In Situ Microphysical Observations of a Multicell Storm Using a Balloon-Borne Video Disdrometer During Deep Convective Clouds and Chemistry

Abstract

The microphysical characteristics of severe storms and deep convection are challenging but critical in situ observations. Adjustments to modeled microphysical parameters, radar-based hydrometeor classifications, and lightning initiation research all depend on an accurate depiction of real-world particle size distributions. To obtain these observations, a balloon-borne particle imaging device known as the Particle Size, Image, and Velocity probe has been developed at the National Severe Storms Laboratory that is capable of measuring particle size distributions of different particle habits on vertical scales as small as 50 m. The Particle Size, Image, and Velocity observations show that there are rapid shifts in particle counts between successive analysis layers, documenting the small-scale heterogeneity present inside deep convection. Furthermore, when examining functional fits using both a two and three moment scheme on the total distribution as well as individual particle habits, it is clear that a single prescribed parameter space is not adequate to describe the observations collected. When comparing radar reflectivity calculated from the distribution to independent observations from ground based mobile radars, the two sources agree to within 5 dBZ. This provides confidence to the particle density assumptions made here.