Author : Robert George Borchers
Release : 1981
Genre : Cloud physics
Kind : eBook
Book Rating : /5 ( reviews)
Book Synopsis A Computational Study of the Modification of Raindrop Size Distributions in Subcloud Downdrafts by : Robert George Borchers
Download or read book A Computational Study of the Modification of Raindrop Size Distributions in Subcloud Downdrafts written by Robert George Borchers. This book was released on 1981. Available in PDF, EPUB and Kindle. Book excerpt: A computational study is made of the variation of steady-state raindrop-size distributions (0.004 cm less than or equal to radius less than or equal to 0.40 cm) in adiabatic subcloud downdrafts of constant magnitude. The cloud base drop-size distribution is assumed to be Marshall-Palmer. The microphysical processes progressively introduced are evaporation, collision-coalescence, aerodynamic and collisional breakup of drops. Collision-coalescence and breakup area treated through a stochastic model. Thermodynamic and hydrometeoric variables of temperature, relative humidity, total liquid water, rainfall rate and radar reflectivity are computed as functions of height below cloud base along with the drop-size distributions. It is found that evaporation tends to deplete, as expected, the smaller members of the droplet population. Computed raindrop-size distributions agree quite well with measured maritime raindrop spectra reported in the literature, the agreement being better for the higher precipitation rates measured. Other results of the study, as anticipated, are (1) that the downdraft remains unsaturated in the presence of precipitation, the degree of subsaturation increasing with the strength of the downdraft, and (2) that the temperature in the downdraft lies between the moist-adiabatic and the dry-adiabatic lapse rates of temperature.
