Solar transformities were computed for the solar irradiance spectrum at the top of the Earth’s atmosphere, assuming a model in which the sun radiates as a blackbody with a temperature of 6000 K. Conventionally, the solar transformity (ST) of sunlight reaching the surface of the Earth’s atmosphere has been defined as one. Here, the ST of irradiance at the median wavelength, 794 nm, is defined as...

In the last decade, the photospheric solar metallicity as determined from spectroscopy experienced a remarkable downward revision. Part of this effect can be attributed to an improvement of atomic data and the inclusion of NLTE computations, but also the use of hydrodynamical model atmospheres seemed to play a role. This “decrease” with time of the metallicity of the solar photosphere increased...

Measurements of atmospheric temperature profiles in the troposphere and lower stratosphere were made over Thumba Equatorial Rocket Launching Station (TERLS) (8.5 N, 76.9 E) during a partial solar eclipse (22 July 2009) and an annular solar eclipse (15 January 2010). It was observed that during the partial solar eclipse, the temperature decreased by 2–3 C in the vicinity of the tropopause and in...

The solar radio flux at 10.7 cm has been used in upper atmosphere density modelling because of its correlation with EUV radiation and its long and complete observational record. A proxy, the Mg II index, for the solar chromospheric activity has been derived by Heath and Schlesinger (1986) from Nimbus-7 data. This index allows one to describe the changes occurring in solar-activity in the UV Sun...

The high-resolution measurements of the spectral solar irradiance (SSI) at the top of the Earth’s atmosphere by the Solar Radiation and Climate Experiment (SORCE) satellite are used to examine the magnitude and spectral distribution of the Earth’s entropy flux from the TOA incident solar radiation. Two extreme cases are examined by using Planck expression: I. isotropic hemispheric incident sola...

A solar eclipse is a rare but spectacular natural phenomenon and furthermore it is a challenge for radiative transfer modelling. Whereas a simple one-dimensional radiative transfer model with reduced solar irradiance at the top of the atmosphere can be used to calculate the brightness during partial eclipses a much more sophisticated model is required to calculate the brightness (i.e. the diffu...

The bulk of the sun's radiation is in the visible and infrared. Solar radiation at these wavelengths controls the weather in the lowest levels of the earth's atmosphere. The rate at which this energy is emitted (the so-called solar constant) varies by a few tenths of 1 percent over a time scale of days. Longer period variations may exist, but have yet to be detected. Far more variable are the a...

Currently, the majority of solar observation is performed using ground-based and orbital telescopes, both of which have major limitations. Ground observations are subject to interference from the atmosphere, reducing the quality of solar images and the scientific data that can be collected from them. Orbiting observatories are very expensive, limiting the quantity of such missions and, by exten...

We have made hitherto nearly 1000 determinations of the intensity of solar radiation outside the atmosphere at mean solar distance, termed the solar constant of radiation. The mean value found is 1.93 calories per square centimeter per minute. Langley's spectro-bolometric method was employed. This consists in determining the distribution of the energy in the solar spectrum at different solar ze...