@prefix dct: . @prefix ns1: . @prefix ns2: . @prefix ns3: . @prefix rdfs: . @prefix skos: . a skos:Concept ; dct:created "2019-01-14" ; dct:modified "2019-01-14" ; ns2:hasProfile ; ns3:status ; rdfs:seeAlso ; skos:definition "Permafrost is soil or rock that has remained at a temperature at or below zero degrees Celsius throughout the seasonal cycle for two or more years. Thickness means the vertical extent of a layer."@en ; skos:exactMatch ; skos:prefLabel "permafrost layer thickness"@en ; ns1:hadPrimarySource .