208 RADIO WAVE PROPAGATION EXPERIMENTS 
Ma (dry term), VM, (wet term), and M, (curvature 
term) separately. 
Dry Term. Since equation (4) contains the pressure 
p, Which is not usually measured as a function of 
height, it is necessary to eliminate direct considera- 
tion of p. For this purpose a simplification of the 
calculating height as a function of pressure is suffi- 
cient. This simplification neglects very small pressure 
effects caused by humidity variations and the change 
of the acceleration of gravity with height. This prob- 
lem is discussed more fully in the section on pressure 
versus height, below. The pressure may then be written 
elaborate formula used in the Smithsonian tables for p = pe, (8) 
Taste 3A. H fort from —30 C (—22 F) to —20 C (—4 F); h to 2,000 m (6,562 ft). 
po = 1,000 mb at sea level 
\ie > 
—26 —25 —24 
Va 
7 h (ft) 
dl 0 325.1 323.8 322.4 321.1 319.8 318.5 317.3 316.0 314.7 313.5 312.3 0.0 
10 324.6 323.3 322.0 320.7 319.4 318.1 316.9 315.6 314.3 313.1 311.9 32.8 
20 324.2 322.9 321.5 320.3 319.0 317.7 316.5 315.2 313.9 312.7 311.5 65.6 
30 323.7 322.4 321.1 319.8 318.5 317.2 316.0 314.7 313.5 312.2 311.0 98.4 
40 323.3 322.0 320.6 319.4 318.1 316.8 315.6 314.3 313.1 311.8 310.6 131.2 
50 322.8 321.5 320.2 319.0 317.7 316.4 315.2 313.9 312.7 311.4 310.2 164.0 
75 321.7 320.4 319.1 317.9 316.6 315.3 314.1 312.9 311.6 310.4 309.2 248.1 
100 320.6 319.3 318.0 316.8 315.5 314.2 313.0 311.8 310.5 309.3 308.1 328.1 
150 318.3 317.0 315.8 314.5 313.3 312.0 310.8 309.6 308.4 307.2 306.0 492.1 
200 316.1 314.9 313.6 312.4 311.1 309.9 308.7 307.5 306.3 305.1 303.9 656.2 
250 313.9 312.7 311.5 310.2 309.0 307.8 306.6 305.4 304.3 303.1 301.9 820.2 
300 311.7 310.5 309.3 308.0 306.8 305.6 304.5 303.3 302.2 301.0 299.9 984.3 
350 309.5 308.3 307.1 305.9 304.7 303.5 302.4 301.2 300.1 298.9 297.8 1,148.0 
400 307.3 306.1 305.0 303.8 302.7 301.5 300.4 299.2 298.1 296.9 295.8 1,312.0 
450 305.2 304.0 302.9 301.7 300.6 299.4 298.3 297.2 296.0 294.9 293.8 1,476.0 
500 303.0 301.9 300.7 299.6 298.4 297.3 296.2 295.1 294.1 293.0 291.9 1,640.0 
600 298.8 297.7 296.6 295.5 294.4 293.3 292.2 291.2 290.1 289.1 288.0 1,969.0 
700 294.6 293.5 292.5 291.4 290.4 289.3 288.3 287.2 286.2 285.1 284.1 2,297.0 
800 290.5 289.5 288.4 287.4 286.3 285.3 284.3 283.3 282.3 281.3 280.3 2,625.0 
900 286.5 285.5 284.5 283.4 282.4 281.4 280.4 279.4 278.5 277.5 276.5 2,953.0 
1,000 282.5 281.5 280.5 279.5 278.5 277.5 276.6 275.6 274.7 273.7 272.8 3,281.0 
1,500 263.3 262.5 261.6 260.8 259.9 259.1 258.3 257.5 256.6 255.8 255.0 4,921.0 
2,000 245.4 244.7 244.0 243.2 242.5 241.8 241.1 240.4 239.7 239.0 238.3 6,562.0 
—22.0 — 20.2 —18.4 — 16.6 -14.8 —13.0 -11.2 —9.40 —7.60 — 5.80 — 4.00 N h (ft) 
tF\ 
TaBLe 8B. H for? from —20 C (—4 F) to —10 C (+14 F); h to 2,000 m (6,562 ft). 
po = 1,000 mb at sea level : 
\ie> 
h (m)\, —20 -19 -18 -17 —16 -—15 —14 —13 —12 -ll —10 h (ft) 
0.0 
32.8 
65.6 
98.4 
131.2 
164.0 
248.1 
328.1 
492.1 
656.2 
820.2 
984.3 
1,148.0 
1,312.0 
1,476.0 
1,640.0 
1,969.0 
2,297.0 
2,625.0 
2,953.0 
3,281.0 
4,921.0 
6,562.0 
\ a (ft) 
tF\ 
-4.00 -2.20 -040 +140 +3.20 +5.00 +680 +860 +10.4 
+12.2 +14.00 
