366 



REFRACTION AND REFRACTIVE INDEX MODELS 



In figures 8.29 through 8.33 the contours do not extend below 15,000 ft 

 for distances greater than 120 mi and 10,000 ft for distances greater than 

 80 mi. Correlations were not calculated for these target positions, be- 

 cause for certain refractive index profiles they are beyond the radio 

 horizon and for certain other profiles the arrival angle is too low for the 

 ray to penetrate a trapping layer. If conditions exist, without violating 

 the assumptions of sections 8.4.2. through 8.4.4. such that a target at 

 5000 ft height and 150 mi distance would be visible to radar, the resulting 

 height error would be about 10,000 ft. 



Figure 8.31. Standard error of eh versus Ng 



40 150 160 



Figure 8.32. Standard error of th versus Ng and Go. 



