Characteristics of the raindrop size distribution on midlatitude mesoscale convective systems

Disdrometer observations during the passage of mesoscale convective systems close to six stations located in Argentina and Brazil are analyzed in order to characterized the raindrop size distribution (DSD). Observations were performed by a PARSIVEL and Thies instruments during different period. A total of 30 convective events were detected during the three year period. Rainfall parameter and statistics of the convective and stratiform region are performed showing DSD evolution in time during different precipitating regimes. The present study reveals that large raindrops are primarily close the convective section but a large increase in small-sized raindrops is also observed. The environment of the events are described using WRF simulations performed at the National Weather Service of Argentina, demostrating that convective areas associated with a wind increase are related with a increase in the standard deviation of the DSD, showing a large variety of drop size categories. Stratiform areas are characterized by a large number small-sized drops.