Mountain pastures dominated by the pasture grass Setaria sphacelata in the Andes of southern Ecuador are heavily infested by southern bracken (Pteridium arachnoideum), a major problem for pasture management. Field observations suggest that bracken might outcompete the grass due to its competitive strength with regard to the absorption of photosynthetically active radiation (PAR). To understand ...

We used radiation data taken during the Atmospheric Radiation Measurement (ARM) Enhanced Shortwave Experiment (ARESE). We constructed the total irradiance by adding the average diffuse field irradiance measured by two shaded pyranometers and the direct beam irradiance multiplied by the cosine of the solar zenith angle. We used an empirical formula introduced by Michalsky et al. (1997) to correc...

—HelioClim-3 is a database containing surface solar irradiance assessed every 15 min from images taken by the Meteosat series of satellites since 2004. It covers Europe, Africa and Atlantic Ocean. In average, comparison with hourly measurements made in meteorological stations yields a correlation coefficient greater than 0.9, a relative root mean square error (rRMSE) around 20% of the mean meas...

The estimation of global solar radiation incident on the earth’s surface is an important issue for several solar-based applications. From a signal processing point of view, it falls within nonstationary, non-linear/non-Gaussian dynamical inverse problems. In this paper, we propose a sequential Monte Carlo state space approach combining satellite images and in situ data. We propose original obse...

Apparent evidence for a strong signature of solar activity in ground-based insolation data was recently reported. In particular, a strong increase of the irradiance of the direct solar beam with sunspot number as well as a decline of the brightness of the solar aureole and the measured precipitable water content of the atmosphere with solar activity were presented. The latter effect was interpr...

In this paper a simulation to maximize the global solar radiation on a sloped collecting surface was applied to typical latitudes in the area of southern Italy, to calculate the optimum tilt angle of solar panels on building structures or large photovoltaic power plants located in that geographical area. Indeed, the area of southern Italy and in particular Sicily and Calabria are the top of Eur...

Due to non-homogeneous mass distribution and non-uniform velocity rate inside the Sun, the solar outer shape is distorted in latitude. In this paper, we analyze the consequences of a temporal change in this figure on the luminosity. To do so, we use the Total Solar Irradiance (TSI) as an indicator of luminosity. Considering that most of the authors have explained the largest part of the TSI mod...

The purpose of this work is to present a simple global solar irradiance forecasting framework based on the optimization of the k-nearest-neighbors (kNN) and artificial neural networks algorithms (ANN) for time horizons ranging from 15 min to 2 h. We apply the proposed forecasting models to irradiance from five locations and assessed the impact of different micro-climates on forecasting performa...

Variations in solar activity, at least as observed in numbers of sunspots, have been apparent since ancient times but to what extent solar variability may affect global climate has been far more controversial. The subject had been in and out of fashion for at least two centuries but the current need to distinguish between natural and anthropogenic causes of climate change has brought it again t...

Solar panels sustainably harvest energy from the sun. To improve performance, panels are often equipped with a tracking mechanism that computes the sun’s position in the sky throughout the day. Based on the tracker’s estimate of the sun’s location, a controller orients the panel to minimize the angle of incidence between solar radiant energy and the photovoltaic cells on the surface of the pane...