GROUND-BASED ATMOSPHERIC DUCTS 



143 



< 260 

 I 



FEB MAY AUG NOV 



FEB MAY AUG NOV FEB MAY AUG NOV 



Months of the Year 

 Figure 4.38. Refractivity gradients of ground-based ducts. 



Table 4.7. Estimated maximum wavelength trapped at do = 



