Lightning in Western Patagonia

On the basis of 8 years (2005-2012) of stroke data from the World Wide Lightning Location Network we describe the spatial distribution and temporal variability of lightning activity over Western Patagonia. 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, and features a hyper-humid, maritime climate. Stroke density exhibits a sharp maximum along the coast of southern Chile. Although precipitation there is largely produced by cold nimbostratus, days with more than one stroke occur up to a third of the time somewhere along the coastal strip. Disperse strokes are also observed off southern Chile. In contrast, strokes are virtually nonexistent over the austral Andes -where precipitation is maximum- and farther east over the dry lowlands of Argentina. Atmospheric reanalysis and satellite imagery are used to characterize the synoptic environment of lightning-producing storms, exemplified by a case study and generalized by a compositing analysis. Lightning activity tends to occur when Western Patagonia is immersed in a pool of cold air behind a front that has reached the coast at ~40°S. Under these circumstances, midlevel cooling occurs before and is more prominent than near-surface cooling, leading to a weakly unstable postfrontal condition. Forced uplift of the strong westerlies impinging on the coastal mountains can trigger convection and produces significant lightning activity in this zone. Farther offshore, large-scale ascent near the cyclone's center may lift near-surface air parcels, fostering shallow convection and dispersing lightning activity.publishedVersionFil: Bürgesser, Rodrigo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Ávila, Eldo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Bürgesser, Rodrigo E. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Ávila, Eldo E. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Garreaud, René D. Universidad de Chile. Department of Geophysics and Center for Climate and Resilience Research; ChileFil: Nicora, M. Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Nicora, M. Gabriela. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Meteorología y Ciencias Atmosférica

Lightning activity in the Southern Coast of Chile

Ponencia presentada en la XV International Conference on Atmospheric Electricity, 15-20 June 2014, Norman, Oklahoma, U.S.A.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.Fil: Nicora, M. Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Nicora, M. Gabriela. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Quel, Eduardo J. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Quel, Eduardo J. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Bürgesser, Rodrigo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Bürgesser, Rodrigo E. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Ávila, Eldo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Ávila, Eldo E. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Garreaud, René D. Universidad de Chile. Department of Geophysics; ChileFil: Garreaud, René D. Center for Climate and Resilience Research; ChileInvestigación Climatológic

La actividad eléctrica atmosférica en Argentina : estimación de la tasa de mortalidad anual por acción de caídas de rayos

Disponer de información de la actividad eléctrica en el territorio nacional es un elemento fundamental para la vigilancia atmosférica. Tanto para aplicaciones de relevancia, en cuestiones de seguridad e infraestructura, así como variable meteorológica, los valores de días de tormenta en las diferentes regiones del país, son una herramienta simple y poderosa para poder evaluar la atmósfera y losfuturos cambios en ella.Los objetivos del presente trabajo son realizar un estudio de la evolución de la eficiencia de detección de descargas eléctricas de la red global terrestre World Wide LightningLocation Network (WWLLN) dentro del territorio nacional, comparar los datos de dicha red con los datos suministrados por el SMN y, en función de la evaluación de dicha información, confeccionar los mapas isoceraúnico de la República Argentina para el periodo 2005-2012.Estos datos se utilizan para estimar la tasa de mortalidad anual por un rayo en la región. La estimación se basa en un modelo propuesto por Gomes Chandima, y Ab Kadir [1]. Los resultados obtenidos podrían ayudar a fomentar conductas de protección en la población.To have information of electrical activity in the country is a key element for atmospheric monitoring. In the fields of applications in security and infrastructure issues and weather variables, the values of stormy days in different regions of the country are a simple and powerful tool to evaluate the atmosphere and future changes. The objectives of this study are to conduct a study of the evolution of the efficiency of lightning detection global terrestrial network World Wide Lightning Location Network (WWLLN) within the country, comparing this data with the supplied by the SMN and, depending on the evaluation of that information, make isoceraunics maps of Argentina for the period 2005-2011. These data are used to estimate the annual death rate by lightning in the region. The estimation is based on a model proposed by Chandima Gomes, and AbKadir [1]. The obtained results could help to promote protective behaviors in the population.http://anales.fisica.org.ar/journal/index.php/analesafa/article/view/1995https://anales.fisica.org.ar/journal/index.php/analesafa/article/view/1995publishedVersionFil: Nicora, M. Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Nicora, M. Gabriela. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Quel, Eduardo J. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Quel, Eduardo J. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Nicora, M. Gabriela. Instituto Franco Argentino de Estudios sobre el Clima y sus Impactos; ArgentinaFil: Quel, Eduardo J. Instituto Franco Argentino de Estudios sobre el Clima y sus Impactos; ArgentinaFil: Salvador, Jacobo O. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigaciones en Láseres y Aplicaciones; Argentina.Fil: Salvador, Jacobo O. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigaciones en Láseres y Aplicaciones; Argentina.Fil: Bürgesser, Rodrigo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Ávila, Eldo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Bürgesser, Rodrigo E. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Ávila, Eldo E. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Rosales, Alejandro. Universidad Nacional de la Patagonia. Facultad de Ingeniería. Departamento de Física; ArgentinaFil: D’Elia, Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: D’Elia, Raúl. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: D’Elia, Raúl. Instituto Franco Argentino de Estudios sobre el Clima y sus Impactos; ArgentinaMeteorología y Ciencias Atmosférica

