Showing papers on "Solar constant published in 2008"
TL;DR: In this article, a fully coupled ocean-atmosphere general circulation model (FOAM) with an 11-year-period cosine signal of amplitude ∼2.0 W m−2 to the solar constant in the model was presented.
Abstract: [1] The quasidecadal oscillation (QDO) of 9- to 13-year period in the Earth's climate system has been found governed by a delayed action oscillator (DAO) mechanism in the tropical Pacific Ocean similar to that governing the El Nino–Southern Oscillation (ENSO) of 3- to 5-year period. It also fluctuated in phase with the ∼11-year-period signal in the Sun's total irradiance throughout the twentieth century. In earlier attempts to explain this association, a conceptual ocean-atmosphere coupled model of the DAO mechanism in the tropical Pacific Basin was driven by 11-year-period solar forcing, producing a QDO that was in damped resonance with the solar forcing. In the present study, we likewise force a fully coupled ocean-atmosphere general circulation model (i.e., Fast Ocean-Atmosphere Model (FOAM)) of Jacob et al. (2001), adding an 11-year-period cosine signal of amplitude ∼2.0 W m−2 to the solar constant in the model. In the presence of this 11-year-period solar forcing the FOAM simulates both the ENSO and the QDO, while in its absence the FOAM simulates only the ENSO. We find the model QDO governed by a tropical DAO mechanism with patterns and evolution similar to those observed. We find its warm phase lagging peak solar forcing by ∼1–3 years, as observed and consistent with damped-resonant excitation of the tropical DAO of the QDO by the 11-year-period solar forcing in the earlier conceptual model.
65 citations
Posted Content•
TL;DR: In this paper, the authors show that the effect of a changing Newtonian gravity constant is negligible and that the value of AUmet can be made constant by redefining it, based on a reference solar mass unit, such as the solar mass at J2000; else, the solar Gaussian gravity constant kGS used in defining the AU could be redefined proportional to the square root of the solar masses.
Abstract: The radiative and particulate loss of mass by the Sun, -9.13*10^-14 Solar masses per year or more causes the orbits of the planets to expand at the same rate, and their periods to lengthen at twice this rate. Unfortunately, under the present definition of the Astronomical Unit (AU) based on the fixed Gaussian gravity constant kGS = 0.01720209895 (AU)^1.5/day, the value AUmet of the AU in meters must decrease at 1/3 this rate, all these rates being expressed logarithmically. The progress of the planets along their orbits slows quadratically with time. For example, in one century Mercury would lag behind the position predicted using constant solar mass by almost 1.4 km, in two centuries 5.5 km. The value of AUmet can be made constant by redefining it, based on a reference solar mass unit, such as the solar mass at J2000; else, the solar Gaussian gravity constant kGS used in defining the AU could be redefined proportional to the square root of the solar mass. Improved accuracy of the ephemerides would impose useful bounds on losses due to axion emission (Sikivie 2005). With no axion emission the Earth's semi-major axis grows 1.37 m/cy; with the maximum allowable such emission the result is 1.57 m/cy. Under reasonable assumptions about alternate gravity theories, radar delay data are used to show that the effect of a changing Newtonian gravity constant is negligible.
35 citations
TL;DR: In this article, a peak-to-peak variation in the geocentric north-south solar radius of 0.136 ± 0.01, approximately in phase with the solar cycle was observed.
Abstract: Full-disk photometric solar images at a wavelength of 672.3 nm have been obtained daily since 1986 using the CFDT1 (Cartesian Full Disk Telescope No. 1). An analysis of these images from 1986 through the end of 2004 December has shown a peak-to-peak variation in the geocentric north-south solar radius of 0.136 ± 0.01, approximately in phase with the solar cycle. The multiple correlation coefficient squared is R2 = 0.0404 (R = 0.2). While this correlation coefficient is small, due to the large number of data points (N = 4042), the level of significance is less than 0.02. The radius had a maximum value near the times of maximum activity for solar cycles 22 and 23.
23 citations
Journal Article•
TL;DR: In this article, a semi-spherical solar collector with the absorber in the shape of a semi sphere was constructed and theoretical calculations of received energy which have been carried out, based on continual visible position of the sun in the sky.
