Simulation of solar radiation during a total eclipse: a challenge for radiative transfer

Emde, Claudia; Mayer, Bernhard

doi:10.5194/acp-7-2259-2007

Cited by 97 publications

(118 citation statements)

References 15 publications

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“…The modified extraterrestrial spectrum was used in a 1-D radiative transfer model and the results were in good agreement when compared with measured radiation quantities. Much more accurate results were reported by Emde and Mayer (2007). They used a backward 3-D Monte Carlo method in order to simulate the effect of multiple scattering on irradiance and radiance in the umbral shadow.…”

Section: Introductionmentioning

confidence: 86%

Attenuation of global ultraviolet and visible irradiance over Greece during the total solar eclipse of 29 March 2006

et al. 2007

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Abstract. The variability of ultraviolet and photosynthetically active radiation (PAR) during the total solar eclipse of 29 March 2006 was examined in this study. The measurements from NILU-UV multichannel radiometers at 7 stations of the Greek UV Network were used, where the maximum eclipse percentage ranged from 73.1% to 94.8%. In addition, an extra instrument was established at a remote Greek island, Kastelorizo, which was within the Moon's umbral shadow. The reduction of irradiance at 305 and 312 nm relative to non-eclipse conditions at all sites was almost 1.5 times more than the corresponding decrease in the UVA and visible part of the spectrum and reached 98% for eclipse percentage equal to 94%. The availability of several instruments in close proximity to the path of the umbral shadow provided a challenging test for the models. The measured changes in UV and visible irradiance were compared with 1-D model calculations accounting for the limb darkening effect. The agreement between measurements and modeled values at all sites is within 3% for eclipse percentages of less than 30% and becomes worse as the eclipse progresses. The 1-D model reproduced the spectral effect of the eclipse in UVA and PAR wavelength regions within 3% for eclipse percentages up to 50%, but only the half of the observed change was captured as the eclipse progressed. At three sites, where the eclipse maximum was more than 94%, the measured irradiance at 305 nm for eclipse percentages of more than 85% decreased with slower rates than for longer wavelengths. As a result, the total ozone values, derived from the 305/320 nm ratios, apparently decreased significantly for high eclipse percentages. The effect is similar at all three sites, but the interpretation of this observation remains a challenge. Comparison results with 3-D model calculations shortly before, during and shortly after totality were performed for the first time and revealed an agreement with measurements within 20% in the Correspondence to: A. Kazantzidis (akaza@auth.gr) UV-A region. However, the modeled estimates of irradiance at 312 nm are three times lower than measured values.

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Section: Introductionmentioning

confidence: 86%

Attenuation of global ultraviolet and visible irradiance over Greece during the total solar eclipse of 29 March 2006

et al. 2007

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“…The uncertainty has been estimated from a comparison between SCI-ATRAN and the MYSTIC (Emde and Mayer, 2007) Monte Carlo model (Rozanov et al, 2014). Its contribution to the systematic error of the polarization sensitivities is in general smaller than the error arising from the normalization uncertainty and is therefore not depicted explicitly.…”

Section: Systematic Errorsmentioning

confidence: 99%

In-flight calibration of SCIAMACHY's polarization sensitivity

et al. 2018

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Abstract. This paper describes the in-flight calibration of the polarization response of the SCIAMACHY polarization measurement devices (PMDs) and a selected region of its science channels. With the lack of polarized calibration sources it is not possible to obtain such a calibration from dedicated calibration measurements. Instead, the earthshine itself, together with a simplified radiative transfer model (RTM), is used to derive time-dependent and measurementconfiguration-dependent polarization sensitivities. The results are compared to an instrument model that describes the degradation of the instrument as a result of a slow buildup of contaminant layers on its elevation and azimuth scan mirrors. This comparison reveals significant differences between the model prediction and the data, suggesting an unforeseen change between on-ground and in-flight calibration in at least one of the polarization-sensitive components of the optical bench. The possibility of mechanisms other than scan mirror contamination contributing to the degradation of the instrument will be discussed. The data are consistent with a polarization phase shift occurring in the beam split prism used to divert the light coming from the telescope to the different channels and polarization measurement devices. The extension of the instrument degradation model with a linear retarder enables the determination of the relevant parameters to describe this phase shift and ultimately results in a significant improvement of the polarization measurements as well as the polarization response correction of measured radiances.

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“…Measured surface UV irradiance during the eclipse totality was compared for the first time with 3-D radiative transfer model calculations showing very good performance of the model. Emde and Mayer (2007), for the first time describing the eclipse phenomenon, used a 3-D radiative transfer model to perform backward Monte Carlo calculations. They computed the diffuse radiation in the umbra and simulated the changing colours of the sky.…”

Section: Radiationmentioning

confidence: 99%

The total solar eclipse of March 2006: overview

et al. 2008

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Abstract. This paper provides the overview of an integrated, multi-disciplinary effort to study the effects of the 29 March 2006 total solar eclipse on the environment, with special focus on the atmosphere. The eclipse has been visible over the Eastern Mediterranean, and on this occasion several research and academic institutes organised co-ordinated experimental campaigns, at different distances from eclipse totality and at various environments in terms of air quality. Detailed results and findings are presented in a number of component scientific papers included in a Special Issue of Atmospheric Chemistry and Physics. The effects of the eclipse on meteorological parameters, though very clear, were shown to be controlled by local factors rather than the eclipse magnitudes, and the turbulence activity near surface was suppressed causing a decrease in the Planetary Boundary Layer. In addition to the above, the decrease in solar radiation has caused change to the photochemistry of the atmosphere, with night time chemistry dominating. The abrupt "switch off" of the sun, induced changes also in the ionosphere (140 up to 220 km) and the stratosphere. In the ionosphere, both photochemistry and dynamics resulted to changes in the reflection heights and the electron concentrations. Among the most important scientific findings from the experiments undertaken has been the experimental proof of eclipse induced thermal fluctuations in the ozone layer (Gravity Waves), due to the supersonic movement of the moon's shadow, for the first time with simultaneous measurements at three altitudes namely the troposphere, the stratosphere and the ionosphere.Correspondence to: E. Gerasopoulos (egera@meteo.noa.gr)Within the challenging topics of the experiments has been the investigation of eclipse impacts on ecosystems (field crops and marine plankton). The rare event of a total solar eclipse provided the opportunity to evaluate 1 dimensional (1-D) and three dimensional (3-D) radiative transfer (in the atmosphere and underwater), mesoscale meteorological, regional air quality and photochemical box models, against measurements.

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Simulation of solar radiation during a total eclipse: a challenge for radiative transfer

Cited by 97 publications

References 15 publications

Attenuation of global ultraviolet and visible irradiance over Greece during the total solar eclipse of 29 March 2006

Attenuation of global ultraviolet and visible irradiance over Greece during the total solar eclipse of 29 March 2006

In-flight calibration of SCIAMACHY's polarization sensitivity

The total solar eclipse of March 2006: overview

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