Programmable spectral shaping demonstrated at the solar spectral irradiance distribution

Abstract. The tropical stratospheric ozone response to solar UV variations associated with the rotational cycle (~ 27 days) is analysed using MLS satellite observations and numerical simulations from the LMDz-Reprobus chemistry-climate model. The model is used in two configurations, as a chemistry-transport model (CTM) where dynamics are nudged toward ERA-Interim reanalysis and as a chemistry-climate model (free-running) (CCM). An ensemble of five 17 year simulations (1991–2007) is performed with the CCM. All simulations are forced by reconstructed time-varying solar spectral irradiance from the Naval Research Laboratory Solar Spectral Irradiance model. We first examine the ozone response to the solar rotational cycle during two 3 year periods which correspond to the declining phases of solar cycle 22 (10/1991–09/1994) and solar cycle 23 (09/200408/2007) when the satellite ozone observations of the two Microwave Limb Sounders (MLS-UARS and MLS-Aura) are available. In the observations, during the first period, ozone and UV flux are found to be correlated between about 10 and 1 hPa with a maximum of 0.29 at ~ 5 hPa; the ozone sensitivity (% change in ozone for 1 % change in UV) peaks at ~ 0.4. Correlation during the second period is weaker and has a peak ozone sensitivity of only 0.2, possibly due to the fact that the solar forcing is weaker during that period. The CTM simulation reproduces most of these observed features, including the differences between the two periods. The CCM ensemble mean results comparatively show much smaller differences between the two periods, suggesting that the amplitude of the rotational ozone signal estimated from MLS observations or the CTM simulation is strongly influenced by other (non-solar) sources of variability, notably dynamics. The analysis of the ensemble of CCM simulations shows that the estimation of the ensemble mean ozone sensitivity does not vary significantly neither with the amplitude of the solar rotational fluctuations, nor with the size of the time window used for the ozone sensitivity retrieval. In contrast, the uncertainty of the ozone sensitivity estimate significantly increases during periods of decreasing amplitude of solar rotational fluctuations (also coinciding with minimum phases of the solar cycle), and for decreasing size of the time window analysis. We found that a minimum of 3 year and 10 year time window is needed for the 1σ uncertainty to drop below 50 % and 20 %, respectively. These uncertainty sources may explain some of the discrepancies found in previous estimates of the ozone response to the solar rotational cycle.

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Solar spectral irradiance variability of some chromospheric emission lines through the solar activity cycles 21-23

Serbian Astronomical Journal ◽

10.2298/saj160126001g ◽

2017 ◽

pp. 71-86

Author(s):

Ü.D. Göker ◽

M.Sh. Gigolashvili ◽

N. Kapanadze

Keyword(s):

Solar Activity ◽

Chemical Elements ◽

Wave Length ◽

Spectral Lines ◽

Spectral Irradiance ◽

Close Connection ◽

Solar Chromosphere ◽

Solar Spectral Irradiance ◽

Activity Cycles ◽

Solar Activity Cycles

A study of variations of solar spectral irradiance (SSI) in the wave-length ranges 121.5 nm-300.5 nm for the period 1981-2009 is presented. We used various data for ultraviolet (UV) spectral lines and international sunspot number (ISSN) from interactive data centers such as SME (NSSDC), UARS (GDAAC), SORCE (LISIRD) and SIDC, respectively. We reduced these data by using the MATLsoftware package. In this respect, we revealed negative correlations of intensities of UV (289.5 nm-300.5 nm) spectral lines originating in the solar chromosphere with the ISSN index during the unusually prolonged minimum between the solar activity cycles (SACs) 23 and 24. We also compared our results with the variations of solar activity indices obtained by the ground-based telescopes. Therefore, we found that plage regions decrease while facular areas are increasing in SAC 23. However, the decrease in plage regions is seen in small sunspot groups (SGs), contrary to this, these regions in large SGs are comparable to previous SACs or even larger as is also seen in facular areas. Nevertheless, negative correlations between ISSN and SSI data indicate that these variations are in close connection with the classes of sunspots/SGs, faculae and plage regions. Finally, we applied the time series analysis of spectral lines corresponding to the wavelengths 121.5 nm-300.5 nm and made comparisons with the ISSN data. We found an unexpected increase in the 298.5 nm line for the Fe II ion. The variability of Fe II ion 298.5 nm line is in close connection with the facular areas and plage regions, and the sizes of these solar surface indices play an important role for the SSI variability, as well. So, we compared the connection between the sizes of faculae and plage regions, sunspots/SGs, chemical elements and SSI variability. Our future work will be the theoretical study of this connection and developing of a corresponding model.

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SOLAR-v: A new solar spectral irradiance dataset based on SOLAR/SOLSPEC observations during solar cycle 24

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038422 ◽

2020 ◽

Vol 645 ◽

pp. A2

Author(s):

M. Meftah ◽

M. Snow ◽

L. Damé ◽

D. Bolseé ◽

N. Pereira ◽

...

