Investigation of strong acoustic interference on clouds and precipitation in the source region of the Yellow River using KaKu radar

Abstract

Low-frequency acoustic interference in clouds can be regarded as a potential artificial precipitation technology in extreme environmental conditions such as the plateau with low temperature and oxygen content, particularly those areas with altitudes above 4000 m. In this study, 49 field tests were performed in the source region of the Yellow River (SRYR) during the East-Asian summer monsoon to reveal the influence of strong acoustic interference on cloud and precipitation, including the radar reflectivity factor (Z), liquid water content (Lwc), and rain rate (R). Research on precipitation interference and rainfall microphysical results under large-scale acoustic waves were investigated in detail via Ka cloud and KaKu weather radars. Ground-based observations showed that Z, Lwc, and R values were sensitive to acoustic application, especially for stratiform clouds. The effects of acoustic intervention were found to be weakened by severe acoustic attenuation near sampling altitudes of 1200 m. The Z-value difference ranged from −4.18 to −0.31 dBZ for stratiform rain during the East-Asian summer monsoon of the Darlag region of China. The differences in Z, Lwc, and R between operating and monitoring periods of rainfall samples overall decreased with increased height. The average values of Lwc and R with acoustic applications below 1800 m were 0.12 g·m−3 and 2.42 mm·h−1 stronger than that above 1800 m, respectively.