REFRACTIVE INDEX PARAMETERS 



185 



09 



10 



11 



12 

 PST 



13 



14 



15 



Figure 5.7. X-band signal level versus time. 

 Santa Barbara X-band signal level for 26 Mar. 1958. 



Moler and Holdeii then continue with a description of the large signal 

 enhancement and deep fading that occur as the propagation mechanism 

 varies between partial reflection and scattering on a transhorizon radio 

 path along the California coastline. Reflection occurs when strong re- 

 fracting layers are present within a kilometer of the surface, typifying 

 meteorological conditions generally associated with the subsidence inver- 

 sion frequently found along the California coast. 



Figure 5.6 shows the sea level pressure chart and a series of streamline 

 analyses by Moler and Holden depicting mesoscale centers of convergence 

 and divergence for a day in March along the southern California coast. 

 Figure 5.7 shows the X-band signal level received at Point Loma, San 

 Diego (SD) from Santa Barbara (SB) during the same day. As the 

 centers of convergence along the radio path weaken, refractive layers are 

 formed and the signal level rises sharply during the middle of the day. 

 Later the signal level lowers again with the regeneration of convergence 

 centers and the destruction of stratified layers during the afternoon hours. 



5.3. Refractive Index Parameters 



In later sections, the analysis of a synoptic disturbance in the tropo- 

 sphere will be described in detail. Certain reduced forms of the refrac- 

 tive index that will be useful in the ensuing discussion will be developed 

 here. These forms, already discussed in chapter 1, are revisited here for 

 the purj)ose of com])arison in synoptic example. 



