Tables 686 and 687 cr 5 



TABLE 686. — Transmission of Solar Radiation by Earth's Atmosphere 



(Kimball, Monthly Weath. Rev., 56, 393, 1928; 58, 43, 1930.) 



Upper curves give transmission (sea-level) by the general scattering by dust-free moist 

 air summed over all wave lengths (w = precipitable water in beam) ; lower curves, the 

 added fractional depletion in the selectively absorbing water-vapor bands. No allowance 

 is indicated for dust. (See also Table 767.) 



Air Mass. m. (Pressure -760 cm) 



JO 20 



16, 



14 



16 



cum 



TABLE 687. — Ultra-Violet Solar Radiation at Earth's Surface 



Average ultra-violet solar radiation of wave lengths <3i3 m/t on the clearest days in 

 Washington during 1930-31. Data in g-cal./cm7min. y io 5 (Coblentz, Stair, Bur. Stand- 

 ards Journ. Research, 6, 971, 1931). 



May June July Aug. Sept. Oct. 



35 41 42 41 33 16 



58 63 63 59 50 35 



70 76 76 71 61 48 



76 82 81 76 66 53 



0.0008 cal./cmVmin. = 56 microwatts. Data are also given for greater elevations. At 

 high elevations the spectrum quality of the u.-v. region is richer in the shorter wave lengths 

 than at sea-level ; but owing to sky-scattering, the total amount of u.-v. light less than 

 313 mfi at sea-level, on the clearest days, is almost as large as at high elevations. 



Smithsonian Tables 



