The evolution of liquid water/ice contents of a mid-latitude convective storm derived from radar data and results from a cloud-resolving model

Abstract

In a case study the evolution of the liquid water/ice content of an isolated thunderstorm observed by a Cband Doppler radar is investigated. To this end, a 3D cloud resolving mesoscale model is applied yielding the microphysical development of the observed storm including its radar reflectivities. The numerical results are used to derive relations between radar reflectivity Z and cloud mass L which are, on average, valid, on one hand, for mixed-phase cloud regions and, on the other hand, for those containing mostly liquid precipitation particles. These two model-based Z/L-relations are applied for calculating liquid water/ice contents of the observed storm. The liquid water/ice contents such obtained differ significantly from those employing commonly used Z/L-relations. The cloud water inside the cell volume is compared to the maximum available - pseudo-adiabatically determined - showing a good agreement only for the undiluted core of that cell. Finally, the precipitation efficiency is estimated resulting in an upper bound of about 60%.