EXTENSION TO OTHER REGIONS 



331 



The preceding analysis of bending throws the refractive differences in 

 each case into sharp rehef. The effect of refraction, of course, is to vary 

 the ray path. Figures 8.14 and 8.15 show the ray paths corresponding 

 to the bendings of figures 8.12 and 8.13. Note that for Canterbury at 

 ^0 = mrad, the effect of the horizontal variation of n is to produce a 

 difference in estimation of about 1 km in height or 20 km in ground dis- 

 tance at 300 km from what would be obtained from considering the verti- 

 cal n profile as a representation of the entire path. The effect of the 

 subrefractive layer at Cape Kennedy is not so large, but it does cause an 

 overestimation of the ground distance by about 5 km and an underesti- 

 mation of the height by less than one quarter of a kilometer at a ground 

 distance of 300 km by assuming that the vertical profile may be used 

 throughout the entire ray path. 



8.2.6. Extension to Other Regions 



It should be pointed out that the ducting case at Canterbury represents 

 an extreme refraction condition and is not necessarily typical of conditions 

 observed in other regions or, indeed, at Canterbury. The Canterbury 

 project was purposely restricted to a study of ducting conditions with the 

 result that less than 20 percent of the total observations for the fifteen 



Corrected exponential reference 

 atmosphere 



Path of Canterbury vertical ray 



Path of Canterbury horizontal ray 



120 160 200 240 



DISTANCE IN KILOMETERS 

 Figure 8.14. Canterbury, to 10 km, attitude of ray versus distance. 



