Showing papers on "Solar constant published in 1970"

Transformation of the absolute solar radiation data into the ‘International Practical Temperature Scale of 1968’

Abstract: Corrections are given which transform the Tables of the solar radiation data (Labs and Neckel, 1968) into the ‘International Practical Temperature Scale of 1968’. Additionally, for the adjustment of the data of the ‘true continuum’ and the corresponding line blanketing as well, the veiled line effect mentioned first by Carbon et al. (1968), but studied in more detail by Holweger (1970a), has been considered also. The corresponding corrections of the solar irradiance result in an improved value of the spectrophotometric solar constant: S = 1.947 cal cm-2 min-1 or 0.1358 W cm-2. Two Tables presenting the ‘highest (window-) intensities’ and the corrected irradiance data have been added.

Solar radiation and solar activity

Abstract: Using high-altitude balloon soundings (1961 to 1968) and other data, it is shown that the most reliable maximum value of the solar constant is at present 1.94 cal cm−2 min−1, to an accuracy of 1 per cent. This value is observed with Wolf numbers between 80 and 100, below or above which the solar constant decreases. The maximum decrease does not exceed 2 to 2.5 per cent. The observations reveal the influence of nuclear explosions and volcanic eruptions which caused an anomalous turbidity of the upper atmospheric layers. These anomalies have been studied. The above conclusions require further confirmation using direct long-term measurements of the solar constant outside the atmosphere.

Apparent solar constant variations and their relation to the variability of atmospheric transmission

Abstract: The considerations contained in the following article are all based on the large number of observations of sun radiation and atmospheric transmission collected by the Astro-physical Observatory of the Smithsonian Institution. The author has shown that there is a close correlation between the variability of transmission and the apparent variability of the solar constant as it is presented in the Volumes of the Astrophysical Observatory. The relationship is explained on the basis of theoretical deductions presented by Dr R. Lundblad (1922) and by the present author (1921) at an early date. Further results, concerning the connection between the spectral distribution of intensity of the apparent solar constant and the variations of transmission, are based on the named theory. If the variability of the apparent solar constant is reduced to a value corresponding to a constant transmission, the remaining variability seems to coincide very closely with the standard error which can be expected in radiation measurements with our most accurate pyrheliometers. A short preliminary note is added concerning the wavelength dependence of atmospheric scattering as derived from the variability of the transmission for different wavelength intervals where no selective absorption occurs. DOI: 10.1111/j.2153-3490.1970.tb01522.x

The energy balance climatology of a city‐man system

Abstract: The urban energy balance climatology of the city and man in the Los Angeles basin was examined during a cloudy day (“Catalina eddy”) in September, 1968, from about sunrise to sunset, by measuring or estimating solar radiation, net radiation, ground heat flux, actual surface temperature, terrain radiant temperature, radiant sky temperature, and dry and wet-bulb temperature for the physical urban interface. An analogous theoretical model attempted to define the input of energy to the human interface via the solar heat load, and the disposal of human net radiation was shown via the channels of latent, sensible, and body heat flux. In spite of an apparent uniform cloud cover, the energy parameters had considerable areal variation in intensity and trend. During the daylight hours seventy percent of the solar radiation was absorbed. An additional thirty-two percent was removed by longwave radiation. Of the net radiation received on the dry surface (forty-seven percent of solar radiation), about eighty percent was disposed via sensible heat flux, and the remainder entered the pavement as storage. Air temperatures taken at shelter height were out of phase with the ongoing energy regime and were deemed of dubious value in urban climatic studies. Urban man received only thirty-seven percent and seventy percent of the values available at the horizontal pavement for solar radiation and net radiation, respectively. A series of empirical and theoretical models show high correlations with the observations. It appeared that solar radiation and net radiation (physical and human) could have been estimated via the solar constant and appropriate transmissivities.

9. On Determinations of the Atmospheric Turbidity and their Relation to Pyrheliometric Measurements

Abstract: Publisher Summary This chapter discusses the process of scattering of solar radiation within the atmosphere The question concerning the transmission of solar radiation through the atmosphere cannot be adequately treated without considering the radiation from the source itself—that is, from the sun The sun sends out a whole spectrum of wavelengths that also gives a schematic idea of how this radiation is influenced, for different wavelengths, through extinction in the atmosphere The integral of the solar radiation over all wavelengths, reduced to the mean distance between the earth and the sun, is generally denoted the solar constant The scattering of solar radiation within the atmosphere has a double cause—namely, (1) scattering by the air molecules, and (2) scattering and absorption by solid and liquid particles within the atmosphere The existence of such a molecular scattering was first pointed out and investigated on a theoretical basis by Lord Rayleigh With slight supplements to his theory, especially regarding the so-called depolarization effect of unsymmetrical molecules, it can be stated that observations in very clear air, in the Antarctic, and on high mountains show close agreement with the theory The Rayleigh scattering, as it is often called, is inversely proportional to the fourth power of the wavelength On the other hand, the scattering by the liquid and solid particles of the atmosphere—by what is usually termed “aerosol”—is highly dependent on the purity of the atmosphere, that is, on the number, sizes, and qualities of the scattering particles

A one-solar-constant irradiance standard.

Abstract: A new high-intensity standard of total and spectral irradiance has been developed recently at the National Bureau of Standards. The standard consists of a 1000-W tungsten–halogen lamp mounted in a ceramic reflector, the reflecting surface of which is coated with flame-sprayed Al2O3. The lamp–reflector combination results in a source having a relatively small (3 cm × 5 cm) radiating area yielding a total irradiance, at a distance of 40 cm, of about 136 mW cm−2. The total irradiance calibrations are based on the radiance of a 1400-K blackbody and have an estimated maximum systematic error of 0.9% and a maximum estimated standard error of 0.19%. The spectral measurements were made over the wavelength range of 0.3 μm to 2.5 μm relative to the NBS 1000-W tungsten–halogen irradiance standards. The estimated uncertainty in these measurements ranges from 4% in the visible and near ir to 8% in the uv.

Surface temperature of the early Earth and the nature of the terrestrial atmosphere.

Abstract: THE detailed models of solar evolution now available clearly indicate that the luminosity of the Sun has been gradually increasing since it first arrived on the main sequence some 5 × 109 yr ago. If it is assumed that any changes in the orbit of the Earth during this time have been periodic—so that the present orbit is very nearly the average orbit—then it follows that the value of the solar constant has also increased correspondingly. The possibility of a resultant variation in the surface temperatures of the planets is of particular interest for the Earth, which is the only planet at present possessing a considerable quantity of water in the liquid state on its surface.

Proposed new engineering standard for the solar constant and zero air mass solar spectral irradiance

Abstract: Engineering standard for solar constant and zero air mass solar spectral irradiance from high altitude measurements