A reliability and availability model has been developed for a portion of the 4.6 megawatt (MWdc) photovoltaic system operated by Tucson Electric Power (TEP) at Springerville, Arizona using a commercially available software tool, GoldSimTM. This reliability model has been populated with life distributions and repair distributions derived from data accumulated during five years of operation of th...

It has been claimed by others that observed temporal correlations of terrestrial cloud cover with ‘the cosmic ray intensity’ are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We are investigating this claim and our tentative conclusions are to doubt it since our tests so far do not support the hy...

In 2006-2007 the Solar Bolometric Imager (SBI) will operate in the polar stratosphere where near-space conditions can be attained for 10 to 30 days. The instrument will provide bolometric (wavelength-integrated light) and color temperature images of the Sun. At the upcoming sunspot minimum, SBI observations will be able to detect subtle sources of solar irradiance variation with the least confu...

Parametric modeling of downwelling longwave irradiance under all-sky conditions (LW↓) typically involves “correcting” a clear- (or non-overcast) sky model estimate using solar-irradiance-based proxies cloud cover in lieu actual given uncertainties and measurement challenges the latter. While such approaches are deemed sound, their application time space is inherently limited. We report on corre...

in this study, estimation of global and diffuse solar radiations of selected cities in nigeria was carried out to assess the feasibility of solar energy utilization. the results of this work show the variation of direct and diffuse component of solar radiation in summer and winter months. the contribution of diffuse solar radiation is high during the monsoon months whereas sky conditions are cl...

[1] We present a re-evaluation of the hypothesis of a coupling between galactic cosmic rays, clouds and climate. We have used two independent estimates of low cloud cover from the International Satellite Cloud Climatology Project, covering 16.5 years of data. The cloud cover data are used in conjunction with estimates of galactic cosmic ray flux and measurements of solar irradiance. It is found...

We use Total Solar Irradiance (TSI) measurements from the VIRGO (Variability of solar IRradiance and Gravity Oscillations) instrument on board SOHO to obtain preliminary estimates of the mean total radiative energy emitted by X-class solar flares. The basic tool is that of summed-epoch analysis, which has also enabled us to detect and partially characterize systematic errors present in the basi...

Solar Lyman alpha irradiance is estimat,ed from various solar indices using linear regression analyses. Models developed with ~nultiple linear regression analysis, including daily values and 81-clay running means of solar indices, predict reasonably well both the shortand long-term variations observed in Lyman alpha. It is shown that the full disk equivalent width of tlle He line at 1083 111x1 ...

We measured downwelling spectral vector irradiance (from 350 to 800 nm) during evening civil and nautical twilight (solar elevation down to -12°). Nine sets of measurements were taken to cover the first half of the lunar cycle (from the new to full moon) and were also used to calculate chromaticity (CIE 1976 u'v'). The lunar phase had no consistent effect on downwelling irradiance until solar e...

Imagery from GOES satellites is analyzed to determine how solar variability is related to the NOAA classification of cloud type. Without using a model to convert satellite imagery to average insolation on the ground, this paper investigates using cloud categories to directly model the expected statistical variability of ground irradiance. Hourly cloud classified satellite images are compared to...