Table 68 (continued) 281 



NAGA STANDARD ATMOSPHERE, TENTATIVE PROPERTIES OF THE 

 UPPER ATMOSPHERE 



composition of the upper atmosphere were recommended by the Subcommittee and have 

 been adopted for the purposes of computing the values in these tables : 



(1) For daytime, the dissociation of oxygen is such as to produce a constant volume 



gradient 3 from all-molecular oxygen at 80 kilometers to all-atomic oxygen at 

 100 kilometers. Except for oxygen dissociation the composition is the same as 

 that at sea level. 



(2) For night time, the dissociation of oxygen such as to produce a constant volume 



gradient 3 from all-molecular oxygen at 105 kilometers to all-atomic oxygen at 

 120 kilometers. Except for oxygen dissociation the composition is the same as 

 that at sea level. 



(3) At altitudes below the regions of oxygen dissociation the composition is the same 



as that at sea level. 



(4) At altitudes above the regions in which both molecular and atomic oxygen exist, 



as stipulated in (1) and (2), and up to at least 120 kilometers, the composition is 

 the same as that at sea level, except for oxygen which is in the atomic rather 

 than molecular form. 



List of Symbols. — 



p = mass per unit volume, 

 p = pressure, 



T = temperature °A. (=273 + °C), 

 M = molecular weight, 

 h = height, 



g = acceleration of gravity, 

 v = volume fraction of molecular oxygen in normal dry air. 



The following subscripts are used to refer to the indicated conditions : 



o = sea level, 

 i = lower level, 



m = base of the region of oxygen dissociation, 



o = top of the region of oxygen dissociation where oxygen is all atomic, 

 a = base of region with constant temperature and constant composition, 

 b = base of region with constant temperature gradient and constant composition, 

 o = base of region with constant temperature and constant volume gradient of 



dissociation, 

 d = base of region with constant temperature gradient and constant volume 



gradient of dissociation. 



Basic constants. — In addition to the constants for the lower atmosphere given in 

 Table 63, the following sea-level values of the various quantities have been adopted: 



Coefficient of viscosity no = 17835 X 10" 8 poise 



Kinematic viscosity v a = -^ = 14.553 X 10 -8 m. 2 sec. -1 



Po 



Speed of sound ao = 340.22 m. sec." 1 



Mean free path of nitrogen molecules X n = 7.38 X 10" 8 m. 



Mean free path of oxygen molecules Xo = 7.36 X 10" 8 m. 



Mean free parth of air molecules X a i r = 7.37 X 10~ 8 m 



Average molecular weight Mo = 28.966 



Ratio of specific heats 70 = 1.4 



Volume fraction of oxygen in normal dry air v<> = 0.2095 



Basic equations. — In addition to the specifications for temperature and composition 

 already listed, certain other assumptions are made and serve as the basis for deriving 



8 "Constant volume gradient" signifies linear variation with height of the existing volume of molecular 

 oxygen per unit initial volume of normal dry air. 



(continued) 



SMITHSONIAN METEOROLOGICAL TABLES 



