Thunderstorm anvils: A close look at their evolution

In July 2002, the CRYSTAL-FACE project in Key West, Florida studied a single isolated anvil cirrus cloud over the course of 3 hours as it evolved from an anvil shield attached to cumulonimbus, to thinning, dissipating cirrus. Aircraft showed that, downwind of the thunderstorm, there was not just one but two layers: above the cirrus anvil lay a much colder and more tenuous layer against the tropopause. While the tropopause cirrus was stable, the anvil cirrus dissipated, mostly from ice crystal aggregation and subsequent precipitation. Overall, results show a tight interplay between cirrus anvil microphysics and dynamics.