scholarly journals The OI 630.0 and 557.7nm dayglow measured by WINDII and modeled by TRANSCAR

2004 ◽  
Vol 22 (6) ◽  
pp. 1947-1960 ◽  
Author(s):  
F. Culot ◽  
C. Lathuillère ◽  
J. Lilensten ◽  
O. Witasse
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
Satellite Orbit ◽  
Solar Flux ◽  
Emission Rates ◽  
Model Study ◽  
Imaging Interferometer ◽  
Volume Emission ◽  
Measured Volume ◽  
Good Agreement

Abstract. A 1-D fluid/kinetic code is used to model WIND Imaging Interferometer measurements of the atomic oxygen (3P-1D) red and (-1D-1S) green thermospheric dayglows at 630.0nm and 557.7nm. This modelling is performed for different latitude and solar zenith angle conditions, in order to reproduce the measurements all along the satellite orbit. Results are successfully compared to the interferometer's observations, reproducing the measured volume emission rates, together with the maximum emission altitude. A good agreement is found regardless of the position considered along the satellite orbit, meaning that the solar flux and the solar zenith angle influences were successfully taken into account. Together with this model study, a four-year red and green oxygen lines set of WINDII data is analysed with regards to those geophysical parameters. Correlations between volume emission rates and solar flux are evaluated and it is found that the MgII index is better suited to this kind of study than the f10.7 decimetric index.

scholarly journals The O(<sup>1</sup>S) dayglow emission as observed by the WIND imaging interferometer on the UARS

1996 ◽  
Vol 14 (6) ◽  
pp. 637-646 ◽  
Author(s):  
V. Singh ◽  
I. C. McDade ◽  
G. G. Shepherd ◽  
B. H. Solheim ◽  
W. E. Ward
Keyword(s):  
Oxygen Atom ◽  
Atomic Oxygen ◽  
Lower Thermosphere ◽  
Dissociative Recombination ◽  
Model Atmosphere ◽  
Emission Rates ◽  
Imaging Interferometer ◽  
Volume Emission ◽  
Excitation Mechanisms ◽  
Three Body

Abstract. Volume emission rate profiles of the O(1D-1S) 5577 Å dayglow measured by the WIND imaging interferometer on the Upper Atmosphere Research Satellite are analyzed to examine the O(1S) excitation mechanisms in the sunlit lower thermosphere and upper mesosphere. The observed emission profiles are compared with theoretical profiles calculated using a model which takes into account all of the known daytime sources of O(1S). These include photoelectron impact on atomic oxygen, dissociative recombination of O+2, photodissociation of molecular oxygen, energy transfer from metastable N2(A3Σ+u) and three body recombination of atomic oxygen. Throughout most of the thermosphere the measured and modelled emission rates are in reasonably good agreement, given the limitations of the model, but in the region below 100 km, where the oxygen atom recombination source is likely to dominate, the measured emission rates are considerably larger than those modelled using the MSIS-90 oxygen atom densities. This discrepancy is discussed in terms of possible inadequacies in the MSIS-90 model atmosphere and/or additional sources of O(1S) at low altitude.

scholarly journals Using a photochemical model for the validation of NO<sub>2</sub> satellite measurements at different solar zenith angles

2005 ◽  
Vol 5 (2) ◽  
pp. 393-408 ◽  
Author(s):  
A. Bracher ◽  
M. Sinnhuber ◽  
A. Rozanov ◽  
J. P. Burrows
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
Stratospheric Aerosol ◽  
Satellite Measurements ◽  
Imaging Spectrometer ◽  
Diurnal Variability ◽  
Photochemical Model ◽  
Satellite Sensors ◽  
Scanning Imaging ◽  
Good Agreement

Abstract. SCIAMACHY (Scanning Imaging Spectrometer for Atmospheric Chartography) aboard the recently launched Environmental Satellite (ENVISAT) of ESA is measuring solar radiance upwelling from the atmosphere and the extraterrestrial irradiance. Appropriate inversion of the ultraviolet and visible radiance measurements, observed from the atmospheric limb, yields profiles of nitrogen dioxide, NO2, in the stratosphere (SCIAMACHY-IUP NO2 profiles V1). In order to assess their accuracy, the resulting NO2 profiles have been compared with those retrieved from the space borne occultation instruments Halogen Occultation Experiment (HALOE, data version v19) and Stratospheric Aerosol and Gas Experiment II (SAGE II, data version 6.2). As the HALOE and SAGE II measurements are performed during local sunrise or sunset and because NO2 has a significant diurnal variability, the NO2 profiles derived from HALOE and SAGE II have been transformed to those predicted for the solar zenith angles of the SCIAMACHY measurement by using a 1-dimensional photochemical model. The model used to facilitate the comparison of the NO2 profiles from the different satellite sensors is described and a sensitivity ananlysis provided. Comparisons between NO2 profiles from SCIAMACHY and those from HALOE NO2 but transformed to the SCIAMACHY solar zenith angle, for collocations from July to October 2002, show good agreement (within +/-12%) between the altitude range from 22 to 33km. The results from the comparison of all collocated NO2 profiles from SCIAMACHY and those from SAGE II transformed to the SCIAMACHY solar zenith angle show a systematic negative bias of 10 to 35% between 20km to 38km with a small standard deviation between 5 to 14%. These results agree with those of Newchurch and Ayoub (2004), implying that above 20km NO2 profiles from SAGE II sunset are probably somewhat high.

