IEVref: 705-05-41 ID: Language: en Status: Standard Term: effective Earth-radius factor Synonym1: Synonym2: Synonym3: Symbol: k Definition: ratio of the effective radius of the Earth to the actual Earth radius NOTE 1 – This factor k is related to the vertical gradient dn/dh of the refractive index n and to the actual Earth radius a by the equation: $k=\frac{1}{1+a\frac{\text{d}n}{\text{d}h}}$ NOTE 2 – For an atmosphere having a standard refractivity gradient the value of k is taken as 4/3, corresponding to an effective radius of the Earth of approximately 8 500 km. Publication date: 1995-09 Source: Replaces: Internal notes: 2017-06-02: Cleanup - Remove Attached Image 705-05-41.gif CO remarks: TC/SC remarks: VT remarks: Domain1: Domain2: Domain3: Domain4: Domain5: