Fractal and multifractal concepts are promising tools for characterizing hydraulic properties in soils. The application of one method or the other will depend on the distributión and type of variability of the properties that are being studied. The saturated hydraulic conductivity (K,) is an important soil physics parameter to establish fluid transpon in soils. The measurement of hydraulic conductivity in the laboratory has showed to be much influenced by column size. In this work we have applied multifractal theory to study the dependence of column sample size in three different soil horizons (Ap. c. and C2) and along of a transect. The multifractal parameters calculated were functions of both sample length and sample area. Smaller volumes, resulting from shorter samples or smaller area perpendicular to flow, exhibited more heterogeneous distribution and, therefore, stronger multifract...

Ver PDF

The Total Solar Irradiance (TSI) is the total amount of solar energy  present per square unit every moment beyond the atmosphere, so it's changing every time along the year, although for many practical purposes its average is taken and has been called:  The Solar Constant (1367 W/m2). In this paper, the historical efforts made to quantifcate the TSI are reviewed, the latest advances in this matter are presented and a new method to calculate its monthly average based on the SunSpot Number is proposed to apporach to its value as close as 0.05. W/m2 (RMS = 0.002).

La Irradiancia Solar Total Extraterrestre (TSI) es la cantidad total de energía solar por unidad de área presente en cada momento fuera de la atmósfera terrestre; por lo tanto, varía a lo largo del año, sin embargo, para muchos fines prácticos se la considera constante y se le asigna el valor de la llamada Constante Solar (1367 W/m2). En este artículo se revisan los esfuerzos históricos hechos para cuantificar la Irradiancia Solar Total Extraterrestre, se presentan los últimos avances en esta materia y se propone un método que permite estimar su valor promedio mensual a partir del número de manchas solares, con una incertidumbre de 0.05 W/m2 (RMS ~ 0.002).

Total Extraterrestrial Solar Irradiance (TSI) is the amount of energy from the sun, per unit area, received by every point above the Earth's atmosphere, at each instant of time; therefore, it is a quantity that varies both spatially and temporally, according to the position of a particular point on Earth and its position with respect to the Sun. A series of methodological proposals are currently available to estimate TSI on a daily basis, however, there are places such as Antarctica, where the synoptic variability is very high, therefore, it is necessary to adapt or develop a methodology that allows an energy balance to be carried out on a shorter time scale. Henceforth, the adaptability at the hourly level of the most important models proposed at the daily level will be analyzed and, finally, a methodology will be proposed to be used in studies of high spatial and temporal resolution, s...

Total Extraterrestrial Solar Irradiance (TSI) is the amount of energy from the sun, per unit area, received by every point above the Earth's atmosphere, at each instant of time; therefore, it is a quantity that varies both spatially and temporally, according to the position of a particular point on Earth and its position with respect to the Sun. A series of methodological proposals are currently available to estimate TSI on a daily basis, however, there are places such as Antarctica, where the synoptic variability is very high, therefore, it is necessary to adapt or develop a methodology that allows an energy balance to be carried out on a shorter time scale. Henceforth, the adaptability at the hourly level of the most important models proposed at the daily level will be analyzed and, finally, a methodology will be proposed to be used in studies of high spatial and temporal resolution, s...

Se describe la aplicación de un nuevo método para la completación de datos faltantes de precipitación diaria utilizando la “Transformada de Wavelets” (TW). Series completas de datos de precipitación diaria para los períodos 1999-2000, 2003-2004, 2004- 2005, seis estaciones meteorológicas del altiplano peruano fueron utilizadas en el análisis. El proceso consistió en la descomposición y reconstrucción de la señal, a dos niveles, usando el Wavelet Haar. El programa desarrollado utiliza la señal que resulta del filtro de baja frecuencia, proveniente de la estación a ser corregida y el detalle o señal de alta frecuencia proveniente de una estación vecina, la que proporciona el detalle aleatorio que se usa en el llenado de datos faltantes. La selección de la estación vecina se basó en la similitud de la distribución acumulada de ambas señales previamente estandarizada...