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Showing papers on "Solar constant published in 1979"


Journal ArticleDOI
22 Feb 1979-Nature
TL;DR: In this article, it was shown that CO2-H2O in a weakly reducing atmosphere could have caused a change in the early Earth's temperature by the so-called greenhouse effect.
Abstract: CURRENT models for the evolution of the Sun require an increase in solar luminosity by 25% since the formation of the Solar System1. Such an increase in the solar constant should have profound effects on the terrestrial climate, but there is no evidence from the fossil record of a corresponding change in the Earth's global mean temperature2. This apparent conflict cannot be explained by the apparent inability of solar models to account for the low observed neutrino flux3. Even models that are forced to fit the neutrino data require a similar increase in the solar luminosity. As Newman and Rood1 state: “a faint young Sun is one of the most unavoidable consequences of stellar structure considerations”. We discuss here whether CO2–H2O in a weakly reducing atmosphere could have caused this change in the early Earth's temperature by the so-called greenhouse effect.

273 citations


Journal ArticleDOI
TL;DR: A new cavity pyrheliometer, the active cavity radiometer type IV (ACR IV), has been developed for the measurement of total solar optical irradiance, and analysis predicts its ability to measure at the solar constant level with 0.1% uncertainty in SI units.
Abstract: A new cavity pyrheliometer, the active cavity radiometer type IV (ACR IV), has been developed for the measurement of total solar optical irradiance Analysis predicts its ability to measure at the solar constant level with 01% uncertainty in SI units In comparison tests ACR IVs have consistently demonstrated 03% higher results than the World Radiometric Reference scale A prototype has been tested, and a flight instrument has been developed and flown in a sounding rocket experiment to determine the solar constant ACR IV instrumentation is being developed for flight experiments on the Spacelab I and Solar Maximum missions to monitor the total solar output of optical radiation as part of a long-term program to detect variations of climatological significance

108 citations


Journal ArticleDOI
21 Dec 1979-Science
TL;DR: Forcing with volcanic dust produces the best simulation, whereas expressing the solar constant as a function of the envelope of the sunspot number gives very poor results.
Abstract: Numerical energy balance climate model calculations of the average surface temperature of the Northern Hemisphere for the past 400 years are compared with a new reconstruction of the past climate. Forcing with volcanic dust produces the best simulation, whereas expressing the solar constant as a function of the envelope of the sunspot number gives very poor results.

97 citations


Journal ArticleDOI
TL;DR: In this paper, the seasonally effective thermal inertia (SEI) is used to simulate the seasonal cycle of surface air temperature and meridional heat transport in a completely zonally averaged model.
Abstract: The mean annual energy balance climate model of Gal-Chen and Schneider (1976) is expanded to a more general model which includes an interactive lower layer. The two-layer model is used to simulate the seasonal cycle through the use of seasonally varying insolation. Rather than greatly modifying the zonal model parameterizations, we choose to determine the extent to which the use of the present parameterizations in a completely zonally averaged model can reasonably simulate the seasonal cycle of surface air temperature and meridional heat transport. It is found that the model-derived cycle of surface air temperature lags the observations by 1–2 months, but the amplitude of the seasonal cycle can be well simulated by using reasonable annual mean values of the seasonally effective zonal thermal inertia. The seasonal variations in the meridional transport of energy by the atmosphere agree qualitatively in mid-latitudes with the data of Oort (1971), but they suffer from large errors in the tropics. Seasonal simulation indicates that the diffusive atmospheric energy transport parameterization based on annual data is inappropriate in this region. Comparisons of annual and seasonal models show that there is little difference in temperature sensitivity for solar constant changes. Unlike previous low-resolution climate models the seasonally effective thermal inertia is also allowed to vary with time to simulate the seasonal variation of the oceanic mixed layer depth. This modification requires the addition of a second lower vertical layer in the model, the temperature of which is predicted explicitly. Such seasonal thermal inertia variations have little effect on the model's equilibrium response to solar constant changes. Experiments employing step function and exponential solar constant increases show the time-dependent response of global surface temperature to lag the solar constant perturbation by from a few years to a few decades, depending on the assumptions of seasonal thermal inertia variation and lower layer thickness. The uncertainty in the range of global temperature lag time implies that modeling the time-dependent temperature response to a CO2 perturbation will require refined treatment of the coupling between upper and lower oceanic heat reservoirs. The most important general conclusion from these experiments is that realistic values of seasonally effective thermal inertia (i.e., primarily the oceanic mixed layer depth) are needed for the realistic simulation of the seasonal cycle of temperature. Use of realistic seasonal thermal inertia implies that climate sensitivity experiments with seasonal models (including global circulation models) will require decades of model simulation time to approach a reasonable climatic equilibrium.