scholarly journals Effects of temperature dependence of reaction N<sub>2</sub>(A<sup>3</sup> <font face="Symbol"><b>S</b></font><b><sup>+</sup><sub>u</sub>)</b> <b>+ O on</b>greenline dayglow emission

2002 ◽  
Vol 20 (12) ◽  
pp. 2039-2045 ◽  
Author(s):  
A. K. Upadhayaya ◽  
V. Singh
Keyword(s):  
Quantum Yield ◽  
Temperature Dependence ◽  
Rate Coefficient ◽  
Solar Flux ◽  
Emission Rates ◽  
Temperature Dependent ◽  
Peak Region ◽  
Dependent Rate ◽  
Volume Emission ◽  
Flux Model

Abstract. The greenline dayglow emission profiles measured by the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS) are modelled using recently proposed revisions to the temperature dependent rate coefficient of the reaction N2 (A3 S+u ) + O in the glow model. The volume emission rates of greenline dayglow emissions are calculated using the Hinteregger et al. (1981) and Tobiska (1991) solar flux models. It is found that the average modelled profiles obtained using the Hinteregger et al. (1981) solar flux model with the temperature dependent rate coefficient and a quantum yield of 0.36 for the reaction N2 (A3 S+u ) + O agree to within 8% of the observed profiles in the thermospheric peak region, which shows significant improvement over the earlier results (20% smaller than WINDII results) obtained using the temperature independent reaction rate coefficient. On the other hand, the average modelled profiles obtained with a temperature dependent rate coefficient in the Tobiska (1991) solar flux model are about 12% higher than the WINDII results, whereas with the temperature independent rate coefficient the results are about 10% smaller than the WINDII results in the thermospheric peak region. The present study reveals that the emission profiles obtained using the Hinteregger et al. (1981) solar flux model, along with the temperature dependent rate coefficient and a quantum yield of 0.36 for the reaction N2 (A3 S+u ) + O in glow model, reproduce the thermospheric emission peak as observed by WINDII, a capability which eluded earlier models. These findings support the newly discovered temperature dependence of the rate coefficient of re-action N2 (A3 S+u ) with O.Key words. Ionosphere (ionization mechanisms; modeling and forecasting; general or miscellaneous)

scholarly journals The morphology of oxygen greenline dayglow emission

1998 ◽  
Vol 16 (12) ◽  
pp. 1599-1606 ◽  
Author(s):  
S. Tyagi ◽  
V. Singh
Keyword(s):  
Cross Sections ◽  
Cosmic Ray ◽  
Rate Coefficients ◽  
Emission Rates ◽  
Ion Chemistry ◽  
Modeling And Forecasting ◽  
Volume Emission ◽  
Qualitative Nature ◽  
Ion Chemistry And Composition ◽  
Good Agreement

Abstract. In this study, the morphology of the oxygen greenline dayglow emission is presented. The volume emission rate profiles are obtained by using Solomon's glow model. The glow model is updated in terms of recent cross sections, reaction rate coefficients and quantum yield of greenline emission. Throughout most of the thermosphere the modelled and observed emission rates are in reasonably good agreement. In the region between 98 and 120 km, the modelled emission rates are substantially higher (about a factor of 1.7) than the observed emission rates. This discrepancy is discussed in terms of scaling of solar fluxes which accounts the variation of solar activity for the day on which calculations are made. The modelled morphology of greenline emission is compared with those cases where WINDII data is available. The modelled and observed morphology is in reasonably good agreement at most of the latitudes above 120 km. In the mesosphere the qualitative nature of morphology is very similar to those of WINDII observation except the modelled emission rates are about a factor of 1.7 higher than the observed emission rates.Keywords. Ionosphere (ion chemistry and composition; modeling and forecasting; solar radiation and cosmic ray effects).

scholarly journals Using photochemical models for the validation of NO<sub>2</sub> satellite measurements at different solar zenith angles

2004 ◽  
Vol 4 (5) ◽  
pp. 5515-5548 ◽  
Author(s):  
A. Bracher ◽  
M. Sinnhuber ◽  
A. Rozanov ◽  
J. P. Burrows
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
Stratospheric Aerosol ◽  
Error Assessment ◽  
Satellite Measurements ◽  
Imaging Spectrometer ◽  
Diurnal Variability ◽  
Satellite Sensors ◽  
Scanning Imaging ◽  
Good Agreement

