. There are more permafrost temperature monitoring sites around the Arctic. These are reported on in the annual State of the Climate published by the American Meteorological Society as section in the Arctic Chapter (2022 edition here: https://ametsoc.net/sotc2022/SOTC2022_FullReport_final.pdf)
Question:. Are there signs the Arctic polar vortex is weakening since, say 1950, or some other date we have reliable tracking data from? Would this be in concert with the other data we have on old and new sea ice, etc. Do we have data on soil temperatures?
No. Neither the lower atmosphere (troposphere) polar vortex or high atmosphere (stratosphere) polar vortex show multi-decade trend, though of course there's short term (months to a few years) variability. There's a climate.gov explainer from 2021 on the high atmosphere polar vortex and addresses the lack of trend (https://www.climate.gov/news-features/understanding-climate/understanding-arctic-polar-vortex).
At least in Alaska there is very little soil temperature data, and since soil temperatures vary greatly in short distance depending on ground cover. There are more permafrost temperature monitoring sites around the Arctic. These are reported on in the annual State of the Climate published by the American Meteorological Society as section in the Arctic Chapter (2022 edition here: https://ametsoc.net/sotc2022/SOTC2022_FullReport_final.pdf)
Thanks very much for your reply and the links!