Polarimetric Weather Radar Analyses of the Christmas Freezing Rain Storm at Vienna International Airport

On 23 December 2012, a warm front passed over Austria accompanied by significant, long lasting freezing rain which affected entire operation at the Vienna airport. The transition from snow toward ice pellets and subsequent freezing rain and warm rain is explored using quasivertical profiles (QVPs) of operational C-band polarimetric radar data. Results reveal important insights into the evolution of the melting layer and cloud microphysical processes which lead to precipitation formation.

The QVP analyses are represented in a height vs time format which offers the possibility for comparison to vertically pointing ZDR calibration scan and wind profiler data. The study is complemented by the sensitivity analyses of the QVP methodology to the choice of antenna elevation angles and the radome influence due to accumulated ice.

Nowcasting applicability is demonstrated using trend and structural analyses of these QVPs also in comparison to upstream situated radar sites. Significant differences in the melting layer heights estimated from QVPs and numerical forecast model were observed. Mesocale frontal boundaries are resolved in the ZDR and ρhv QVPs with high spatial / temporal resolution which helps to distinguish between different precipitation types and their evolution. This illustrates strong potential of the QVP methodology for nowcasting of disruptive weather in terminal areas of airports.

DOI: 10.1127/metz/2016/0807