81 citations


Journal ArticleDOI
TL;DR: In this article, the same data set has been used by other authors to show that the sun is constant in output and that the observed variations are explained by errors in the data reduction scheme which failed to remove all the effects of atmospheric extinction or by improper changes in the radiation scale.
Abstract: The Astrophysical Observatory of the Smithsonian Institution (APO) made measurements of the solar constant at many locations on the earth's surface from 1902 to 1962. These measurements have been interpreted by various authors to show that the sun has both a long-term secular change in brightness and cyclic variations. The same data set has been used by other authors to show that the sun is constant in output. The APO solar constant data are reexamined in this review in order to clarify what the APO staff did and what their results say about the behavior of the sun. There are serious problems with the internal consistency of the APO solar constant measurements indicated by the general lack of a common signal between stations or between different measurement methods. If the overall data set is considered, there is no evidence for cyclic variations or any long-term trend in the solar constant greater than a few tenths of a percent. Overall the solar constant appears to be constant to within about 0.1% over the period 1923–1954. Most of the observed variations are explained by errors in the data reduction scheme which failed to remove all the effects of atmospheric extinction or by improper changes in the radiation scale. The solar constant values are independent of solar activity. Although this null conclusion based on the examination of this data set is not encouraging as an easy explanation for climatic change during the twentieth century, the conclusion is valuable in that it sets constraints on the required long-term accuracy and reproducibility needed in the upcoming satellite observations of the solar constant.

67 citations


Journal ArticleDOI
22 Jun 1979-Science
TL;DR: Variations of the solar radius between 1850 and 1937 are limited to about 0.25 arc second; modeling of the sun indicates that the solar constant did not vary by more than 0.3 percent during that time.
Abstract: Climatically significant variation of the solar constant (the energy output of the sun) implies measurable change in the solar radius. The available data limit variations of the solar radius between 1850 and 1937 to about 0.25 arc second; modeling of the sun indicates that the solar constant did not vary by more than 0.3 percent during that time.

63 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of magnetic fields in sunspots and faculae on solar luminosity was investigated using measurements of the solar constant from ground level and from space.
Abstract: The paper presents an investigation into the influence of magnetic fields in sunspots and faculae on solar luminosity, using measurements of the solar constant from ground level and from space. Attention is given to an analysis that shows that it is difficult to devise an atmospheric mechanism that would rapidly lower visible and infrared transmission in response to sunspots, increase it in response to faculae, and anticipate the magnetic development of these features by about one day. It is shown that the phase shift of the luminosity variation provides a promising new technique to determine the depth at which the magnetic fields of sunspots and faculae redistribute the flow of convective energy.

58 citations


Journal ArticleDOI
TL;DR: The question of whether the physical link between solar activity and its suspected influence on weather could be found in the ozone layer has a long history as mentioned in this paper, and attempts to find a connection between the solar cycle and total ozone stayed, not unexpectedly, controversial because the conceivable influences of a variable sun on ozone layer, which are discussed on the basis of modern photochemical theory, are different at different levels and could largely cancel each other in the vertically integrated amount.

30 citations


Journal ArticleDOI
01 Aug 1979-Icarus
TL;DR: In this paper, the influence of ozone in determining the surface temperature of the paleoatmosphere prior to the buildup of molecular oxygen to its present atmospheric level was evaluated. But the present atmospheric values are assumed for the tropospheric water-vapor relative-humidity distribution and lapse rate as well as for the fractional cloud amount and cloud reflectivity.

