Sensitivity of modeled hail accretion rates on the lower boundary of the hail spectrum

Abstract

The sensitivity of modeled hail accretion rates on the lower boundary of the hail size spectrum is investigated. Two different expressions for hail terminal velocity are considered: New hail accretion rates consider only hail size particles greater or equal than 0.5 cm (corresponding to the real spectrum); these rates are compared with those derived from an idealized hail spectrum with diameters from 0 to ∞. Sensitivity tests show clearly that the errors in the computation of accretion can be minimized by using the new accretion rates. New accretion rates can differ up to a factor of 77.6 from those based on the idealized spectrum. In addition, it is shown that the accretion rate is sensitive to the expression used for the hail terminal velocity. © by Gebrüder Borntraeger 1996.