Abstract: Solar energy is widely used as an environmentally friendly energy source in many countries, Latvia among them. However, geographical and climatic conditions in Latvia, low maximal height of the sun and maximal irradiance, as well as comparatively great cloudiness, present particular challenges. Long days and the long path of the sun in summertime means traditional constructions of solar collectors are not efficient enough for use in Latvia. A new principle in the construction of the solar collector has been developed: a solar collector with the absorber in the shape of a semi-sphere. It has advantages in comparison with the traditional fixed flat-plate model: it effectively receives both direct and diffuse solar radiation all day. In addition, it is durable against the destructive impact of the wind. This article reports theoretical calculations of received energy which have been carried out, based on continual visible position of the sun in the sky. Results of these calculations have shown that on a clear sunny day, a semi-spherical collector with the base of 1 m 2 receives 1.3 times more energy than a flat-plate collector positioned at optimal (approx. 40 o ) inclination, and 1.6 times more than the flat horizontal one. In cloudy conditions, the difference is greater because of greater diffused radiation. Such a semi-spherical solar collector has been constructed. Experimental investigation of the received heat energy from the semi-spherical solar collector will be carried out in field conditions this summer.
17 citations
TL;DR: The Flare Irradiance Spectral Model (FISM) as mentioned in this paper is an empirical model that estimates the solar irradiance at wavelengths from 0.1 to 190nm at 1-nm resolution with a time cadence of 60 s. This model also captures variations on the longer time scales of solar rotation (days) and solar cycle (years).
12 citations
01 Jan 2008
TL;DR: In this paper, the authors revisited Pouillet's work with current knowledge and found that Poulet's results are quite robust. But they also evaluated the total absorption of solar radiation by the atmosphere.
Abstract: Claude Pouillet greatly contributed to the development of climate sciences by estimating the solar constant, i.e. the incoming solar radiation at the top of the atmosphere (also called total solar irradiance). The value obtained by Pouillet is only 10% lower than modern estimates, but Pouillet's contribution is sometimes omitted or underestimated. He also evaluated the total absorption of solar radiation by the atmosphere. The aim of this paper is to revisit Pouillet's work with our current knowledge. It appears that Pouillet's results are quite robust.
8 citations
Proceedings Article•
01 Oct 2008
TL;DR: In this article, a curved surface renewable solar cell is applied to provide a near space airshippsilas energy system the power to drive the high altitude electromotor and propeller in a long term.
Abstract: Curved surface renewable solar cell is applied to provide a near space airshippsilas energy system the power to drive the high altitude electromotor and propeller in a long term. The solar flux incident on the solar cell is calculated through integral transform and some revised correlations from tilted surface solar radiation flux calculations. In view of the solar radiation flux and the wind speed fluctuation and randomicity, wavelet analysis and genetic algorithm aided neural networks are combined to make the solar radiation flux predictable and real-time with higher precision than solar constant radiation spatial interpolation.
6 citations
Journal Article•
TL;DR: In this paper, the authors constructed a real-time model of the relationship between solar irradiance and solar constant, solar radiation incidence angle and the Sun-Moon distance, and validated the possibility of existing polar day and polar night at the lunar poles.
Abstract: Information about solar irradiance on the lunar surface is the key to understanding lunar-surface temperature distribution. In this study, we have constructed a lunar-surface effective solar irradiance real-time model in terms of the relationship between solar irradiance and solar constant, solar radiation incidence angle and the Sun-Moon distance. The theoretical erroneous percentage of this model is less than 0.28% during 100 years from 1950 to 2050. These indicate that the model can accurately reflect the variation of effective solar irradiance on the lunar surface. The result showed that the total solar irradiance on the lunar surface would change from 1321.5 to 1416.6 W·m~ -2 in 2007. And the average is 1368.0 W·m~ -2 . We also validated the possibility of existing polar day and polar night at the lunar poles by analyzing the result of solar radiation incidence angle.
4 citations
01 Jan 2008
TL;DR: In this paper, the authors discuss the global radiation balance and its main components, including solar radiation and its spectrum, and its role in the functioning of all ecosystems, including the Earth's surface and atmosphere.
Abstract: Global radiation balance ultimately controls the climate of the Earth and thus plays an important role in the functioning of all ecosystems. The two key components of the global radiation balance are solar radiation, which is emitted by the Sun, and terrestrial radiation, which is emitted by the Earth’s surface and atmosphere. Besides regulating climate, solar radiation is vital for sustaining life on our planet, given that almost all living organisms need sunlight for their well-being. This article discusses the global radiation balance and its main components, including solar radiation and its spectrum.
