Hail formation onset in a cloud, determined by a “window” in the ice absorption index in submillimeter wavelength

Abstract

Three hail-formation phases in a cloud may be detected, by means of MM and SubMM wave propagation analysis in Convective clouds. These phases are size increase of super-large(85 to 1500Μm in radius, and larger) droplets, their transition into supercooled state, and immediate droplets transition into ice or small hail, or their coating by ice Crust. Ice transparency “window” in absorption index, existing in SubMM wave band, is shown to serve as indicator of ice creation in a cloud. Radar reflection coefficient is shown to be increased by two orders of magnitude in the ice transparency “window” under super-large droplets transition into ice.