Solar constant

About: Solar constant is a research topic. Over the lifetime, 967 publications have been published within this topic receiving 29647 citations.

Using Earth’s Moon as a Testbed for Quantifying the Effect of the Terrestrial Atmosphere

Abstract: In the past, the planetary radiation balance served to quantify the atmospheric greenhouse effect by the difference between the globally averaged near-surface temperature of and the respective effective radiation temperature of the Earth without atmosphere of resulting in . Since such a “thought experiment” prohibits any rigorous assessment of its results, this study considered the Moon as a testbed for the Earth in the absence of its atmosphere. Since the angular velocity of Moon’s rotation is 27.4 times slower than that of the Earth, the forcing method, the force-restore method, and a multilayer-force-restore method, used in climate modeling during the past four decades, were alternatively applied to address the influence of the angular velocity in determining the Moon’s globally averaged skin (or slab) temperature, . The multilayer-force-restore method always provides the highest values for , followed by the force-restore method and the forcing method, but the differences are marginal. Assuming a solar albedo of , a relative emissivity , and a solar constant of and applying the multilayer-force-restore method yielded and for the Moon. Using the same values for α, e, and S, but assuming the Earth’s angular velocity for the Moon yielded and quantifying the effect of the terrestrial atmosphere by . A sensitivity study for a solar albedo of commonly assumed for the Earth in the absence of its atmosphere yielded , , and . This means that the atmospheric effect would be more than twice as large as the aforementioned difference of 33 K. To generalize the findings, twelve synodic months (i.e., 354 Earth days) and 365 Earth days, where , a Sun-zenith-distance dependent solar albedo, and the variation of the solar radiation in dependence of the actual orbit position and the tilt angle of the corresponding rotation axis to the ecliptic were considered. The case of Moon’s true angular velocity yielded and . Whereas Earth’s 27.4 times higher angular velocity yielded , and . In both cases, the effective radiation temperature is , because the computed global albedo is . Thus, the effective radiation temperature yields flawed results when used for quantifying the atmospheric greenhouse effect.

Einstein’s Equation in Nuclear and Solar Energy

Abstract: Starting from the equation of Einstein (E = m·c2), the chapter proposes a simple and fundamental presentation of the fission and fusion principles, together with some of their applications: nuclear reactors and nuclear propulsion vessels and submarines. Fission and fusion are chosen between the multiple forms of energy, as being the most important forms of nuclear energy, directly related with the equation of Einstein. Some characteristics of solar energy, produced from the fusion process inside the Sun, are deducted from the same equation of Einstein: thermal power of solar radiation; specific power of solar radiation; surface temperature of the Sun; solar constant on different planets, etc. The yearly variation of the solar radiation on each planet of the solar system is also presented.

Variations of the solar activity and irradiance, and their influence on the flooding of the river Nile

Abstract: Autocorrelation and power spectra analysis are carried out for different lengths of time series Of the following data:(l) Solar activity (sunspot, faculae and radio flux on 2800 MHz);(2) Irradiance (solar Constant measured at earth's surface and by the artificial satellite (Nimbus- 7); (3) River Nile flood (old water level, maximum flood level, and the difference between the both levels) measured at Cairo. The results showing remarkable similarity between the power spectra of solar activity, irradiance (solar constant) and river Nile flood. We conclude that any short or long-term variations in the solar activity lead to similar variations in the solar constant. Also, annual and secular variations of solar activity yield information’s on the suspected annual and secular variations of the river Nile flood.

Calibration Device Development for Spherical Solar Radiation Sensors

Abstract: Measuring the solar radiation received by a plant canopy is necessary to analyze its physiological aspects. A spherical photodiode has been developed for this purpose. However, a horizontally set calibrated solarimeter using a flat type sensor cannot be used for calibration because it must remain unaffected by the cosine law. Therefore, an inexpensive automatic tracking solar disk system has been developed for the calibration of a spherical type solarimeter. A calibrated solarimeter was mounted on the tracking system and was inclined according to the altitude and the declination angle of the location on the day of the experiment. The system calibrated all four spherical solarimeters with high correlation coefficients . Some data exceed the so-called solar constant, which is measured similarly, but outside of the earth atmospheric layer because the device developed this time measured hemispherical solar radiation normal to the sun disk. Similar data were reported even from horizontal measurements.