A balloon-borne high-definition videosonde to measure thunderstorm microphysics

The microphysics of the upper region of storms, particularly the upper part of the mixed-phase region of storm updrafts, is poorly understood, largely because of the scant in situ measurements available there for various types of storms. These data are needed to verify and improve both the microphysics packages used by numerical cloud models and the hydrometeor classification schemes used with polarimetric radar data. Because the electrification of much of a thunderstorm's updraft is thought to be caused by rebounding collisions between ice particles and riming graupel, better knowledge of mixed-phase microphysics also is needed for studies of lightning and storm electrification. Furthermore, these data will be useful for studies of precipitation development and studies of the effects of precipitation on cloud chemistry. The National Severe Storms Laboratory has developed a balloon-borne high-definition videosonde to determine particle size, shape, phase, and number density. Preliminary data have been collected from a few balloon flights launched into storms in central Oklahoma during the fall of 2009 and 2010, in combination with data from the Oklahoma Lightning Mapping Array. In some cases, polarimetric radar data also are available. This presentation describes the videosonde and presents examples of videosonde data from the balloon flights.