Evaluation of solar spectral irradiance distribution using an index from a limited range of the solar spectrum

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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Atmospheric moisture controls far-red irradiation: a probable impact on the phytochrome

International Agrophysics ◽

10.1515/intag-2015-0033 ◽

2015 ◽

Vol 29 (3) ◽

pp. 283-289 ◽

Cited By ~ 2

Author(s):

Andrzej Doroszewski ◽

Tadeusz Górski ◽

Jerzy Kozyra

Keyword(s):

Water Vapour ◽

Metabolic Pathways ◽

Solar Spectrum ◽

High Irradiance ◽

Spectral Irradiance ◽

Atmospheric Moisture ◽

Solar Spectral Irradiance ◽

Water Vapour Absorption ◽

Probable Impact

Abstract It is commonly accepted that an important role of the phytochrome lies in signalling the proximity of competing plants. However, not all photoresponses conveyed by the phytochrome can be explained by the competition only. Because a better description of the natural variability of solar spectral irradiance is necessary to recognize the other roles of the phytochrome, long-lasting spectroradiometric measurements have been performed. Special attention has been paid to the relations between the far-red and red bands of the solar spectrum, which have an impact on the phytochrome. The effect of atmospheric moisture on far-red irradiance (attenuated in the 720 nm band of water vapour absorption) is described. The far-red irradiance, active in the ‘high irradiance response’ of the phytochrome, and the red/far-red ratio, important for the ‘low fluence response’, may vary very strongly relative to the atmospheric moisture. Together with other facts known from photophysiology, the results of the measurements enabled us to formulate a thesis that the phytochrome monitors the amount of water vapour and opens appropriate metabolic pathways to cope with the danger of drought. The recognition of this novel role of the phytochrome might broaden the knowledge in the area of plant photomorphogenesis and ecology.

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Metrology of the Solar Spectral Irradiance at the Top Of Atmosphere in the Near Infrared Measured at Mauna Loa Observatory: The PYR-ILIOS campaign

10.5194/amt-2018-160 ◽

2018 ◽

Cited By ~ 1

Author(s):

Nuno Pereira ◽

David Bolsée ◽

Peter Sperfeld ◽

Sven Pape ◽

Dominique Sluse ◽

...

Keyword(s):

Near Infrared ◽

Solar Physics ◽

Solar Spectrum ◽

Spectral Irradiance ◽

Radiation Budget ◽

Calibration Source ◽

Error Budget ◽

Mauna Loa ◽

Solar Spectral Irradiance ◽

Earth’S Radiation Budget

Abstract. The near infrared (NIR) part of the solar spectrum is of prime importance for the 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 campaign, which is a replication of the previous IRSPERAD campaign which took place in 2011 at the Izaña 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 in Hawaii (3397 m asl), 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 ATLAS3 for wavelengths above 1.6 μm.

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Irradiance Observations in Near-UV, Visible and Near Infrared Spectral Bands from Measurements Carried out during ATLAS-1 and EURECA-1 Missions

International Astronomical Union Colloquium ◽

10.1017/s0252921100024556 ◽

1994 ◽

Vol 143 ◽

pp. 70-71

Author(s):

Gerard Thuillier ◽

Michel Herse ◽

Dietrich Labs ◽

Paul C. Simon ◽

Didier Gillotay ◽

...

Keyword(s):

Near Infrared ◽

Solar Spectrum ◽

Spectral Irradiance ◽

Solar Spectral Irradiance ◽

Spectral Bands ◽

Percent Difference ◽

Infrared Spectral ◽

Uv Visible ◽

The One ◽

20 Nm

For the ATLAS and EURECA missions, we have used two identical instruments to measure the absolute solar spectral irradiance from 180 to 3200 nm. These instruments are calibrated by use of a blackbody and a set of lamp standards. The measurements are carried out with 1 nm bandpass up to 800 nm and 20 nm above. The instruments and calibration procedures are described by Thuillier et al. (1981). The platform capability of instruments retrieval after measurements allows a post-flight calibration which is essential for accurate measurements. The main results obtained up to now are:- In the UV, the ATLAS-1 and EURECA-1 solar spectral irradiance are consistent with the SpaceLab 1 data obtained in 1983 (Labs et al. 1987). Figure 1 shows the ATLAS 1 and SL 1 spectra. The origin of the existing differences is presently under investigation.- In the visible domain, our measurements agree with the solar spectrum from Neckel & Labs (1984) within a few percent difference at certain wavelength.- In the IR domain, the preliminary processing shows a spectrum close to the one obtained by Thekaekara (1974).

