Retrieval of thermal and microphysical variables in observed convective storms /

Abstract

Preliminary model tests using input from a dynamically simulated cloud establish the accuracy of the retrieval scheme. Real data tests indicate good agreement between retrieved and observed radar reflectivities, qualitative dynamic consistency between observed winds and retrieved buoyancies, and the model's ability to partition liquid and solid hydrometeors. Results further show that the overall echo configuration is controlled by the wind field while echo details are controlled by transients, the wind field, and the cloud microphysics. Recycling of millimetric ice, graupel and drops may strongly modulate storm core precipitation characteristics. Systematic or non-random wind analysis errors are detectable in principle by observing major differences between retrieved and observed reflectivities, provided that other sources of retrieval error are negligible.

The study of air flow in convective storms, the forces that regulate the flow, and the processes that produce hydrometeors of various kinds, are all being studied intensively by meteorologists using Doppler radar observations. The research reported here proceeds from the observed motion through accompanying thermodynamic and microphysical processes to the analysis of hydrometeor content and thermal fields in thunderstorms. A three dimensional numerical kinematic cloud model employing fixed Doppler wind fields, is used to diagnose temperature and mixing ratios and assess the relative importance of the various thermodynamic, microphysical and transportive forcing mechanisms. The microphysical parameterization includes stochastic coalescence effects in warm clouds as well as wet and variable density dry hail growth.