Analysis of Clean-Air Echoes Based on Millimeter Wave Cloud Radar Measurements

The millimeter wave cloud radar (MMCR) is capable to detect microparticle features in the cloud and to describe the microphysical structure. Clear-air echo is a major type of false echoes (caused by non-meteorological factors) of MMCR. Therefore, analysis of clear-air echoes is valuable for cloud observation. This work analyzes the physical characteristics of the clear-air echoes, and discusses the possible features which could be extracted from products of four devices: MMCR, laser-ceilometer, L-band radiosonde and all-sky camera. The simulation results show that all the extracted features have different probability distributions for clear-air echoes and meteorological echoes. Therefore, the conclusion of this paper has potential application for identifying clear-air echoes from meteorological echoes.