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Solar constant

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


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Journal ArticleDOI
TL;DR: The cavity pyrheliometer sensor aboard Nimbus 7 is now in its tenth year of operation and results for 9 1/2 years show a decreasing trend through the end of solar cycle 21 of approximately -0.015 percent per year, a leveling off near solar minimum and an increasing irradiance for the beginning of cycle 22.

11 citations

01 Jan 1975
TL;DR: In this paper, the solar irradiance was derived from a number of sources and an attempt was made to bring these data onto a uniform scale, yielding a figure of 1357.826 for the solar constant.
Abstract: Data are presented on the solar irradiance as derived from a number of sources. An attempt was made to bring these data onto a uniform scale. Summation of fluxes at all wavelengths yields a figure of 1357.826 for the solar constant. Estimates are made of the solar flux variations due to flares, active regions (slowly varying component), 27-day period, and the 11-yr cycle. Solar activity does not produce a significant variation in the value of the solar constant. Variations in the X-ray and EUV portions of the solar flux may be several orders of magnitude during solar activity, especially at times of major flares. It is established that these short wavelength flux enhancements cause significant changes in the terrestrial ionosphere.

11 citations

Journal ArticleDOI
TL;DR: In this article, a method for improving low-Earth-orbiting satellite operations and space surveillance tracking has been developed using the SOLAR2000 empirical solar irradiance model, which provides high time resolution, nowcast, and forecast solar irradiances including the E 1 0. 7 proxy.
Abstract: Low-Earth-orbit satellite operators often require accurate and precise knowledge of their spacecraft location and attitude for the recent past, the present, and the near future. The same is true of space surveillance operators tracking space debris with low perigee orbits. Unwanted orbital and attitude orientation changes occur as a result of drag and perturbations that are related to atmospheric density changes. These changes are primarily induced by solar extreme ultraviolet irradiance variations and geomagnetic storms, that is, one of the effects of space weather. A method for improving low-Earth-orbiting satellite operations and space surveillance tracking has been developed using the SOLAR2000 empirical solar irradiance model. SOLAR2000 is an operational grade solar irradiance specification model that provides high time resolution, nowcast, and forecast solar irradiances including the E 1 0 . 7 proxy. E 1 0 . 7 is a replacement for 10.7-cm solar radio flux F 1 0 . 7 in atmospheric density models that are linked with orbit determination algorithms. Recent previous validation work shows the improvement of using daily E 1 0 . 7 vs F 1 0 . 7 for satellite orbit determination. The operational application and use of the E 1 0 . 7 proxy are described in this work.

11 citations

Journal ArticleDOI
30 Aug 2016
TL;DR: In this paper, the authors analyzed seasonal and spatial variation of solar radiation and shed some light on solar energy potential and prospect of vegetation development in the mountainous region of Nepal, showing significant similarities and differences on solar radiation with respect to seasons and locations.
Abstract: Solar radiation data (two-hourly data from 1987 to 1999) observed at high altitude meteorological stations in Nepal Himalayas were analyzed to study seasonal and spatial variation of solar radiation and shed some light on solar energy potential and prospect of vegetation development in the mountainous region of Nepal. Results showed significant similarities and differences on solar radiation with respect to seasons and locations (altitudes). Mean seasonal amount of solar radiation was generally higher in spring than in summer. The significant amount of monsoonal clouds in the summer hindered incoming solar radiation during summer, while less or no clouds during spring allowed more solar radiation to reach the earth’s surface. Absolute extreme values of solar radiation in the mountainous regions during fine weather conditions were close to the solar constant (1367 Wm -2 ) due to negligible depletion of radiation within the atmosphere. Amount of solar radiation increased with altitude due to smaller optical depth of the atmosphere at higher altitudes. The increasing rate of annual mean solar radiation with altitude is found to be 90 Wm -2 km -1 in the mountainous region of Nepal. Journal of Hydrology and Meteorology, Vol. 8(1) p.1-9

11 citations

Journal ArticleDOI
01 Jul 1968
TL;DR: In this article, the influence of various cloud types on solar radiation at sea was determined based on observations taken aboard the R V "Alaminos" in the Gulf of Mexico, Caribbean Sea, and western sub-tropical Atlantic Ocean, June 1965.
Abstract: Determinations were made of the influence of various cloud types on solar radiation at sea Computations were based on observations taken aboard the R V “Alaminos” in the Gulf of Mexico, Caribbean Sea, and western sub-tropical Atlantic Ocean, June 1965 Only partly cloudy conditions were considered Modifications due to clouds produced both decreases and increases in insolation values Decreases, primarily related to reduction of the direct beam by obscuration, averaged 18 percent with cirrus clouds and 85 percent with cumulonimbus clouds; associated maximum values were 26 percent and 97 percent, respectively Increases of insolation, related to enhancement of the diffuse component due to reflection and multiple scattering, averaged 4 percent with the cirrus and 12 percent with cumulonimbus clouds; associated maximum increases were 8 percent and 38 percent, respectively Such increases, although of short duration, may give insolation values in excess of that of the “solar constant,” ie, 200 ly/min

11 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20238
202215
20219
20202
201911
201810