Solar UV irradiance variation during cycles 22 and 23

Floyd, L.; Prinz, D. K.; Crane, P. C.; Herring, L. C.

doi:10.1016/s0273-1177(02)00242-9

Cited by 36 publications

(18 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Usually, the Mg II index is constructed to be explicitly unresponsive to responsivity changes which are linear with respect to wavelength. In the years since its original formulation, Mg II core-towing ratios have been derived from the solar UV irradiance measurements from a number of satellite experiments using different instrumental resolutions and algorithms (Weber et al, 1998;Floyd et al, 2002b;de Toma et al, 1997;Viereck et al, 2001;Donnelly and Puga, 1991;. Generally, the algorithms are individually optimized for each instrument to minimize trends and noise in the index product.…”

Section: Solar Activity Indicesmentioning

confidence: 99%

Solar EUV and UV spectral irradiances and solar indices

Floyd¹,

Newmark²,

Cook³

et al. 2005

Journal of Atmospheric and Solar-Terrestrial Physics

View full text Add to dashboard Cite

Section: Solar Activity Indicesmentioning

confidence: 99%

Solar EUV and UV spectral irradiances and solar indices

Floyd¹,

Newmark²,

Cook³

et al. 2005

Journal of Atmospheric and Solar-Terrestrial Physics

View full text Add to dashboard Cite

“…It must be mentioned that the solar constant may vary over the solar cycle, mainly in the very short UV wavelengths (Lean et al, 1992;Kopp and Lean, 2011). In the case of the erythemally weighted irradiance at surface, the wavelength interval of interest starts at 290 nm and therefore the variation is lower than 1 % (Floyd et al, 2002;DeLand and Cebula, 2012;Yeo et al, 2015). Figure 1 shows the relationship between UVER diffuse fraction (f UVER ) and UVER transmissivity (k UVER ), as derived from Eqs.…”

Section: Methodsmentioning

confidence: 99%

Modeling the erythemal surface diffuse irradiance fraction for Badajoz, Spain

2017

View full text Add to dashboard Cite

Abstract. Despite its important role on the human health and numerous biological processes, the diffuse component of the erythemal ultraviolet irradiance (UVER) is scarcely measured at standard radiometric stations and therefore needs to be estimated. This study proposes and compares 10 empirical models to estimate the UVER diffuse fraction. These models are inspired from mathematical expressions originally used to estimate total diffuse fraction, but, in this study, they are applied to the UVER case and tested against experimental measurements. In addition to adapting to the UVER range the various independent variables involved in these models, the total ozone column has been added in order to account for its strong impact on the attenuation of ultraviolet radiation. The proposed models are fitted to experimental measurements and validated against an independent subset. The bestperforming model (RAU3) is based on a model proposed by Ruiz-Arias et al. (2010) and shows values of r 2 equal to 0.91 and relative root-mean-square error (rRMSE) equal to 6.1 %. The performance achieved by this entirely empirical model is better than those obtained by previous semi-empirical approaches and therefore needs no additional information from other physically based models. This study expands on previous research to the ultraviolet range and provides reliable empirical models to accurately estimate the UVER diffuse fraction.

show abstract

“…This aspect of the physics of neutral interstellar gas was implemented in a simplified numerical model by Kyrölä et al (1994) and shortly afterwards in the Warsaw test-particle code, to which we will refer in this paper as the Warsaw model Bzowski & Ruciński 1995a,b;Bzowski et al 1997). Indeed, both the solar EUV flux (Floyd et al 2002) and the solar wind flux (King & Papitashvili 2005) vary considerably during the solar cycle. The result is a solar cycle variation of the solar radiation pressure, of the EUV ionization rate, and of the rate of charge exchange between neutral H atoms and solar wind protons.…”

Section: Article Published By Edp Sciencesmentioning

confidence: 99%

Neutral interstellar hydrogen in the inner heliosphere under the influence of wavelength-dependent solar radiation pressure

Tarnopolski

Bzowski

2008

A&A

View full text Add to dashboard Cite

Context. With the plethora of detailed results from heliospheric missions such as Ulysses and SOHO and at the advent of the first mission dedicated to in situ studies of neutral heliospheric atoms IBEX, we have entered the era of precision heliospheric studies. Interpretation of these data requires precision modeling, with second-order effects quantitatively taken into account. Aims. We study the influence of the non-flat shape of the solar Lyman-α line on the distribution of neutral interstellar hydrogen in the inner heliosphere and assess the importance of this effect for interpretation of heliospheric in situ measurements. Methods. Based on available data, we (i) constructed a model of evolution for the solar Lyman-α line profile with solar activity; (ii) modified an existing test-particle code used to calculate the distribution of neutral interstellar hydrogen in the inner heliosphere so that it takes the dependence of radiation pressure on radial velocity into account; and (iii) compared results of the old and new version. Results. Discrepancies between the classical and Doppler models appear between ∼5 and 3 AU and increase towards the Sun from a few percent to a factor of 1.5 at 1 AU. The classical model overestimates the density everywhere except for a ∼60• cone around the downwind direction, where a density deficit appears. The magnitude of the discrepancies appreciably depends on the phase of the solar cycle, but only weakly on the parameters of the gas at the termination shock. For in situ measurements of neutral atoms performed at ∼1 AU, like those planned for IBEX, the Doppler correction will need to be taken into account, because the modifications include both the magnitude and direction of the local flux by a few km s −1 and degrees, respectively, which, when unaccounted for, would introduce an error of a few km s −1 and degrees in determination of the magnitude and direction of the bulk velocity vector at the termination shock. Conclusions. The Doppler correction is appreciable for in situ observations of neutral H populations and their derivatives performed a few AU from the Sun.

show abstract

Solar UV irradiance variation during cycles 22 and 23

Cited by 36 publications

References 15 publications

Solar EUV and UV spectral irradiances and solar indices

Solar EUV and UV spectral irradiances and solar indices

Modeling the erythemal surface diffuse irradiance fraction for Badajoz, Spain

Neutral interstellar hydrogen in the inner heliosphere under the influence of wavelength-dependent solar radiation pressure

Contact Info

Product

Resources

About