Effects of temperature gradient and radial range decay on the spectrum analysis of the radio acoustic sounding system using FM CW radar

Abstract

To develop the theory of FM CW radio acoustic sounding system (RASS), in this paper an analysis of influences from temperature gradient and radial range decay is presented. A nonconstant temperature gradient will significantly modify the spectrum of scattered signals and also cause a deviation of the maximum position of amplitude spectrum from the Bragg resonance, which should involve using any retrieval algorithm that will correct for this temperature bias. Without considering this effect, the error of 0.5–1 K will probably be introduced in the RASS temperature profile. An approximate retrieval algorithm is provided in text. Moreover, for the application of RASS using FM CW radar in lowest 100‐ to 200‐m atmosphere, the far‐field aspect sometimes will not be the case, and radial range decay will play a certain role, which is investigated also in this paper.