A comparison of buoyancy sorting with the behavior of air in two cumuli

Airborne measurements and observations of the behavior of cloud base air in two cumuli are compared with the results from the Raymond-Blyth buoyancy sorting model. The cloud base air was tagged with a tracer (sulfur hexafluoride) and followed by real-time measurements of the tracer from a research aircraft. The tracer was carried to the top of one cloud and to the midlevels of the other. The model indicated that in the first case parcels of greater than 60% cloud base air were able to rise to the cloud top, while in the second case only parcels with greater than 80% cloud base air would have been able to rise to the top. Frequency distributions of total mixing ratio and wet equivalent potential temperature in the cloud were similar to those predicted by the model in the first 100 mb above cloud base, but diverged at higher levels.