Different types of rainfall have different heating profiles within the atmosphere and thus classification of rainfall is desirable. Different classifications of rain are characterized by different drop size distributions (DSD) and different temporal characteristics. These features can be detected acoustically allowing acoustic classification of rainfall. The figure shows a comparison of classifications for a tropical thunderstorm. Four rainfall classifications are detected: XC – extreme convection with rainfall rate over 50 mm/hr, TC – transition convection, S1 – stratiform Type 1 (light drizzle) and S2 – stratiform Type 2 (with big drops present). Four classifications are shown: subjective, objective using a Joss-Waldvogel disdrometer, objective using measured acoustic quantities (sound levels and variances of sound levels) and a hybrid acoustic classification using measured acoustic quantities and derived acoustic quantities (rainfall rate, DSD parameters, etc.).

[See Nystuen and Amitai, 2002]