Time Annual Report - title and content

BIPM Annual Report on Time Activities 2020:
International Atomic Time (TAI) and Coordinated Universal Time (UTC)


Leap seconds [IERS Bulletin C]

Establishment of International Atomic Time and of Coordinated Universal Time

Geographical distribution of the laboratories that contribute to TAI and time transfer equipment

Table 1: Relative frequency offsets and step adjustments of UTC

Table 2: Relationship between TAI and UTC

Table 3: Acronyms and locations of the timing centres that maintain a UTC(k) and/or TA(k)

Table 4: Equipment and source of UTC(k) of the laboratories contributing to TAI in 2020

Table 5: Differences between the normalized frequencies of EAL and TAI

Table 6: Measurements of the duration of the TAI scale interval

Table 7: Mean fractional deviation of the TAI scale interval from that of TT

Independent local atomic time scales and Local representations of UTC

Relations of UTC and TAI with GPS time and GLONASS time

Clocks contributing to TAI in 2020

Table 8: Statistical data on the weights attributed to the clocks in 2020