Camilo Younes

Contribution to Lightning Parameters Study Based on Some American Tropical Regions Observations

This paper presents a recent characterization review of three cloud-to-ground lightning parameters [lightning peak current, ground flash density, and keraunic level (KL)] used in engineering applications based on available data from studies conducted in some tropical countries of Central and South America (Brazil, Colombia, Costa Rica, and Venezuela), considering seasonal and spatial variation aspects. There are some differences between the behaviors of the analyzed parameters in tropical areas in comparison with those published in the literature for temperate ones. The most significant conclusion is that historical data suggest that the highest ground flash density are located between latitude of 8° and 10° north. This value is much higher than the highest values reported for countries located in temperate regions. It is seen from the KL analysis that this parameter varies depending on the latitude with values up to 200 thunderstorm days (TDs).

Electromagnetic fields generated by lightning channels with tortuosity and its effect on the time-of-arrival technique

In this paper it is presented a simulation analysis of electric fields generated by lightning channels with tortuosity. The tortuosity of the channel is reproduced by means of a numerical algorithm that takes into account statistical characterizations made by different authors observing real lightning channels, so the macroscale tortuosity of the simulated channel is similar to the one recorded in nature. Later it is used an analytic model which allows the calculation of the electromagnetic fields generated by lightning channels with tortuous geometries, once the geometry is known. The electromagnetic fields are calculated assuming a Heaviside step function as the current traveling along the channel. The objective of this work is to analyze two factors that could cause error in the time-of-arrival technique for lightning localization: the change in the electromagnetic wave shape around the channel and changes in the magnitudes of the measured fields for the same distance from the base of the channel but different azimuth angle.

A meteorological variables study and its correlation with thunderstorm activity over medellin city(Colombia)

The present study shows an analysis of how the atmosphere affects the thunderstorm formation in Medellin City (Colombia). To carry out this study a meteorological station located in Olaya Herrera Airport and a LINET Lightning Locating System network were used. To understand the atmosphere role, atmospheric pressure, near surface air temperature, dew point temperature and wind measurements are used. Results show that more than 60% of total lightning are present during the periods of March-April-May and September-October-November. This study ratify that Medellin is a city with one of the highest lightning activity in the world with 202 thunderstorm days in average. Additionally, the diurnal cycle of lightning activity shows that for all the analyzed periods more than 50% of lightning detected are present between 11:00 and 17:00 hours in local time.

Equidad, Accesibilidad y Transporte. Aplicación explicativa mediante un Análisis de Accesibilidad al Sector Universitario de Manizales (Colombia)

espanolVn esta investigacion se analiza la posicion geoespacial del principal sector universitario de la ciudad de Manizales a su relacion con las caracteristicas operativas de la red de transporte a el estrato de sus principales usuarios (estudiantes a docentes). La metodologia aplicada se basa en cuatro etapas teniendo como objetivo el analisis de accesibilidad media integral ofrecida por la red de transportes a la comunidad universitaria, a traves de un modelo geoestadistico. Se encontro que los estudiantes que viven en barrios de estrato bajo son los que deben invertir mas tiempo para desplazarse hacia la Universidad, situacion contraria a la obtenida con los estudiantes a docentes que residen en barrios de estrato alto. Los resultados expresan la inequidad espacial que se refleja en altos tiempos de viaje, asi como la ausencia de posibilidades reales de llegar al sector universitario, concluaendo que es necesario el ampliar la variedad de trasporte a mejorar la calidad de los modos de transporte que llegan a dicho sector desde la residencia de estudiantes a docentes. EnglishIn this research, the geospatial position of the main universita sector of the cita of Manizales and its relation with the operational characteristics of the transport network and the strata of users (students and teachers) is analazed. The applied methodologa is based on four stages with the target of knowing the integral average accessibilita offered ba the transport network to the universita communita, through a geostatistical model. The studa showed that students who live in neighborhoods of lower strata have to invest more time to go to the Universita. The results obtained with students and teachers who live in neighborhoods with high stratum situation is the opposite, consuming less travel time. The results show the spatial inequalita which is reflected in high travel times, and the lack of real possibilities to arrive in the universita sector. It is concluded that it is necessara to expand the varieta of transport and to improve the qualita of transport modes that come to this sector from the residence of students and teachers.

Lightning activity behavior over Bogota - Colombia due to urban effect

This paper presents the lighting activity behavior over Bogota (Colombia) and its comparison with some adjacent regions due to urban effect. The study was developed using a methodology presented by Jvar and others in [1]. In order to achieve the goals, 6 years of lightning data from SID (one of the Colombian lighting location systems) and particulate matter PM10 data from the Air (Quality Network of Bogota - RMCAB were used. the results show an increase of lighting activity over Bogota on approximately 200% during the evaluated period.

Does exist any relationship between the thunderstorm that occurred on march 30, 2012 in the Manizales city and the activity of the Nevado del ruíz volcano?

This paper presents an analysis of the thunderstorm that occurred in the Manizales city in Colombia, on March 30, 2012 and makes an evaluation of the possible relationship between the lightning activity of that thunderstorm and the high volcanological activity registered in the Nevado del Ruíz volcano at the same city. This paper uses data obtained from the Lightning Location Network (LINET), World Wide Lightning Location Network (WWLLN) and the Volcanological and Seismological Observatory of Manizales (OVSM).

Influence of non flat terrain on lightning induced voltages in distribution networks

This paper presents the effect of the terrain in lightning induced voltages in distribution networks. For this, we have calculated the electromagnetic fields over two different non flat terrains configurations, by means of the Finite difference time domain (FDTD) method in a two dimensional (2D) cylindrical coordinate system. We have simulated a typical distribution network placed over these terrains and we have calculated the lightning induced voltages in these lines by means of the Agrawal Coupling Model. It can be seen important differences between the lightning induced voltages produced on mountain zones respect to the traditional calculation considering the terrain as flat.

Influence of the geometry of the discharge channel in a model for the first return stroke

This paper examines the influence of the lightning channel geometry, and the variation of the linear charge density with height, in a model for the first return stroke. The tortuous geometry of the discharge channel is simulated by means of statistical characterizations of natural lightning reported in the literature. The linear charge density for a channel with a tortuous geometry is modeled by means of a regression analysis of simulated data. Finally, the results presented, show a comparison between the spatio-temporal distribution of currents along a straight and vertical channel with those of a tortuous channel with non-homogeneous linear charge density.

Lightning performance of overhead distribution network assessment using fuzzy ground flash density concept

This paper will deal with the lightning performance of a distribution network, using the new concept to calculate the ground flash density (GFD). It is called fuzzy ground flash density (FGFD), and it allow to take into account the factors that can affect the traditional way to calculate the GFD, such as the area chosen and the hard variation for two points geographically adjacent.