Experimental Size Spectra Research Articles

Rainfall Microphysics and Radar Properties: Analysis Methods for Drop Size Spectra

Abstract Analyses are performed of experimental drop size spectra to explore the relationships among integral parameters for rain. The data used in this work were acquired with an airborne optical 2D precipitation probe in TOGA COARE during a 4-month period in 1992–93. It is assumed that the experimental size spectra can be described by a gamma drop size distribution (DSD) of the form N(D) = N0Dμ exp(−ΛD) involving three parameters (N0, μ, Λ), which are determined using a new method of truncated moments. The method allows for truncation of the DSD at the large-diameter end of the spectrum due in part to instrumental effects and also in part to the trajectory of the aircraft through a rain streamer that has been sorted by wind shear. An effect analogous to truncation can occur at the small-diameter end of the size spectrum due to evaporation. However, truncation of the spectrum at the small-diameter end is not considered in this work. It is found that spectra with small space and timescales display conside...

Analysis of Doppler Radar Spectra of Hail

Methods of analysis are described which determine the two parameters in an assumed exponential hailstone size distribution from the Doppler radar spectrum. When applied to the data of Battan and Theiss it is found that these methods yield computed exponential distributions and experimental size spectra which are in very good agreement, and that the various methods of analysis are in substantive agreement when the maximum hailstone diameter is at least 2 cm.