4 citations
04 Jan 2008
TL;DR: In this paper, Baily beads observed in total eclipse of March 29, 2006 (Egypt) and those of annular eclipses of September 22, 2006 and October 3, 2005 (Spain) are used to evaluate the variations of solar radius with respect to its standard value during a whole draconitic year.
Abstract: Data on Baily beads observed in total eclipse of March 29, 2006 (Egypt) and those of annular eclipses of September 22, 2006 (French Guyana) and October 3, 2005 (Spain) are used to evaluate the variations of solar radius with respect to its standard value during a whole draconitic year. A portable observatory has to be set on the shadow limit of central eclipses, where lunar limb is grazing to the solar one and the number of beads is large. The observation of solar corona during Egyptian eclipse for several minutes during maximum eclipse on shadow's limits is studied in parallel with the eclipse observed by Clavius in 1567. From fall 2005 to fall 2006 the solar radius does not show significant changes (0.00 to −0.01 arcsecs) with respect to its standard value of 959.63 arcsec within errorbars of 0.17 arcsecs. This is its value at minimum of cycle 23 of solar activity.
3 citations
TL;DR: In this paper, the authors discuss the education of astronomy and space science in Egypt at the university level since 1936 at the Department of Astronomy and Meteorology of Cairo University, and the total solar eclipse observations on 25th February, 1952 in Khartoum have been done by on Egyptian-French group by using the Worthington Camera.
Journal Article•
TL;DR: In this paper, solar radiation and meteorological parameters were measured at the north slope of the Mount Qomolangma during 27 May to 30 June 2006, and the measured parameters are solar global radiation,reflective radiation,atmospheric radiation,terrestrial radiation,net radiation,temperature,humidity and wind.
Abstract: Solar radiation and meteorological parameters were measured at the north slope of the Mount Qomolangma during 27 May to 30 June 2006.The measured parameters are solar global radiation,reflective radiation,atmospheric radiation,terrestrial radiation,net radiation,temperature,humidity and wind.All radiative and meteorological parameters displayed evident and asymmetric diurnal variations.Solar radiation at the north slope of the Mount Qomolangma was much higher than the plain region,and the phenomena of solar global radiation exceeded solar constant were often occurred.The study showed that all radiative parameters exhibited a daily maximum of increasing rate at 0900 LST.And it caused the increase of air temperature and the fast increase of wind speed from then on.So,the specific topography at the north slope of the Mount Qomolangma led to evident effects on solar radiations arriving at the ground,air temperature and air-mass moving by different radiation processes.It is very important to study the characteristics of solar radiation,the interaction between radiation,earth's surface and the atmosphere,the response of the earth and the atmosphere to solar radiation at the specific topography.It will help us to understand the exchanging process of mater and energy deeply and thoroughly.
16 Jun 2008
TL;DR: The role of the solar constant (S) in driving surface temperature has been investigated in this paper, showing that on time scales of days to years, known fluctuations in S can perturb surface temperature by at most a few tenths of a degree C.
Abstract: Recent measurements of changes of 0.1‐0.3% in the solar constant (S) made from the SMM and Nimbus spacecraft clarify the possible role of the solar constant in driving surface temperature. On time scales of days to years, known fluctuations in S can perturb surface temperature by at most a few tenths of a degree C. Alhough they have been hypothesized, there is as yet no direct, observational evidence for longer‐term, secular changes in S that could be a stronger force in climate.
TL;DR: In this article, the authors determined the minimums of the 11-year solar cycles based on a minimal flux of the large-scale open solar magnetic field, and the long-term tendency toward an approach to a deep minimum of solar activity is confirmed.
Abstract: It is proposed to determined minimums of the 11-year solar cycles based on a minimal flux of the large-scale open solar magnetic field. The minimal fluxes before the finished cycle 23 (Carrington rotation CR 1904) and the started cycle 24 (CR 2054, April 2007) were equal to 1.8 × 1022 and 1.2 × 1022 μs, respectively. The long-term tendency toward an approach to a deep minimum of solar activity is confirmed. On the assumption that magnetic flux variations from minimums to maximums are proportional to each other, the anticipated value of the maximal Wolf number during cycle 24 is estimated as Wmax = 80.