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

Atmospheric Measurement Techniques ◽

10.5194/amt-11-6605-2018 ◽

2018 ◽

Vol 11 (12) ◽

pp. 6605-6615 ◽

Cited By ~ 2

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.

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A high resolution extra-terrestrial solar spectrum determined from ground-based solar irradiance measurements

10.5194/amt-2017-113 ◽

2017 ◽

Author(s):

Julian Gröbner ◽

Ingo Kröger ◽

Luca Egli ◽

Gregor Hülsen ◽

Stefan Riechelmann ◽

...

Keyword(s):

High Resolution ◽

International System ◽

Metrological Traceability ◽

Solar Spectrum ◽

Spectral Irradiance ◽

Atmospheric Research ◽

Solar Spectral Irradiance ◽

Medium Resolution ◽

System Of Units ◽

Unbroken Chain

Abstract. A high resolution extraterrestrial solar spectrum has been determined from ground-based measurements of direct solar spectral irradiance over the range 300 nm to 500 nm using the Langley-plot technique. The measurements were obtained at the Iza\\`na Atmospheric Research Center from AEMET, Tenerife, Spain during the period 12 to 24 September 2016. This solar spectrum (QASUMEFTS) was combined from medium resolution (bandpass of 0.86 nm) measurements of the QASUME spectroradiometer in the range 300 nm to 500 nm and high resolution measurements (0.025 nm) from a fourier transform spectroradiometer over the range 305 nm to 380 nm. The KittPeak solar atlas was used to extend this high resolution solar spectrum to 500 nm. The expanded uncertainties of this solar spectrum are 2 % between 310 nm and 500 nm and 4 % at 300 nm. The comparison of this solar spectrum with solar spectra measured in space (top of the atmosphere) gives very good agreements in some cases, while in some other cases discrepancies of up to 5 % could be observed. The QASUMEFTS solar spectrum represents a benchmark dataset with uncertainties lower than anything previously published. The metrological traceability of the measurements to the International System of Units (SI) is assured by an unbroken chain of calibrations leading to the primary spectral irradiance standard of the Physikalisch-Technische Bundesanstalt in Germany.

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Variations of the Solar Spectral Irradiance

Symposium - International Astronomical Union ◽

10.1017/s0074180900218809 ◽

2001 ◽

Vol 203 ◽

pp. 66-77 ◽

Cited By ~ 1

Author(s):

S. K. Solanki ◽

M. Fligge ◽

Y. C. Unruh

Keyword(s):

Magnetic Field ◽

Solar Cycle ◽

Solar Surface ◽

Solar Spectrum ◽

Spectral Irradiance ◽

Wavelength Band ◽

Relative Variation ◽

Solar Spectral Irradiance ◽

Total Irradiance ◽

The Magnetic Field

The relative variation of the solar irradiance depends strongly on the wavelength band, with the shortest wavelengths exhibiting the largest variations over the solar cycle. This means that not only the total irradiance varies with solar activity but also the shape of the solar spectrum. These measured effects have been successfully modelled. The models indicate that more than 90% of the total and spectral irradiance variations over the solar cycle are due to the magnetic field at the solar surface. The solar spectral irradiance variations play an important part in constraining the models, since they can directly distinguish between changes in the solar effective temperature and changes produced by variations of solar surface magnetic flux. They also help to determine what fraction of the total solar radiative input to Earth is absorbed by the Earth's atmosphere.

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