The microphysical properties and evolution in anvils from thunderstorms have long been of great interest in the study of the water budget and radiation transfer in the atmosphere. Recent interest in microphysical processes in anvils near Kennedy Space Center is inspired by the need to understand the temporal and spatial decay of electric fields and microphysical properties in active and decaying anvils. In-situ measurements in anvils from thunderstorms have frequently been curtailed in order to study the most dynamically active portions of convective storms. Consequently little observational data exist from anvil regions of convective storms.

During June 2000 and late May through June 2001 field campaigns were conducted to obtain simultaneous in-situ airborne measurements of electric fields and microphysical content in anvils and anvil debris clouds near Kennedy Space Center using the University of North Dakota Citation jet aircraft. The microphysical measurements provide a comprehensive look at the entire particle spectrum from a few microns to more than a centimeter. The probes include the PMS-FSSP (~3 to 55 microns), the PMS-1D-C (~20 to 600 microns), the PMS-2DC (~33 to 1000 microns), the SPEC Cloud Particle Imager (~10 to 1000 microns), and the SPEC-HVPS (~0.2 to 45 mm). This paper will present microphysical summaries at different distances downwind of the storm cores for some of the cases. Preliminary findings indicate that the aggregation process is an active process at cold temperatures and in most regions of these anvils even far from the core. The study will focus on the aggregation process and how it effects the temporal and spatial evolution of the hydrometer spectrum.