scispace - formally typeset
Search or ask a question
Topic

Solar constant

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


Papers
More filters
01 Aug 1982
TL;DR: In this article, the authors described the radiometric methodology in use with a narrow field of view radiometer for observation of the solar constant, where the radiation output of the Sun is assumed to be constant, enabling the monitoring of the sun source by an accurately pointed radiometer, and the Sun's output is measured as a function of time.
Abstract: The radiometric methodology in use with a narrow field of view radiometer for observation of the solar constant is described. The radiation output of the Sun is assumed to be constant, enabling the monitoring of the solar source by an accurately pointed radiometer, and the Sun's output is measured as a function of time. The instrument is described, its angular response considered, and principles for absolute radiometric measurement presented. Active modes of operation are analyzed, taking into consideration instrumental perturbations and sensor efficiency, heating wire effect, cavity sensor efficiency, thermal effects on the surface of the sensitive area, the effect of the field of view limiting system, and the frequency response of the heat flux detector and absolute radiometric system. Performance of absolute measurements with relatively high accuracy is demonstrated.

2 citations

01 May 1974
TL;DR: In this article, the relationship observed between enhancements in the far ultraviolet solar irradiance and the position of the solar magnetic sector boundaries is described, at least during the year of 1969, that the ultraviolet maxima tend to occur near the times when a solar sector boundary is near the central meridian.
Abstract: A description is given of the relationship observed between enhancements in the far ultraviolet solar irradiance and the position of the solar magnetic sector boundaries. The ultraviolet observations were made with the monitor of ultraviolet solar energy (MUSE) experiments which were launched aboard Nimbus 3 in April 1969 and Nimbus 4 April 1970. A comparison between the positions of solar magnetic sector boundaries and ultraviolet enchancements of the sun seems to show, at least during the year of 1969, that the ultraviolet maxima tend to occur near the times when a solar sector boundary is near the central meridian. An estimate of the magnitude of the variable ultraviolet solar energy input into the atmosphere resulting from the rotation of active solar longitudes is that for wavelengths less that 175 nm and down to H Lyman alpha it exceeds the annual variation whereas at longer wavelengths it is less. The total observed peak to peak variation in the ultraviolet irradiance from 120 to 300 nm over a solar rotation is typically at least 230 ergs/sq cm sec.

2 citations

Journal ArticleDOI
TL;DR: In this paper , a semi-empirical total solar irradiance (TSI) model was used to reconstruct solar luminosity over the entire 4π solid angle around the Sun, which was constrained by comparing its output to the irradiance in the Earth's direction with the measured TSI.
Abstract: Luminosity, which is the total amount of radiant energy emitted by an object, is one of the most critical quantities in astrophysics for characterizing stars. Equally important is the temporal evolution of a star’s luminosity because of its intimate connection with the stellar energy budget, large-scale convective motion, and heat storage in the stellar interior. The Sun’s luminosity and its variation have not been measured to date because current observations of the solar radiative output have been restricted to vantage points near the Earth. Here, we model the solar luminosity by extending a semiempirical total solar irradiance (TSI) model that uses solar-surface magnetism to reconstruct solar irradiance over the entire 4π solid angle around the Sun. This model was constrained by comparing its output to the irradiance in the Earth’s direction with the measured TSI. Comparing the solar luminosity to the TSI on timescales from days to solar cycles for cycles 23 and 24, we find poor agreement on short timescales (

2 citations

Journal ArticleDOI
TL;DR: In this paper, the maximum percent of color in the total direct solar radiation during the true eclipse from the first contact to the end contact was in the infrared, where the percent were in the green (11.74%), yellow (15.69%), red (14.88%), and infrared (57.68%).
Abstract: Problem statement: Measurement of the different components of solar radiation and fractions of these components for the global (horizontal and tracker), direct (white and three colors, yellow, red and infrared) and diffuse solar radiation during the solar eclipse, 29 March 2006 at Tobruq, Libya (Lat. 32.08°N and Long. 23.98°E). The time interval of solar eclipse was 2 h: 40 m and the maximum magnitude of eclipse at this region was 0.995. Conclusion: The results showed that the maximum percent of color in the total direct solar radiation during the true eclipse from the first contact to the end contact was in the infrared, where the percent were in the green (11.74%), yellow (15.69%), red (14.88%) and infrared (57.68%).

2 citations

Proceedings ArticleDOI
27 Sep 2012
TL;DR: In this article, a novel design of the sun tracker has been tested and is able to do two-axis tracking for photovoltaic based solar electricity generating system (SEGS).
Abstract: The volatile fossil fuel price currently creates an opportunity for the development of alternative approaches in electricity generation. Comprehensive and concerted efforts are focused at developing solar electricity generating system (SEGS). One of the challenges faced by SEGS is the apparent trajectory of the sun. Often, SEGS designers use standard testing conditions, whereby the level of solar insolation is taken to be a constant value of 1000W/m2. The only value of solar insolation that is taken to be constant is known as solar constant, which is approximately 1353W/m2. Solar constant is the solar insolation received outside the earth's atmosphere. This value drops significantly as the solar radiation passes through the atmosphere, where the typical range is between 150 W/m2 and 1000W/m2. The reducing intensity of solar insolation is also due to the apparent trajectory of the sun. The sun's path changes daily, and in this project, a novel design of the sun tracker has been tested and is able to do two-axis tracking for photovoltaic based SEGS.

2 citations


Network Information
Related Topics (5)
Convection
39.6K papers, 916.8K citations
79% related
Climate model
22.2K papers, 1.1M citations
79% related
Sea surface temperature
21.2K papers, 874.7K citations
78% related
Radiative transfer
43.2K papers, 1.1M citations
76% related
Ice sheet
16.6K papers, 781.2K citations
73% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20238
202215
20219
20202
201911
201810