Abstract: A model of an ascending parcel of air is used to evaluate and demonstrate the accuracy and utility of moment-conserving numerical techniques in cloud microphysical simulations. The sensitivity of the results to parameters ...

Abstract: A numerical cloud modeling project has been initiated as part of METROMEX. A two-dimensional time-dependent model of a vertical slice of the atmosphere has been applied to investigations of cumulus initiation in the St. ...

Abstract: The influence of charge on coalescence was determined in the laboratory for isolated pairs of 340 and 190 ?m water drops failing freely at terminal velocity. A microcomputer-controlled apparatus was used to produce collisions. ...

Abstract: Collisions between small precipitation drops in free fall were analyzed for sizes applicable to self-collection, the process that controls the spreading of precipitation drops to larger sizes. Results from 45 laboratory ...

Abstract: Vast quantities of frequently updated weather data for both forecasting and nowcasting are generally required in meteorological field programs. The continuing synthesis of this data to suit specific operations is best ...

Abstract: Collection efficiencies for accretion were measured for six pairs of nearly unchanged drops. Cloud droplets of 11 and 17 ?m and collector drops between 100 and 400 ?m radius were used. The resulting efficiencies were in ...

Abstract: A closed parcel model which simulates condensation, collection and breakup was used to evaluate the effects of recently measured collection efficiencies on precipitation development. Computations were made using theoretical ...

Abstract: The collection efficiency has been measured for 15 size pairs of relatively uncharged drops in over 400 experimental runs. The results indicate that collection efficiencies fall in a narrow range of 0.60 to 0.70 even though ...

Abstract: Rain triggering mechanisms are evaluated in three microphysical steps: droplet activation on cloud condensation nuclei, droplet growth by condensation, and droplet growth by coalescence. Although considerable progress has ...

Abstract: Observations showed increased concentrations of cloud condensation nuclei (CCN) in air samples collected over and downwind of St. Louis when compared to upwind samples. Aircraft observations of urban clouds showed corresponding ...