32nd Conference on Broadcast Meteorology/31st Conference on Radar Meteorology/Fifth Conference on Coastal Atmospheric and Oceanic Prediction and Processes

Monday, 11 August 2003
Analysis of a strong snowstorm in Catalonia on December 2001
Ramon Pascual, Instituto Nacional de MeteorologŪa, Barcelona, Spain; and A. Callado and M. Berenguer
Poster PDF (245.8 kB)
The strong snowstorm on 14-15 December 2001 which occurred in Catalonia (in the north-east of the Iberian Peninsula) has been examined, focusing our attention on radar information. The storm was associated with a mesoscale cyclogenesis over the Mediterranean Sea that generated a wet onshore low level jet (LLJ). A cold north-easterly advection determined a very low freezing level.

Traffic, electrical supply and, in general, daily life were severely affected in a relatively large and densely populated area. The long duration of the event(more than 40 hours) and the fact that the snow fell at see level were the main characteristics of the storm. The great snow accumulation on the ground was the consequence of both a moderate snowfall intensity and its persistence.

Subjective and objective analysis of radar data (reflectivity and radial velocity volumes) have been done with the goals of diagnosing the main forcing associated to precipitation formation and the impact of this snowstorm on the country. Also, we use this data to describe the time evolution of the precipitation field.

Precipitation accumulation is obtained from raw and corrected data and two different composition methods have been also applied. Although we canít deduce surface snow accumulation directly from this radar product, a first estimation has been obtained and compared with raingauge measurements and visual observations. Because of the presence of a very low freezing level, we make the hypothesis that bright band effects didnít play a major role in degrading snowfall radar field except at the beginning of the event.

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