Mantle Echoes Associated with Deep Convection: Observations and Numerical Simulations

摘要

Finescale radar observations of intense thermals/starting plumes, during the early stages of precipitation formation, were collected by an airborne Doppler radar on two separate days. The radar data were recorded as the aircraft flew underneath the developing echoes. Mantle echoes (echoes that often appear as an inverted U shape) were observed on both days. Striking in one of the scans was the resemblance of the echo to a mushroom cloud resulting from a nuclear explosion. Numerical simulations using a two-dimensional cloud-resolving model were run to augment the interpretation of the observations. One of the important conclusions was the proposed modification to the default bulk microphysical scheme used in the model. The default scheme yields "a rush to precipitation" leading to the early establishment of large precipitation contents, which is not supported by the observations. Suggested modifications to the scheme are presented.