IEVref:845-11-20ID:
Language:enStatus: Obsolete
Term: meteorological optical range
Synonym1:
Synonym2:
Synonym3:
Symbol: ν
Definition: length of the path in the atmosphere that is required to attenuate by 95 % the luminous flux in a collimated beam from a light source at a colour temperature of 2700 K

NOTE 1 – The value of the attenuation has been chosen so that the term provides an approximate measure of the commonly used concept of (meteorological) visibility, which is the greatest distance at which a black object of suitable dimensions can be recognized by day against the horizon sky.

NOTE 2 – The meteorological optical range ν is related to the atmospheric transmissivity T, assumed to be uniform, by the formula

v= d 0 log0,05 logT MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgarqqtubsr4rNCHbGe aGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaq Fn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpe WZqaaeaaciWacmGadaGadeaabaGaaqaaaOqaaiaadAhacqGH9aqpca WGKbWaaSbaaSqaaiaaicdaaeqaaOWaaSaaaeaaciGGSbGaai4Baiaa cEgacaaMe8UaaGimaiaac6cacaaIWaGaaGynaaqaaiGacYgacaGGVb Gaai4zaiaadsfaaaaaaa@4425@ or T= 0,05 d 0 /v MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgarqqtubsr4rNCHbGe aGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaq Fn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpe WZqaaiqaciWacmGadaGadeaabaGaaqaaaOqaaiaadsfacqGH9aqpca aIWaGaaiOlaiaaicdacaaI1aWaaWbaaSqabeaadaWcgaqaaiaadsga daWgaaadbaGaaGimaaqabaaaleaacaWG2baaaaaaaaa@3D2F@

where d0 is the length specified in the definition of T.
These formulas are sometimes written

v= log0,05 logT MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgarqqtubsr4rNCHbGe aGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaq Fn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpe WZqaaeaaciWacmGadaGadeaabaGaaqaaaOqaaiaadAhacqGH9aqpda WcaaqaaiGacYgacaGGVbGaai4zaiaaysW7caaIWaGaaiOlaiaaicda caaI1aaabaGaciiBaiaac+gacaGGNbGaamivaaaaaaa@424C@ or T= 0,05 1/v MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgarqqtubsr4rNCHbGe aGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaq Fn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpe WZqaaiqaciWacmGadaGadeaabaGaaqaaaOqaaiaadsfacqGH9aqpca aIWaGaaiOlaiaaicdacaaI1aWaaWbaaSqabeaadaWcgaqaaiaaigda aeaacaWG2baaaaaaaaa@3C0F@

it being understood that v is the numerical value of the meteorological optical range ν measured with the "unit" d0 and T the numerical value of T.


Publication date:1987
Source
Replaces:
Internal notes:2017-06-02: Cleanup - Remove Attached Image 845-11-201en.gif

2017-06-02: Cleanup - Remove Attached Image 845-11-202en.gif
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VT remarks:
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