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Area Lighting / Lighting technology and daylighting

IEV ref 845-29-109

Symbol
m

en
relative optical air mass
quotient of the optical thickness of the atmosphere at angle ε to the vertical, δ(ε), and the vertical optical thickness, δ(0°), of the atmosphere

m= δ(ε) δ(0°) MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aad2gacqGH9aqpdaWcaaqaaiabes7aKjaacIcacqaH1oqzcaGGPaaa baGaeqiTdqMaaiikaKaaajaaicdakiabgclaWkaacMcaaaaaaa@43BE@

Note 1 to entry: See also "optical thickness".

Note 2 to entry: Several equations are available to express this concept. Usually the Kasten–Young formula is used:

m= 1 [ sin  γ s  + 0,505 72 ( γ s  + 6,079 95) 1,6364 ] MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aad2gacqGH9aqpdaWcaaqaaiaaigdaaeaadaWadaqaaiaabohacaqG PbGaaeOBaiaabccacqaHZoWzdaWgaaWcbaGaae4CaaqabaGccaGGGc Gaey4kaSIaaiiOaKaaajaaicdacaGGSaGaaeynaiaaicdacaqG1aGa aeiiaiaabEdacaqGYaGccaGGOaGaeq4SdC2aaSbaaSqaaiaabohaae qaaOGaaiiOaiabgUcaRiaacckajaaqcaqG2aGaaiilaiaaicdacaqG 3aGaaeyoaiaabccacaqG5aGaaeynaOGaaiykamaaCaaaleqabaGaey OeI0IaaeymaiaacYcacaqG2aGaae4maiaabAdacaaMc8Uaaeinaaaa aOGaay5waiaaw2faaaaaaaa@5F86@

where γs (= 90° − ε) is solar altitude (complementary angle of zenith angle, ε) in degree.

Note 3 to entry: When the curvature of the atmosphere and atmospheric refraction are neglected:

m= 1 cosε MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aad2gacqGH9aqpdaWcaaqaaiaaigdaaeaajaaqcaqGJbGaae4Baiaa bohakiabew7aLbaaaaa@3EA5@ .

Note 4 to entry: The relative optical air mass has unit one.

Note 5 to entry: This entry was numbered 845-09-88 in IEC 60050-845:1987.


fr
masse d'air optique relative, f
quotient de l'épaisseur optique de l'atmosphère à l'angle ε par rapport à la verticale, δ(ε), par l'épaisseur optique verticale, δ(0°), de l'atmosphère

m= δ(ε) δ(0°) MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aad2gacqGH9aqpdaWcaaqaaiabes7aKjaacIcacqaH1oqzcaGGPaaa baGaeqiTdqMaaiikaKaaajaaicdakiabgclaWkaacMcaaaaaaa@43BE@

Note 1 à l'article: Voir aussi "épaisseur optique".

Note 2 à l'article: Plusieurs équations permettent d'exprimer ce concept. Généralement, la formule de Kasten–Young est utilisée:

m= 1 [ sin  γ s  + 0,505 72 ( γ s  + 6,079 95) 1,6364 ] MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aad2gacqGH9aqpdaWcaaqaaiaaigdaaeaadaWadaqaaiaabohacaqG PbGaaeOBaiaabccacqaHZoWzdaWgaaWcbaGaae4CaaqabaGccaGGGc Gaey4kaSIaaiiOaKaaajaaicdacaGGSaGaaeynaiaaicdacaqG1aGa aeiiaiaabEdacaqGYaGccaGGOaGaeq4SdC2aaSbaaSqaaiaabohaae qaaOGaaiiOaiabgUcaRiaacckajaaqcaqG2aGaaiilaiaaicdacaqG 3aGaaeyoaiaabccacaqG5aGaaeynaOGaaiykamaaCaaaleqabaGaey OeI0IaaeymaiaacYcacaqG2aGaae4maiaabAdacaaMc8Uaaeinaaaa aOGaay5waiaaw2faaaaaaaa@5F86@

γs (= 90° − ε) est l'altitude solaire (angle complémentaire de l'angle zénithal, ε) en degré.

Note 3 à l'article: Lorsque la courbure de l'atmosphère et la réfraction atmosphérique sont négligées:

m= 1 cosε MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aad2gacqGH9aqpdaWcaaqaaiaaigdaaeaajaaqcaqGJbGaae4Baiaa bohakiabew7aLbaaaaa@3EA5@ .

Note 4 à l'article: L'unité de la masse d'air optique relative est un.

Note 5 à l'article: Cet article était numéroté 845-09-88 dans l'IEC 60050-845:1987.


ar
كتلة الهواء البصرية النسبية

de
relative optische Luftmasse, f

it
massa ottica relativa dell'aria

ko
상대 광 대기노정

ja
光学的空気量
大気路程

pl
gęstość optyczna atmosfery względna, f

pt
massa de ar óptica relativa

zh
相对大气光学质量

Publication date: 2020-12
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