Antarctic Sea Ice Index (part 1)
A trip down under: a quick look at Antarctic sea ice using NOAA’s National Snow & Ice Data Center (NSIDC) Sea Ice Index (SII)
The National Snow and Ice Data Center offers some pretty tasty to the public through their online portal, which may be found here. Up to now I’ve been baking sea ice extent data for the volatile Arctic and so it makes sense to dip down below and have a look at what has been going on in the really big freezer.
If you manage to successfully negotiate NSIDC’s FTP server you’ll end up with a CSV file for Antarctic sea ice extent dating back to 26 October 1978, that contains 14,573 ‘daily’ records to 26 March 2023. The first thing we must note is that daily records were reliably kept from 1988 onward, with zero missing data after this point. Up to this watershed moment in NSIDC history missing records ran to as many as 29 per month, with an average of 15.0 missing records per month. That’s quite a lot of missing data and so the first kitchen chore of the morning was to replace missing values using a rather handy linear interpolation function within my stats package. This is not as dodgy as …