@prefix dct: . @prefix ns1: . @prefix ns2: . @prefix rdfs: . @prefix skos: . a skos:Concept ; ns2:creator "European Space Agency", "Spot Image S.A." ; ns2:date "2010-03-23" ; ns2:source ; dct:created "2010-03-23" ; dct:modified "2012-02-14" ; ns1:hasProfile ; rdfs:seeAlso , , ; skos:altLabel "TAI" ; skos:definition "TAI is the atomic time scale of BIPM; its unit interval is exactly one SI second at sea level. The origin of TAI is such that UT1-TAI ~ 0 on January 1st 1958, but the beginning of the TAI measurements goes back july 1955. The instability of TAI is about 6 orders of magnitude smaller than that of UT1. Quarterly values of UT1-TAI since 1962 and predicted ones are given."@en ; skos:exactMatch , , "urn:ogc:def:trs:BIPM::TAI" ; skos:prefLabel "TAI"@en .