13 citations


Book ChapterDOI
01 Jan 1979
TL;DR: In this paper, the solar constant is calculated as a function of time using known contrast values for active features on the Sun and the photospheric effective temperature is assumed to be constant.
Abstract: The solar constant is calculated as a function of time using known contrast values for active features on the Sun. The photospheric effective temperature is assumed to be constant in this model and the change in radiant output is assumed to be caused solely by active features on the Sun which have different effective temperatures than the surrounding photosphere. The theoretical annual mean solar constant varies by no more than 0.102 mW cm−2 or 0.075% of its value. For the more active Sun the solar constant is lower. If the energy flux from the deep interior of the Sun is constant on the time scale of a century, the decreased radiant output at sunspot maximum may be balanced by energy storage in the active features or by increased convective energy. A compensating change in the photospheric effective temperature of 1.1°K at sunspot maximum is also sufficient to give a constant solar radiant output.

12 citations


Journal ArticleDOI
TL;DR: In this paper, a solar irradiance measurement made from a balloon on January 27, 1978, indicates a change of +0.4% over similar measurements made in 1968, this change is greater than the experimental uncertainty of the measurement and is felt to be the result of change in the solar constant.
Abstract: Solar irradiance measurement made from a balloon on January 27, 1978, indicates a change of +0.4% over similar measurements made in 1968. This change is greater than the experimental uncertainty of the measurement and is felt to be the result of change in the solar constant.

Book ChapterDOI
01 Jan 1979
TL;DR: In this paper, the authors review the physical origin, spectral nature, energy, and known variability of all solar emanations: photons, particles and fields, and the potential role of line-blanketing as a cause of irradiance change is given.
Abstract: We review the physical origin, spectral nature, energetics and known variability of all solar emanations: photons, particles and fields. The potential role of line-blanketing as a cause of irradiance change is given.

Book ChapterDOI
01 Jan 1979
TL;DR: In this paper, a new dye laser-active cavity radiometer calibration method was proposed to determine spectral irradiance to + 1% accuracy by incorporating a new color dye laser active cavity (LAC) calibration method.
Abstract: It has been hypothesized that the sun’s irradiance may fluctuate at near UV and blue wavelengths due to changes in solar line blanketing associated with solar activity Preliminary determinations of the solar spectral irradiance in the visible spectrum, made over a 6 mo period at the Mauna Loa Observatory, indicated that the solar radiation was constant to at least 1% There were indications, however, that the blue light of the sun (λ ∿ 400 nm) may have varied by a few tenths of one percent It is recommended that solar spectral irradiance be measured in absolute (SI) units so that long-term (decades) changes, that may be related to terrestrial weather, can be quantized It is now possible to determine spectral irradiance to + 1% accuracy by incorporating a new dye laser-active cavity radiometer calibration method

Journal ArticleDOI
TL;DR: In this article, an error occurred during the modification of the basic theoretical calculations of atmospheric transmission to bring them into agreement with insolation values, and four fundamental problems were uncovered: a solar constant was used that is incompatible with Pacrad observations, improper statistical procedures were employed, incorrect dependent variables were chosen for the transmission discrepancy and arithmetical errors occurred.

Book ChapterDOI
01 Jan 1979
TL;DR: The most important parameter in the survey of solar radiation measurement is the energy received outside the earth's atmosphere This parameter has a degree of constancy when compared to that received on the ground Therefore, it is called the solar constant.
Abstract: Publisher Summary This chapter discusses the characteristics of solar radiation The most important parameter in the survey of solar radiation measurement is the energy received outside the earth's atmosphere This parameter has a degree of constancy when compared to that received on the ground Therefore, it is called the solar constant It is defined as the energy received from the sun on unit area exposed normally to the sun's rays at the average sun–earth distance in the absence of the earth's atmosphere The 1970 ISES Congress in Melbourne accepted the value of 1353 W/m 2 for the solar constant with an error of about ± 15% The variability of solar energy incident on a collector surface on the ground is considerably greater than that of the extraterrestrial solar energy On a clear sunshine day, the energy increases from zero at sunrise to a maximum at solar noon and decreases to zero at sunset At any moment, clouds may intercept the sun and decrease the energy to a low value because of the diffuse radiation


