Cumulonimbus vertical velocity events in GATE. Part I: diameter, intensity and mass flux.

Abstract

The statistics are from a total of 104km of flight legs, flown on 6 days in GATE, at altitudes from near the surface to 8100m. For the purpose of study, convective events are divided into 2 categories: drafts, requiring only that vertical velocity be continuously positive (negative) for 500m and exceed an absolute value of 0.5 m-1 for 1 s; and cores, the stronger portions of the stronger drafts, requiring that upward (downward) vertical velocity be continuously greater than an absolute value of 1 m s-1 for 500m. The distributions of average vertical velocity, maximum vertical velocity, diameter and mass flux are given for drafts and cores at 5 altitude intervals between 150m and 8km. In all cases, the distributions are approximately log-normal. -from Authors