Casebook 6 June 2005


CSU-CHILL Casebook: 6 June, 2005

plot of Virga

Surface conditions were warm and dry when high-based showers occurred in the CSU-CHILL radar coverage area during the afternoon hours of 6 June 2005. Insects flying in the boundary layer generated a widespread low reflectivity / highly positive echo area. Virga or rain shafts that descended into the insect layer caused obvious reductions in the magnitudes. (See VCHILL example below.) is a measure of the reflectivity-weighted mean axis ratio of the scatterers. Thus, as the higher reflectivity raindrops became more common in the radar pulse volume, the values decreased from the insect regime to the rain regime (less than ~ +4 dB).

example in VCHILL

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