Characterization of the angular response of a multi-directional spectroradiometer for measuring spectral radiance

Abstract Despite its importance, few instruments are able to measure the angular distribution of the solar spectrum with a high spectral and temporal resolution. We present a novel characterization method of the multi-directional entrance optics of the AMUDIS (Advanced MUltiDIrectional Spectroradiom...

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Main Authors: Mario Tobar Foster, Eduardo Luiz Weide, Angelika Niedzwiedz, Jens Duffert, Gunther Seckmeyer
Format: Article
Language:English
Published: SpringerOpen 2021-07-01
Series:EPJ Techniques and Instrumentation
Subjects:
Online Access:https://doi.org/10.1140/epjti/s40485-021-00069-4
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author Mario Tobar Foster
Eduardo Luiz Weide
Angelika Niedzwiedz
Jens Duffert
Gunther Seckmeyer
author_facet Mario Tobar Foster
Eduardo Luiz Weide
Angelika Niedzwiedz
Jens Duffert
Gunther Seckmeyer
author_sort Mario Tobar Foster
collection DOAJ
description Abstract Despite its importance, few instruments are able to measure the angular distribution of the solar spectrum with a high spectral and temporal resolution. We present a novel characterization method of the multi-directional entrance optics of the AMUDIS (Advanced MUltiDIrectional Spectroradiometer) which is a multidirectional spectroradiometer based on three CCD image sensors combined with imaging spectrographs. The new type of entrance optics consists of 435 different optical fibres uniformly distributed along 145 directions covering the upper hemisphere and allowing simultaneous measurements of the radiance in the ultraviolet, visible and near infrared part of the spectrum, ranging from 280 nm to 1700 nm. The experimental setup for characterizing the multidirectional entrance optics is based on a 100 W halogen lamp and a robotic arm, which moves the lamp tangentially over the surface of a virtual sphere of 102.5 cm radius around the entrance optics. The characterization revealed misalignments in the position of the optical fibres of up to 3∘ (which can affect radiance measurements, specially under broken clouds conditions). The novel characterization method improved 3-fold the alignment up to ±0.1∘
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spelling doaj.art-606f3182e6a840958c059a2378d3beb12022-12-21T20:14:50ZengSpringerOpenEPJ Techniques and Instrumentation2195-70452021-07-018111510.1140/epjti/s40485-021-00069-4Characterization of the angular response of a multi-directional spectroradiometer for measuring spectral radianceMario Tobar Foster0Eduardo Luiz Weide1Angelika Niedzwiedz2Jens Duffert3Gunther Seckmeyer4Institute of Meteorology and Climatology, Leibniz University HannoverInstitute of Meteorology and Climatology, Leibniz University HannoverInstitute of Meteorology and Climatology, Leibniz University HannoverInstitute of Meteorology and Climatology, Leibniz University HannoverInstitute of Meteorology and Climatology, Leibniz University HannoverAbstract Despite its importance, few instruments are able to measure the angular distribution of the solar spectrum with a high spectral and temporal resolution. We present a novel characterization method of the multi-directional entrance optics of the AMUDIS (Advanced MUltiDIrectional Spectroradiometer) which is a multidirectional spectroradiometer based on three CCD image sensors combined with imaging spectrographs. The new type of entrance optics consists of 435 different optical fibres uniformly distributed along 145 directions covering the upper hemisphere and allowing simultaneous measurements of the radiance in the ultraviolet, visible and near infrared part of the spectrum, ranging from 280 nm to 1700 nm. The experimental setup for characterizing the multidirectional entrance optics is based on a 100 W halogen lamp and a robotic arm, which moves the lamp tangentially over the surface of a virtual sphere of 102.5 cm radius around the entrance optics. The characterization revealed misalignments in the position of the optical fibres of up to 3∘ (which can affect radiance measurements, specially under broken clouds conditions). The novel characterization method improved 3-fold the alignment up to ±0.1∘https://doi.org/10.1140/epjti/s40485-021-00069-4Solar radiationSpectroradiometrySpectral radiance
spellingShingle Mario Tobar Foster
Eduardo Luiz Weide
Angelika Niedzwiedz
Jens Duffert
Gunther Seckmeyer
Characterization of the angular response of a multi-directional spectroradiometer for measuring spectral radiance
EPJ Techniques and Instrumentation
Solar radiation
Spectroradiometry
Spectral radiance
title Characterization of the angular response of a multi-directional spectroradiometer for measuring spectral radiance
title_full Characterization of the angular response of a multi-directional spectroradiometer for measuring spectral radiance
title_fullStr Characterization of the angular response of a multi-directional spectroradiometer for measuring spectral radiance
title_full_unstemmed Characterization of the angular response of a multi-directional spectroradiometer for measuring spectral radiance
title_short Characterization of the angular response of a multi-directional spectroradiometer for measuring spectral radiance
title_sort characterization of the angular response of a multi directional spectroradiometer for measuring spectral radiance
topic Solar radiation
Spectroradiometry
Spectral radiance
url https://doi.org/10.1140/epjti/s40485-021-00069-4
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AT eduardoluizweide characterizationoftheangularresponseofamultidirectionalspectroradiometerformeasuringspectralradiance
AT angelikaniedzwiedz characterizationoftheangularresponseofamultidirectionalspectroradiometerformeasuringspectralradiance
AT jensduffert characterizationoftheangularresponseofamultidirectionalspectroradiometerformeasuringspectralradiance
AT guntherseckmeyer characterizationoftheangularresponseofamultidirectionalspectroradiometerformeasuringspectralradiance