@prefix dct: . @prefix ns1: . @prefix ns2: . @prefix rdfs: . @prefix skos: . a skos:Concept ; ns1:creator "European Space Agency", "Spot Image S.A." ; ns1:date "2010-03-23" ; ns1:source ; dct:created "2010-03-23" ; dct:modified "2012-02-14" ; ns2:hasProfile ; rdfs:seeAlso , , ; skos:altLabel "UT1" ; skos:definition "UT1 can be regarded as a time determined purely by the rotation of the Earth. It is computed by correcting UT0 for the effect of polar motion on the longitude of the observing site. UT1 is related to the Greenwich mean sidereal time (GMST) by a conventional relationship; It is often expressed as the difference UT1-TAI or UT1-UTC."@en ; skos:exactMatch , , "urn:ogc:def:trs:IERS::UT1" ; skos:prefLabel "UT1"@en .