01 Jan 1979
TL;DR: In this paper, the effects of two different evaporation parameterizations on the climate sensitivity to solar constant variations were investigated by using a zonally averaged climate model, which is based on a two-level quasi-geostrophic ZONally averaged annual mean model.
Abstract: The effects of two different evaporation parameterizations on the climate sensitivity to solar constant variations are investigated by using a zonally averaged climate model. The model is based on a two-level quasi-geostrophic zonally averaged annual mean model. One of the evaporation parameterizations tested is a nonlinear formulation with the Bowen ratio determined by the predicted vertical temperature and humidity gradients near the earth's surface. The other is the linear formulation with the Bowen ratio essentially determined by the prescribed linear coefficient.

Journal ArticleDOI
TL;DR: In this article, the effect of the distribution of continents and oceans appears in the solution, especially in July, where the largest anomalies are obtained un July over the continents reaching values of -5.1 degrees Celsius at latitude 30° over America and -6.0 degrees at latitude 20° over Asia.
Abstract: According to the computations, a decrease of 2 percent in the present solar constant produces negative anomalies in the surface temperature, witch are stronger in july than in January. The effect of the distribution of continents and oceans appears in the solution, especially in July. The largest anomalies are obtained un July over the continents reaching values of -5.1 degrees Celsius at latitude 30° over America and -6.0 degrees at latitude 20° over Asia. The zonally averaged values of the decrease of surface temperature due to a decrease of 2 percent in the solar constant, in July varying from 2.3° C in lower latitudes to 1.0°C in the higher latitudes. Furthermore, it is shown that decrease of the 2 or 4 percent in the solar constant does not produce a substantial increase in the position of the snow and ice boundary. The anomalies in the cloud cover, that appear due to the decrease in the solar constant, have a strong influence in the surface temperature decrease especially in the lower latitudes . The solution show that it is essential in any climate model to include cloudiness as a variable. The computed annual average value of the change in the surface temperature due to a decrease of one percent is equal to 0.7° C. A comparison with the results obtained by other authors and models is carried out.

01 Jan 1979
TL;DR: The solar constant is defined as the energy received from the sun on unit area exposed normally to the sun's rays at the average sun-earth distance in the absence of the earth's atmosphere as mentioned in this paper.
Abstract: Publisher Summary This chapter discusses the characteristics of solar radiation. The most important parameter in the survey of solar radiation measurement is the energy received outside the earth's atmosphere. This parameter has a degree of constancy when compared to that received on the ground. Therefore, it is called the solar constant. It is defined as the energy received from the sun on unit area exposed normally to the sun's rays at the average sun–earth distance in the absence of the earth's atmosphere. The 1970 ISES Congress in Melbourne accepted the value of 1353 W/m 2 for the solar constant with an error of about ± 1.5%. The variability of solar energy incident on a collector surface on the ground is considerably greater than that of the extraterrestrial solar energy. On a clear sunshine day, the energy increases from zero at sunrise to a maximum at solar noon and decreases to zero at sunset. At any moment, clouds may intercept the sun and decrease the energy to a low value because of the diffuse radiation.

01 Jan 1979
TL;DR: In this article, a quasi-gray model was used to estimate the effects of changes in the abundances of minor infrared absorbers and changes in solar constant or earth albedo.
Abstract: Climate models based on global radiative equilibrium are normally so complicated that they require extensive computer codes to provide adequate accuracy. However, by simply modifying the concept of a gray atmosphere, a reasonably correct mean global temperature is obtained. This elementary model is then used to estimate the effects of changes in the abundances of minor infrared absorbers and changes in the solar constant or earth albedo. When applied to a Budyko-Sellers zonally averaged model, the quasi-gray model could give a physical basis for the latitude dependence of outgoing radiation and of opacity due to H2O vapor content. The latter effect constitutes an important positive feedback on surface temperature.