https://cdn.earthdata.nasa.gov/conduit/upload/5182/KeywordsCommunityGuide_Baseline_v1_SIGNED_FINAL.pdf 23.7 2026-04-15T10:53:30.610Z https://gcmd.earthdata.nasa.gov/KeywordViewer/scheme/sciencekeywords/1f4cdbc4-0f65-4384-83c9-9422c280717d PERMAFROST Date=2021-08-27 User Id=tstevens Entity=Definition Operation=UPDATE Field=reference System Note=update Definition New Value=American Meteorological Society Glossary of Meteorology Date=2024-09-26 User Id=tstevens Entity=WeightedRelation Operation=INSERT System Note=insert WeightedRelation New Value=id: null related concept uuid: b6723314-3db7-4bdd-85ee-0b8507e6ae1b relationship type: null relationship value: null generated by: null Date=2021-08-27 User Id=tstevens Entity=Definition Operation=UPDATE Field=text System Note=update Definition Old Value=Pertaining to the extent, depth, and other characteristics of frozen subsoil located in arctic/subarctic areas New Value=A layer of soil or bedrock at a variable depth beneath the surface of the earth in which the temperature has been below freezing continuously from a few to several thousands of years. A layer of soil or bedrock at a variable depth beneath the surface of the earth in which the temperature has been below freezing continuously from a few to several thousands of years. 2024-09-26 15:07:08.0