Solar eclipse

Abstract: PV power plants have been recently installed in very large scale. So the effects of the solar eclipse are of big importance especially for grid connected photovoltaic (PV) systems. There was a partial solar eclipse in Prague on 20th March 2015. We have evaluated the data from our facility in order to monitor the impact of this natural phenomenon on the behavior of PV system, and these results are presented in the paper. The behavior of PV system corresponds with the theoretical assumption. The power decrease of the PV array corresponds with the relative size of the solar eclipse. - characteristics of the PV panel correspond to the theoretical model presented in our previous work.

Abstract: Measurements of the electric field, the vertical current density, space charge and conductivity have been carried out at five ground stations and three series of free-air measurements during the 7 March 1970 solar eclipse in and near the totality zone. The problem whether the observed variations in electric parameters are caused by near-ground processes (related to eddy diffusion) or by highaltitude processes is not yet solved. It was possible, however, to offer a speculative explanation with the first assumption for the majority of the observations. The most important conclusion is the ecquisition of a better understanding of the requirements for measurements made for investigating solar eclipse effects. Also, it seems that simple models are not sufficient to explain the sequence of variations seen in the data.

Abstract: Observations of the NO2 and O3 columns using zenith-viewing differential absorption spectroscopy in the visible range (450–540 nm) were carried out at Izana Observatory (Tenerife, 28°N, 16°W, 2370 m above sea level.) during the eclipse of February 26, 1998 (95% occultation over the station). Ozone has been retrieved using two different spectral ranges to minimize the effect of the continuous change of the solar spectrum shape as the Sun is being occulted. Small variations before the maximum phase in agreement with previous observations are found, but because of the change in the shape of the solar spectrum, it cannot conclusively be determined whether the ozone changes are real or due to interferences with changing Fraunhofer lines. The difficulties in observing small changes of absorbing gases during solar eclipse when using remote sensing technique that uses the solar UV and visible radiation as the source are discussed. NO2 displays an increase in phase with the degree of solar occultation, as compared to a non eclipse day of 1.55±0.09. A simple model assuming that changes over short times scales are only due to changes in photodissociation, using O3 and temperatures obtained from an ozone sounding station close to the observatory, reproduces the observed variation when the NO2 bulk is assumed to be at an altitude of 28 km. Correction for differences between local solar zenith angle (SZA) and the SZA where the absorption takes place is taken into account.