Showing papers on "Solar constant published in 1968"
TL;DR: In this paper, the authors developed a method to estimate the shortwave radiation income on different slopes in any latitude can be easily determined from a knowledge of surface geometry and the sun's declination.
Abstract: A formula has been developed whereby variations in the shortwave radiation income on different slopes in any latitude can be easily determined from a knowledge of surface geometry and the sun's declination. This is achieved by expressing slope characteristics and the sun's position as unit vectors in the coordinates of a common system, and multiplying the cosine of the angle between the two vectors by a factor involving the solar constant, atmospheric transmissivity and the optical air mass. Integration of the formula permits the topographic variations of direct shortwave radiation income over specified areas to be calculated for daily or longer periods from radiation observations at a single site. Thus, a device has been developed which has applications in many aspects of pure and applied microclimatology, and which differs from other similar formulae in that it is at the same time both integrable and applicable under different atmospheric transmissivities.
243 citations
TL;DR: In this paper, the solar radiation constant was reevaluated from aircraft instrument observations and ground extrapolations, noting role in spacecraft design and noting the importance of spacecraft design in space exploration.
Abstract: Solar radiation constant reevaluated from aircraft instrument observations and ground extrapolations, noting role in spacecraft design
47 citations
TL;DR: The solar constant was directly measured from an altitude of about 82 kilometers-apparently the first such determination.
Abstract: The solar constant was directly measured from an altitude of about 82 kilometers-apparently the first such determination. The total solar intensity was 136.1 milliwatts per square centimeter, or 1.952 calories per square centimeter, per minute-about 2.5 percent less than Johnson's derived value. Energy in the ultraviolet and visible regions (for lambda less than 607 nanometers) was 7.0 percent less than that obtained by integration over Johnson'Scurve; for integral flux of lambda greater than 607 nanometers there was almost perfect agreement. Seven supporting series of measurements from lower altitudes agreed extremely well with these results after correction for atmospheric extinction.
31 citations
01 Jan 1968
TL;DR: In this paper, a general discussion of the radiation balance of the earth and the influence of changes of extraterrestrial solar radiation on the mean temperature on the earth's mean temperature is presented.
Abstract: The paper opens with a general discussion of the radiation balance of the earth, and of the influence of changes of extraterrestrial solar radiation on the mean temperature of the earth. It is emphasized that the simple black-body radiation model frequently used to relate terrestrial mean temperature changes to solar radiation changes is not necessarily valid. Alternative models, based on information regarding the seasonal variation of the earth’s heat balance, indicate a substantially stronger dependence of temperature on solar radiation than that predicted by the black-body model. The climatological importance of changes in the earth’s orbital elements, given that the heat-storage influence of the oceans acts to suppress seasonal contrasts induced by such changes, is concluded to be inadequate as an explanation of long-term glacial cycles. The role of carbon dioxide fluctuations in climatic change is also considered, and found wanting as a prime cause of glacial cycles.
30 citations
TL;DR: In this paper, the spectral irradiance data from spectroradiometer and photoelectric filter radiometer was used to calculate the solar constant based on spectral irradiances from spectrometers.
Abstract: Solar constant based on spectral irradiance data from spectroradiometer and photoelectric filter radiometer
29 citations
TL;DR: The pattern of reflection of solar radiation from clouds as a function of angle is obtained by statistical analysis of observations from the TIROS IV visible radiation channel (0.55-0.75 μ) as discussed by the authors.
Abstract: The pattern of reflection of solar radiation from clouds as a function of angle is obtained by statistical analysis of observations from the TIROS IV visible radiation channel (0.55–0.75 μ). Readings from the water-vapor window channel (8ndash;12 μ) were used to select cases in which clouds fill the field of view of the sensor. The results show a generally anisotropic reflection pattern, which varies with solar zenith angle. The anisotropy is greatest for large values of solar zenith angle, the main feature in these cases being high intensity values of the radiation reflected at azimuths close to 180° from the sun, and at large zenith angles.
24 citations
TL;DR: In this paper, the authors reviewed instruments and results of Eppley-JPL program using high altitude jet aircraft and rocket research vehicle for solar constant measurement, and showed that the results showed promising results.
24 citations
TL;DR: In this paper, the neutron flux per unit energy induced in atmosphere by solar neutrons computed as function of atmospheric depth compared to cosmic ray induction was compared to solar neutron induction.
Abstract: Neutron flux per unit energy induced in atmosphere by solar neutrons computed as function of atmospheric depth compared to cosmic ray induction
16 citations
01 Jan 1968
TL;DR: In this article, a solar activity-solar modulation theory was proposed to explain atmospheric radiocarbon fluctuations and temperature fluctuations during the Christian era, and it was shown that higher than average sunspot frequency is correlated with higher average annual temperature due to an increase in the solar constant, whereas lower atmospheric C14 concentration is consistent with a lower ======ウスウス¯¯$$ {\bar Q} $$==================\/\/\/\/\/\/▬▬▬▬▬▬▬============
Abstract: Atmospheric radiocarbon fluctuations of ±2.5% and temperature fluctuations of ±0.8C during the Christian era are consistent with a solar activity-solar modulation theory as suggested by Suess. Higher than average sunspot frequency is correlative with higher average annual temperature due to increase in the solar constant, whereas lower atmospheric C14 concentration is consistent with a lower
$$ {\bar Q} $$
due to solar modulation of interplanetary magnetic fields.
12 citations
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
TL;DR: In this article, the spectral distribution from ground level, rocket and satellite observations to obtain value of energy received at top of the atmosphere was used to estimate the energy received from solar electromagnetic radiation spectral distribution.
TL;DR: In this article, the spectral distribution of solar irradiance at the mean Sun-Earth distance and in the absence of the Earth's atmosphere have been compared with similar data published in recent years by six other authors.
TL;DR: In this paper, an attempt was made to separate the true 44-60 A flux from the nominal one measured by the Solrad 8 satellite during 1966, which was the first attempt at separating the two indices of solar activity.
Abstract: An attempt is made to separate the ‘true’ 44–60 A flux from the ‘nominal’ one measured by the Solrad 8 satellite during 1966. The 44–60 A flux recorded at Arcetri through the telemetry of the Solrad 6, 7 and 8 satellites is also examined in order to study its time variations in comparison with other indices of solar activity.
01 Oct 1968
TL;DR: In this paper, solar radiative flux measurements from aircraft, discussing instrumental limitations on precision, were discussed, and the limitations of the precision of the measurements were discussed. But they did not discuss the instrumental limitations of precision.
Abstract: Solar radiative flux measurements from aircraft, discussing instrumental limitations on precision
01 Jan 1968
TL;DR: In this article, solar constant and solar spectral irradiance measurements from high altitude research aircraft, discussing radiation measuring instruments are discussed. But the authors do not discuss the use of these measurements in their experiments.
Abstract: Solar constant and solar spectral irradiance measurements from high altitude research aircraft, discussing radiation measuring instruments