Abstract
A 3-hr flight of a constant-volume balloon which is entrained into a cumulus congestus cloud and lifted to an altitude of nearly 3 km provides an opportunity to determine the trajectory and vertical velocity of the balloon and, in turn, relate these to the circulation of the cloud. Simultaneous supplementary observations by radar, cameras, satellite, and other ground based instruments provide the meteorological context for the event. Computations show that the vertical velocities of the cloud may approach 10 m sec−1, and sustained upward velocities of 3–5 m sec−1 are maintained for considerable periods of time and height. Comparison with a “jet” model shows remarkable agreement, while the “bubble” model would require unreasonably large values of the radius to generate the observed vertical velocities.