Changes in the surface irradiance during the total solar eclipse 2020 in Valcheta, Argentina

On December 14, 2020, southern South America experienced a total solar eclipse close to the solar noon. The path of totality, about 90 km wide, extended over the continental region from the Chilean west coast to the Argentine east coast, passing through the provinces of Neuquén, Río Negro and the extreme south of Buenos Aires. In order to study the effects on the atmosphere produced by the total eclipse, the Servicio Meteorológico Nacional Argentino (SMN) and Instituto de Investigaciones Científicas y Técnicas para la Defensa (CITEDEF) carried out a surface radiometric monitoring campaign in Valcheta (40.69°S; 66.15°W), Río Negro, Argentina. In this work, we explore the global surface solar irradiance on a horizontal plane (GHI) with the main objective of quantifying the changes in this parameter for cloudy and clear sky atmospheric conditions, combining ground-based measurements and modeling. A solar limb-darkening function was successfully implemented in the calculation of the irradiance at the top of the atmosphere (TOA) during the eclipse. We estimated a significant GHI attenuation of 41 % between the first (C1) and last (C4) contacts of eclipse compared to similar atmospheric conditions without the total eclipse, which represent a daily reduction of 12 %. In terms of irradiation, a reduction of 3360.1 KJ/m2 was calculated

Studies of the mass composition of cosmic rays and proton-proton interaction cross-sections at ultra-high energies with the Pierre Auger Observatory

In this work, we present an estimate of the cosmic-ray mass composition from the distributions of the depth of the shower maximum (Xmax) measured by the fluorescence detector of the Pierre Auger Observatory. We discuss the sensitivity of the mass composition measurements to the uncertainties in the properties of the hadronic interactions, particularly in the predictions of the particle interaction cross-sections. For this purpose, we adjust the fractions of cosmic-ray mass groups to fit the data with Xmax distributions from air shower simulations. We modify the proton-proton cross-sections at ultra-high energies, and the corresponding air shower simulations with rescaled nucleus-air cross-sections are obtained via Glauber theory. We compare the energy-dependent composition of ultra-high-energy cosmic rays obtained for the different extrapolations of the proton-proton cross-sections from low-energy accelerator data

Study of downward Terrestrial Gamma-ray Flashes with the surface detector of the Pierre Auger Observatory

The surface detector (SD) of the Pierre Auger Observatory, consisting of 1660 water-Cherenkov detectors (WCDs), covers 3000 km2 in the Argentinian pampa. Thanks to the high efficiency of WCDs in detecting gamma rays, it represents a unique instrument for studying downward Terrestrial Gamma-ray Flashes (TGFs) over a large area. Peculiar events, likely related to downward TGFs, were detected at the Auger Observatory. Their experimental signature and time evolution are very different from those of a shower produced by an ultrahigh-energy cosmic ray. They happen in coincidence with low thunderclouds and lightning, and their large deposited energy at the ground is compatible with that of a standard downward TGF with the source a few kilometers above the ground. A new trigger algorithm to increase the TGF-like event statistics was installed in the whole array. The study of the performance of the new trigger system during the lightning season is ongoing and will provide a handle to develop improved algorithms to implement in the Auger upgraded electronic boards. The available data sample, even if small, can give important clues about the TGF production models, in particular, the shape of WCD signals. Moreover, the SD allows us to observe more than one point in the TGF beam, providing information on the emission angle

Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E$^{-2}$ shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E$^{-2}$ be able to explain the observations