Keyword(s):

Solar Cycle ◽

Spectral Irradiance ◽

Earth’S Atmosphere ◽

Solar Spectral Irradiance ◽

Uv Irradiance ◽

Solar Cycle 24 ◽

Solar Uv ◽

Solar Uv Irradiance ◽

Cycle 24

Context. Solar spectral irradiance (SSI) is the wavelength-dependent energy input to the top of the Earth’s atmosphere. Solar ultraviolet (UV) irradiance represents the primary forcing mechanism for the photochemistry, heating, and dynamics of the Earth’s atmosphere. Hence, both temporal and spectral variations in solar UV irradiance represent crucial inputs to the modeling and understanding of the behavior of the Earth’s atmosphere. Therefore, measuring the long-term solar UV irradiance variations over the 11-year solar activity cycle (and over longer timescales) is fundamental. Thus, each new solar spectral irradiance dataset based on long-term observations represents a major interest and can be used for further investigations of the long-term trend of solar activity and the construction of a homogeneous solar spectral irradiance record. Aims. The main objective of this article is to present a new solar spectral irradiance database (SOLAR-v) with the associated uncertainties. This dataset is based on solar UV irradiance observations (165−300 nm) of the SOLAR/SOLSPEC space-based instrument, which provides measurements of the full-disk SSI during solar cycle 24. Methods. SOLAR/SOLSPEC made solar acquisitions between April 5, 2008 and February 10, 2017. During this period, the instrument was affected by the harsh space environment that introduces instrumental trends (degradation) in the SSI measurements. A new method based on an adaptation of the Multiple Same-Irradiance-Level (MuSIL) technique was used to separate solar variability and any uncorrected instrumental trends in the SOLAR/SOLSPEC UV irradiance measurements. Results. A new method for correcting degradation has been applied to the SOLAR/SOLSPEC UV irradiance records to provide new solar cycle variability results during solar cycle 24. Irradiances are reported at a mean solar distance of 1 astronomical unit (AU). In the 165−242 nm spectral region, the SOLAR/SOLSPEC data agrees with the observations (SORCE/SOLSTICE) and models (SATIRE-S, NRLSSI 2) to within the 1-sigma error envelope. Between 242 and 300 nm, SOLAR/SOLSPEC agrees only with the models.

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Solar spectral irradiance and total solar irradiance at a solar minimum

Geomagnetism and Aeronomy ◽

10.1134/s0016793214070032 ◽

2014 ◽

Vol 54 (7) ◽

pp. 926-932 ◽

Cited By ~ 1

Author(s):

E. E. Benevolenskaya ◽

S. N. Shapovalov ◽

I. G. Kostuchenko

Keyword(s):

Solar Irradiance ◽

Solar Minimum ◽

Total Solar Irradiance ◽

Spectral Irradiance ◽

Solar Spectral Irradiance

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GOES High cadence Operational Total Irradiance: planned data products

10.5194/egusphere-egu21-10348 ◽

2021 ◽

Author(s):

Martin Snow ◽

Stephane Beland ◽

Odele Coddington ◽

Steven Penton ◽

Don Woodraska

Keyword(s):

Extreme Ultraviolet ◽

Solar Spectrum ◽

Total Solar Irradiance ◽

The Other ◽

Spectral Irradiance ◽

First Year ◽

X Ray ◽

Solar Spectral Irradiance ◽

Total Irradiance ◽

High Cadence

The GOES-R series of satellites includes a redesigned instrument for solar spectral irradiance: the Extreme ultraviolet and X-ray Irradiance Sensor (EXIS).&#160; Our team will be using a high-cadence broadband visible light diode to construct a proxy for Total Solar Irradiance (TSI).&#160; This will have two advantages over the existing TSI measurements:&#160; measurements are taken at 4 Hz, so the cadence of our TSI proxy is likely faster than any existing applications, and the observations are taken from geostationary orbit, so the time series of measurements is virtually uninterrupted.&#160; Calibration of the diode measurements will still rely on the standard TSI composites.&#160;&#160;The other measurement from EXIS that will be used is the Magnesium II core-to-wing ratio.&#160; The MgII index is a proxy for chromospheric activity, and is measured by EXIS every 3 seconds.&#160; The combination of the two proxies can be used to generate a model of the full solar spectrum similar to the NRLSSI2 empirical model.We are in the first year of a three-year grant to develop the TSI proxy and the SSI model, so only very preliminary findings will be discussed in this presentation.

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Solar resource assessment with a solar spectral irradiance meter

10.1063/1.4897085 ◽

2014 ◽

Cited By ~ 3

Author(s):

Viktar Tatsiankou ◽

Karin Hinzer ◽

Aaron Muron ◽

Joan Haysom ◽

Henry Schriemer ◽

...

Keyword(s):

Resource Assessment ◽

Spectral Irradiance ◽

Solar Spectral Irradiance ◽

Solar Resource

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