Abstract. SCIAMACHY (Scanning Imaging Spectrometer for Atmospheric Chartography) aboard the recently launched Environmental Satellite (ENVISAT) of ESA is measuring solar radiance upwelling from the atmosphere and the extraterrestrial irradiance. Appropriate inversion of the ultraviolet and visible radiance measurements, observed from the atmospheric limb, yields profiles of nitrogen dioxide, NO2, in the stratosphere. In order to assess their accuracy, the resulting NO2 profiles have been compared with those retrieved from the space borne occultation instruments Halogen Occultation Experiment (HALOE, data version v19) and Stratospheric Aerosol and Gas Experiment II (SAGE II, data version 6.20). As the HALOE and SAGE II measurements are performed during local sunrise or sunset and because NO2 has a significant diurnal variability, the NO2 profiles derived from HALOE and SAGE II have been transformed to those predicted for the solar zenith angles of the SCIAMACHY measurement by using a 1-D photochemical model. The model used to facilitate the comparison of the NO2 profiles from the different satellite sensors is described and an error assessment provided. Comparisons between NO2 profiles from SCIAMACHY and those from HALOE NO2 but transformed to the SCIAMACHY solar zenith angle, for collocations from July to October 2002, show good agreement (within +/−15%) between the altitude range from 22 to 33 km. The results from the comparison of all collocated NO2 profiles from SCIAMACHY and those from SAGE II transformed to the SCIAMACHY solar zenith angle show a systematic negative bias of 10 to 35% between 20 km to 38 km with a small standard deviation between 5 to 14%. These results agree with those of Newchurch and Ayoub (2004), implying that above 20 km NO2 profiles from SAGE II sunset are probably somewhat high.

Comparison Between POLDER/PARASOL and CERES/AQUA Shortwave Fluxes

2021 ◽  
Author(s):  
Simonne Guilbert ◽  
Frédéric Parol ◽  
Céline Cornet ◽  
Nicolas Ferlay ◽  
François Thieuleux
Keyword(s):  
Climate Change ◽  
Zenith Angle ◽  
Solar Zenith Angle ◽  
Radiant Energy ◽  
Energy System ◽  
The Other ◽  
Monthly Means ◽  
Clear Sky ◽  
The Earth ◽  
Good Agreement

&lt;p&gt;Radiative Budget, essential to the monitoring of climate change, can be investigated with ERB-dedicated instruments like the Clouds and the Earth Radiant Energy System (CERES) instrument (Wielicki, 1996). On the other side, non-dedicated instruments, such as POLDER-3/PARASOL measuring narrowband radiances, can also be used advantageously to obtain shortwave albedos and fluxes (Buriez et al, 2007; Viollier et al, 2002).&lt;/p&gt;&lt;p&gt;We present here a comparison between the shortwave fluxes and albedos derived from POLDER-3 and those derived from CERES flying aboard Aqua, chosen as a reference.&lt;/p&gt;&lt;p&gt;Monthly means of shortwave fluxes computed from the measurements of the two instruments are first set side by side. They show a good agreement in the all-sky case. However, after December 2009, the values from POLDER-3 display a slight drift which coincides with the lowering of the orbit of the PARASOL satellite and the modification of its overpass time in comparison to the other satellites of the A-Train mission. In clear sky situations, greater differences between POLDER and CERES shortwave fluxes are observed, especially over land regions, and the drift increases faster after 2009.&lt;/p&gt;&lt;p&gt;A second comparison is presented, between instantaneous albedos. For the period of coincident observations between POLDER-3 and CERES/Aqua, there is a good correlation between both products. This correlation deteriorates when the comparison is extended after 2009, as the values given by POLDER-3 increase. This result is expected, as the albedo is a function of the Solar Zenith Angle.&lt;/p&gt;&lt;p&gt;The slope of the increase of instantaneous albedo values is higher than for the diurnally extrapolated, monthly averaged shortwave fluxes. This tends to show that the POLDER algorithm leading to the monthly means of diurnal shortwave albedos moderates the increase of instantaneous shortwave albedo values but it doesn&amp;#8217;t completely compensate for the effects of the drift of the instrument.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Effect of solar zenith angle on satellite cloud retrievals based on O2–O2 absorption band

2021 ◽  
Vol 42 (11) ◽  
pp. 4224-4240
Author(s):  
Gyuyeon Kim ◽  
Yong-Sang Choi ◽  
Sang Seo Park ◽  
Jhoon Kim
Keyword(s):  
Absorption Band ◽  
Zenith Angle ◽  
Solar Zenith Angle
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