<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:skos="http://www.w3.org/2004/02/skos/core#" xmlns:gcmd="https://gcmd.earthdata.nasa.gov/kms#" xmlns:dcterms="http://purl.org/dc/terms/" xml:base="https://gcmd.earthdata.nasa.gov/kms/concept/">
  <gcmd:gcmd>
    <gcmd:termsOfUse>https://cdn.earthdata.nasa.gov/conduit/upload/5182/KeywordsCommunityGuide_Baseline_v1_SIGNED_FINAL.pdf</gcmd:termsOfUse>
    <gcmd:keywordVersion>draft</gcmd:keywordVersion>
    <gcmd:schemeVersion>2025-07-25</gcmd:schemeVersion>
    <gcmd:viewer>https://gcmd.earthdata.nasa.gov/KeywordViewer/scheme/sciencekeywords/f4ec49af-b1c5-431c-968c-56890da96020</gcmd:viewer>
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  <skos:Concept rdf:about="f4ec49af-b1c5-431c-968c-56890da96020">
    <skos:broader rdf:resource="32d72476-ba7b-43fa-b054-84804278aa84"/>
    <skos:prefLabel xml:lang="en">REFRACTIVITY</skos:prefLabel>
    <skos:changeNote>Date=2025-08-28 User Id=system System Note=Added broader relation from REFRACTIVITY [f4ec49af-b1c5-431c-968c-56890da96020] to RADIO OCCULTATION PROFILES [32d72476-ba7b-43fa-b054-84804278aa84]</skos:changeNote>
    <gcmd:reference gcmd:text="https://journals.ametsoc.org/view/journals/atot/23/12/jtech1996_1.xml" xml:lang="en"/>
    <skos:definition xml:lang="en">Refractivity 𝑁 is the index of refraction 𝑛 less unity in parts per million, or 𝑁 = (𝑛 − 1) × 10^6. In GNSS radio occultation, it is retrieved using the Abel transform as applied to profiles of bending angle vs. impact parameter. Its dimension is unitless but typically designated as “N-units”, and its associated independent coordinate is altitude above the mean sea-level geoid.</skos:definition>
    <dcterms:modified>2025-08-28T19:44:55.021Z</dcterms:modified>
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