Chapter 9. Radio-Meteorological Charts, 

 Graphs, Tables, and Sample Computations 



9.1. Sample Computations of Atmospheric 

 Refraction 



The following problem will serve to illustrate the a})plication of the 

 various methods of calculating bending of a radio ray as described in 

 chapter 3. A particular daily set of RAOB readings from Truk in the 

 Caroline Islands yields the following data: 



Height above the 

 surface (km) 

 0.000 

 0.340 

 0.950 

 3.060 

 4.340 

 5.090 

 5.300 

 5.940 

 6.250 

 7.180 

 7.617 

 9.660 

 10.870 



What is the total bending up to the 3.270-km level at initial elevation 

 angles of 0°, 10 mrad, 52.4 mrad (3°), and 261.8 mrad (15°) by (a) Schul- 

 kin's approach, (b) the exponential model, (c) the initial gradient method, 

 (d) the departures from normal method, (e) the use of regression lines, 

 and (f) the graphical method of Weisbrod and Anderson? Since the 

 gradient between the ground and the first layer is 



AA^ 365.0 - 400.0 ,nooAr •. /i 



71 = rv nAr. = — 102.9 A' umts/km, 



An 0.340 



and this is a decrease of N per kilometer that is less than the —157 N 

 units/km required for ducting, no surface duct is {)resent. However, 



375 



