scholarly journals Reproducing Solar Spectral Irradiance by LEDs

2020 ◽  
Author(s):  
Anton Kopatsch ◽  
Peter Kary ◽  
Mustafa Özden ◽  
Andreas Albert ◽  
Andrea Ghirardo ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Emission Spectra ◽  
Spectral Irradiance ◽  
Light Sources ◽  
Reference Spectrum ◽  
Ir Radiation ◽  
Solar Spectral Irradiance ◽  
Research Areas ◽  
American Society ◽  
New Applications

Abstract The development of light-emitting diodes (LEDs) of different emission spectra is revolutionizing lighting technology and opening up completely new applications and research areas. The spectral irradiance of the sun reaching the Earth's surface is very complex due to radiative transfer processes within the atmosphere and ranges from the shortwave ultraviolet (UV) to longwave infrared (IR) radiation. The simulation of this spectral irradiance by artificial light sources is technically very demanding. It could be realized sufficiently so far by a combination of different light sources, mostly light bulbs, metal halide lamps and fluorescent tubes, in combination of different filters. In the present work, we are presenting a new LED Sun Simulator system, which allows simulating spectral irradiance close to natural solar spectral irradiance from 360 to 800 nm. The system generates the spectral irradiance by a combination of 23 different types of LED. The irradiance of each of the 23 different LED types can be separately controlled by software to modulate the spectra. In total, the system comprises 2,530 high-power LEDs mounted on 100 printed circuit boards (PCBs) / aluminum boards. With this system, an experimental area of one square meter can be homogeneously irradiated (irradiance with a mean variability of 2 % in the integrated range of 360 nm - 800 nm) at the distance of 1.6 m simulating the spectral irradiance of the standard reference spectrum of the American Society for Testing and Materials (ASTM G173-03). At maximum, the LED lighting field can reach an irradiance of 2,500 W m-2, which is more than twice than that of the brightest sunlight in Central Europe. Thus, the new system opens up multiple new applications in many research areas ranging from photobiology to human health and environmental and material sciences.

scholarly journals Metrology of solar spectral irradiance at the top of the atmosphere in the near infrared measured at Mauna Loa Observatory: the PYR-ILIOS campaign

2018 ◽  
Vol 11 (12) ◽  
pp. 6605-6615 ◽  
Author(s):  
Nuno Pereira ◽  
David Bolsée ◽  
Peter Sperfeld ◽  
Sven Pape ◽  
Dominique Sluse ◽  
...  
Keyword(s):  
Near Infrared ◽  
Solar Physics ◽  
Solar Spectrum ◽  
Spectral Irradiance ◽  
Radiation Budget ◽  
Reference Spectrum ◽  
Calibration Source ◽  
Mauna Loa ◽  
Solar Spectral Irradiance ◽  
Earth’S Radiation Budget

Abstract. The near-infrared (NIR) part of the solar spectrum is of prime importance for solar physics and climatology, directly intervening in the Earth's radiation budget. Despite its major role, available solar spectral irradiance (SSI) NIR datasets, space-borne or ground-based, present discrepancies caused by instrumental or methodological reasons. We present new results obtained from the PYR-ILIOS SSI NIR ground-based campaign, which is a replication of the previous IRSPERAD campaign which took place in 2011 at the Izaña Atmospheric Observatory (IZO). We used the same instrument and primary calibration source of spectral irradiance. A new site was chosen for PYR-ILIOS: the Mauna Loa Observatory (MLO) in Hawaii (3397 m a.s.l.), approximately 1000 m higher than IZO. Relatively to IRSPERAD, the methodology of monitoring the traceability to the primary calibration source was improved. The results as well as a detailed error budget are presented. We demonstrate that the most recent results, from PYR-ILIOS and other space-borne and ground-based experiments, show an NIR SSI lower than the previous reference spectrum, ATLAS3, for wavelengths above 1.6 µm.

scholarly journals On the 1/f noise in the UV solar spectral irradiance

2013 ◽  
Vol 114 (3-4) ◽  
pp. 725-727 ◽  
Author(s):  
Costas A. Varotsos ◽  
Irina Melnikova ◽  
Maria N. Efstathiou ◽  
Chris Tzanis
Keyword(s):  
Spectral Irradiance ◽  
Solar Spectral Irradiance

scholarly journals Sensitivity of the tropical stratospheric ozone response to the solar rotational cycle in observations and chemistry-climate model simulations

2017 ◽  
Author(s):  
Rémi Thiéblemont ◽  
Marion Marchand ◽  
Slimane Bekki ◽  
Sébastien Bossay ◽  
Franck Lefèvre ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Climate Model ◽  
Time Window ◽  
Stratospheric Ozone ◽  
Spectral Irradiance ◽  
Naval Research ◽  
Solar Spectral Irradiance ◽  
Model Free ◽  
Ozone Sensitivity ◽  
Ensemble Mean

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.

Surface plasmon polariton nanolasers: Coherent light sources for new applications

2018 ◽  
Vol 27 (11) ◽  
pp. 114208 ◽  
Author(s):  
Yu-Hsun Chou ◽  
Chia-Jui Chang ◽  
Tzy-Rong Lin ◽  
Tien-Chang Lu
Keyword(s):  
Surface Plasmon ◽  
Surface Plasmon Polariton ◽  
Light Sources ◽  
Coherent Light ◽  
Plasmon Polariton ◽  
New Applications

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

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.

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

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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