UNIDEF   23986
UNIDAD DE INVESTIGACION Y DESARROLLO ESTRATEGICO PARA LA DEFENSA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Lightning Activity in the Southern Coast of Chile
Autor/es:
NICORA G; BURGESSER R; GARREAUD R; QUEL E
Lugar:
Oklahoma
Reunión:
Conferencia; The Fifteenth International Conference on Atmospheric Electricity (ICAE 2014); 2014
Resumen:
Resumen: ABSTRACT: Based on eight years of lightning data (from January 2005 to December 2012) from the World
Wide Lightning Location Network (WWLLN) we describe the spatial distribution and temporal variability of
lightning activity over southern Chile. This region extends from ~ 40°S to 55°S along the west coast of South
America, is limited to the east by the austral Andes about 100 km inland, and features a maritime climate with
annual mean precipitation in excess of 4000 mm. Cloud electrification is not expected in this region given the
predominance of stable, deep-stratiform precipitation there, but days with at least one stroke occur up to a
third of the time along the coast, being slightly more frequent during late summer and fall. Lightning density
and frequency of lightning days exhibit a sharp maximum along the coast of southern Chile. Disperse strokes
are also observed off southern Chile. In contrast, lightning activity is virtually inexistent over the austral Andes
-where precipitation is maximum- and farther east over the dry lowlands of Argentina. It is suggested that
electrification could develop under weakly unstable conditions that prevail in the region after the passage
of a cold front. Large-scale ascent near the cyclone?s center may lift near-surface air parcels over open
ocean fostering shallow convection, which is enhanced as the strong westerly flow ascend over the coastal
topography. Laboratory experiments of charge transferred during ice crystal-graupel collisions in low liquid
water content conditions and low impact velocity have shown that the non-inductive mechanism can work as
a charge separation process in these systems.