A preliminary analysis for down-looking radar location

The critical depression angle for down-looking radar location is an important parameter, which is function of refractive index on ground surface and that at radar height. When the initial depression angle is less than or equal to the critical depression one, the ray path is reversed up-ward in space, its reversing height is related to the initial depression angle and refractive index. Based on the radiosonde data measured in our country, atmospheric refraction modification for down-looking radar location is analyzed, the method for calculating reversing height is also presented in this paper.