Optical clocks of the National Institute of Information and Communications Technology (NICT, Japan) and LNE-SYRTE (Systemes de Reference Temps-Espace, Observatoire de Paris, Universite PSL, CNRS, Sorbonne Universite, France) evaluated the latest "one second" tick of the International Atomic Time (TAI) and provided these data to the Bureau International des Poids et Mesures (BIPM) to be referred for adjusting the tick rate of TAI. Primary frequency standards based on the cesium microwave clock transition or a secondary standard based on a rubidium microwave transition have long played a role to calibrate the scale interval of TAI.
