86
THERMODYNAMIC METEOROLOGY
COMPARISON OF Ri„ WITH R\
Height z
116
500
1000
1500
2000
2500
3000
4000
5000
Rio
287.28
286.87
285.34
283.14
280.50
278.21
275.59
272.06
R'i o
282.91
287.35
285.65
281.68
277.95
275.46
274.09
268.89
R' 10 is generally smaller than R 10 in these observations.
Pi -Po .
The term
Pio
is taken directly from Table 17, and
Wi — Wo is easily computed. Then Ui—U 0 follows from (335).
In computing the radiation, K i0 = ^~Z. V °> the values of
v are the reciprocal of the density p in Table 14. Had p been
computed by formula (175), which takes R constant, instead of
by (176), with R variable, it is seen at once how erroneous
would have been the derived radiations, because the values of
K w depend upon the small differences (z>i — v 0 ) in succession.
These radiations are mean values for the strata concerned. It
is important to study the relation of the radiation to the tem
perature, and to compare the exponents of formula (340) with
the exponent of a full radiation in the Stephan Law, which is 4.
This subject is complex in the earth’s atmosphere as will be in
dicated. The problem is as follows: The values of K in re
lation to T by (340) are in the form of ratios, whereas in the
Stephan Law (344) they stand related through a coefficient.
If the constituent of the ratio is in the form (343), it is quite
certain that the coefficients (C . c) are not equal, nor are the expo
nents (.A . a). We proceed to develop the relations between
C and c, A and a. The equation (343) gives three terms, K w ,
A, T 10 , from which to compute C, and it is necessary to indicate
what are the relative values of log C and A. With the data of
Table 19 in the first section of Table 20, compute A log T 10
and subtract this from log Ki 0 to obtain log C. The negative
sign before the logarithm affects only the characteristic. Thus,
logarithm — 11.944 gives the number 8.79 X 10 _u . In this