> The is no such thing as TAI. TAI is what you get if you start with UTC and then subtract the number of leap seconds you care about. TAI is not maintained as s

> The is no such thing as TAI. TAI is what you get if you start with UTC and then subtract the number of leap seconds you care about. TAI is not maintained as some sort of separate standard quantity. There is, though? You can easily look at the BIPM's reports [0] to get the gist of how they do it. Some of the contributing atomic clocks are aligned to UTC, and others are aligned to TAI (according to the preferences of their different operators), but the BIPM averages all the contributing measurements into a TAI clock, then derives UTC from that by adding in the leap seconds. [0] https://webtai.bipm.org/ftp/pub/tai/annual-reports/bipm-annual-report/annual_report_2020.pdf https://webtai.bipm.org/ftp/pub/tai/annual-reports/bipm-annu...