Comparisons are made of long-term empirical and model-estimated patterns of solar irradiance forcing during a 200-year period (1650-1850), which precedes any apparent anthropogenic influence on climate. This interval encompasses a considerable range (approximately 4 W/m) of estimated variation in solar output, including the ‘‘Maunder’’ and ‘‘Dalton’’ Minima of solar irradiance, and an interveni...

We present a new model for the calculation of the diffuse fraction of the global solar irradiance for solar system simulations. The importance of an accurate estimation of the horizontal diffuse irradiance is highlighted by findings that an inaccurately calculated diffuse irradiance can lead to significant overor underestimations in the annual energy yield of a photovoltaic (PV) system by as mu...

Total solar irradiance reconstructed between 1978 and 2003 using solar surface magnetic field distributions is compared with three composites of total solar irradiance measurements. A good correspondence is found with the total solar irradiance composite from PMOD/WRC, with no bias between the three cycles. The agreement with the other composites (the ACRIM composite, mainly based on the Active...

[1] A phenomenological thermodynamic model is adopted to estimate the relative contribution of the solar-induced versus anthropogenic-added climate forcing during the industrial era. We compare different preindustrial temperature and solar data reconstruction scenarios since 1610. We argue that a realistic climate scenario is the one described by a large preindustrial secular variability (as th...

The identification of flares in solar datasets implies using a thresholding process which excludes the majority of low-emission regions. In this paper we investigate a different measure of solar emission: the distribution of the total solar irradiance when integrated over the disk, obtained using extreme ultraviolet/soft X-ray observations from the SOHO CELIAS/SEM instrument. We show that durin...

Variability of the total solar irradiance (TSI) is a potential contributor to changes in global mean temperature on time scales longer than the relaxation time of the upper ocean (i.e. a few years). Indeed, striking correlations between the global instrumental temperature record, extending back a little more than a century, and observable solar features, most notably the solar cycle length, hav...

Total solar irradiance, the spatially and spectrally integrated radiant output from the Sun at a mean Sun-Earth distance of 1 astronomical unit, provides nearly all the energy driving the Earth’s climate system. Variations in this energy, particularly over long time scales, contribute to changes in Earth’s climate and have been linked to historical glaciation and inter-glacial periods as well a...

The highly variable solar extreme ultraviolet (EUV) radiation is the major energy input to the Earth’s upper atmosphere, strongly impacting the geospace environment, affecting satellite operations, communications, and navigation. The Extreme ultraviolet Variability Experiment (EVE) onboard the NASA Solar Dynamics Observatory (SDO) will measure the solar EUV irradiance from 0.1 to 105 nm with un...

An important question in solar physics is to what extent solar surface magnetism affects the solar irradiance. Previous attempts to answer this question have employed proxies of the magnetic field to reconstruct the irradiance and compare it with observations. Here we present the first model calculations of solar irradiance variations based on variations of the surface distribution of the solar...

Method for error analysis of aerosol parameter estimation with assumed noises which are included in the measured solar direct and diffuse irradiance is proposed. The noises included in the measured solar direct and diffuse irradiance are assumed to be Chi-Square probability density function due to the fact that the measured irradiance is represented as output power which is square of output vol...