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Emissions from the FeO orange bands have been observed in the laboratory for many decades. The transition has been identified as D([sup.5][Δ.sub.i])-X([sup.5][Δ.sub.i]) where the subscript identifies the five U spin components. While the ground-state molecular constants are well-known, information on the upper state is less precise, and this is primarily due to significant energy level perturbations. Using the available constants, a preliminary spectral simulation model of the orange bands has been developed with a wavelength accuracy of approximately 1/3 nm. Using data from the OSIRIS spectrograph on board the Odin spacecraft, these FeO orange bands have been identified as a component of the night airglow spectrum emanating from the upper mesosphere. The spectral simulation model is combined with the OSIRIS observations to determine the vibrational development of the FeO emissions in the airglow. The model is also applied to published laboratory observations of the orange bands, conducted at much higher pressure than for the airglow, to test for different vibrational development. PACS Nos: 33.20.Kf, 34.50.Ez, 92.60.H-, 92.60.hb, 92.60.hc, 92.60.hw, 95.30.Ft, 95.30.Fg, 95.30.Kr Pendant des decennies, nous avons observe en laboratoire les bandes dans l'orange du FeO. La transition a este; identifiee comme etant D([sup.5][Δ.sub.i])-X([sup.5][Δ.sub.i]), ou l'indice inferieur identifie la composante Ω du spin. Alors que les constantes moleculaires du fondamental sont bien connues, celles de l'etat superieur le sont moins, largement a cause des perturbations entre les niveaux. Utilisant les constantes disponibles, nous avons developpe; un modele preliminaire simulant ces bandes avec une precision sur la longueur d'onde de 1/3 nm. A l'aide des donnees du spectrographe OSIRIS a bord du satellite Odin, nous avons identifie ces bandes dans l'orange comme une composante de la lueur atmospherique nocturne emanant de la mesosphere superieure. Le modele de simulation spectrale est combine avec les observations d'OSIRIS pour obtenir le developpement vibrationnel des emissions de FeO dans la lueur. Nous utilisons aussi le modele en conjonction avec des mesures publiees, obtenues en laboratoire a une pression beaucoup plus eleveee que dans la mesosphere, afin de verifier differents developpements vibrationnels. [Traduit par la Redaction], 1. Introduction The study of the terrestrial night airglow dates back more than a century to the first measurement of the wavelength of the mysterious 'green line' by Angstrom [1], [...]

Temperatures in the mesosphere--lower thermosphere region (MLT) have been derived from the Optical Spectrograph and InfraRed Imaging System (OSIRIS) observations of [O.sub.2] A-band ([b.sup.1][∑.sup.+.sub.g]-[X.sup.3] [∑.sup.-.sub.g])O-O emission spectra. The observed OSIRIS spectra are inverted pixel by pixel, producing inverted volume emission rate spectra at altitudes between 90 and 110 km, which are compared to modelled temperature dependent [O.sub.2] A-band spectra. The estimated accuracy of the retrieved temperatures is approximately ± 2 K near 90 km and up to ± 6 K at higher altitudes. The developed temperature retrieval technique is presented, and some initial retrieval results are briefly discussed. Nous obtenons les temperatures dans la mesosphere-region de basse thermosphere (la basse atmosphere) a partir des observations, par le spectrographe optique et le systeme d'imagerie infrarouge (OSIRIS), des spectres d'emission ([b.sup.1][[suma].sup.+.sub.g][X.sup.3][[suma].sup.-.sub.g])O-O de la bande A de [O.sub.2]. Les spectres observeis par OSIRIS sont inverses pixel par pixel, produisant des spectres de taux d'emission en volume inverse; a des altitudes entre 90 et 110 km, qui sont alors compare;sa des spectres modelises dependant en temperature de la bande A de [O.sub.2]. Les precisions estimeees des temperatures obtenues est approximativement ±2 K pres de 90 km, jusqu'a ±6 K aux altitudes plus elevees. Nous presentons la technique pour obtenir les temperatures et nous discutons quelques resultats preliminaires. [Traduit par la Redaction], 1. Introduction A detailed understanding of the physics and chemistry of the mesosphere--lower thermosphere (MLT) region of the Earth's atmosphere requires an accurate knowledge of the temperature profile in the [...]

Terrestrial auroral spectra over the 275 to 815 nm wavelength range have been recorded by the OSIRIS imaging spectrograph on board the Odin spacecraft. The spectra are from the dark polar region and are averaged over limb tangent altitudes from 100 to 105 km. All wavelengths are exposed simultaneously, thus avoiding the effect of temporal intensity variations inherently present in spectrally scanning systems. Particular care has been taken to quantify the relative spectral sensitivity over the entire wavelength range, and there is an estimated 5% precision in the measurements. To maintain accurate on-orbit spectral calibrations, an atmospheric radiation model with multiple Rayleigh scatter is employed to regularly update the OSIRIS spectral response throughout the mission. A calibrated auroral spectrum is presented, together with matching synthetic spectra for many of the observed features, for potential use as a reference spectrum in general atmospheric research. The relative intensities of the brighter auroral band systems and atomic lines are reviewed. Finally, the observed spectrum is made freely available in digital format in long term archives. PACS Nos: 32.70.Fw, 33.20.Kf, 33.20.Lg, 92.60.hw, 94.05.Hk Nous avons enregistre le spectre auroral terrestre entre 275 et 815 nm a l'aide du spectrographe a imagerie OSIRIS a bord du satellite ODIN. Les spectres sont pour la zone polaire sombre et sont moyennes sur differentes altitudes du limbe entre 100 et 105 km. Toutes les longueurs d'onde sont enregistrees simultaneement, eevitant ainsi les erreurs de variation temporelle d'intensite, pratiquement inherentes dans les systemes a balayage spectral. Nous nous sommes appliques particulierement a quantifier la sensibilite relative spectrale sur l'ensemble du domaine de longueur d'onde et nous atteignons une precision estimeeea 5%. Pour maintenir une calibration spectrale precise en orbite, nous utilisons un modele de radiation atmospheerique avec plusieurs diffuseurs de Rayleigh, afin de mettre a jour regulierement la reponse spectrale d'OSIRIS pendant toute la mission. Nous presentons un spectre auroral calibre;, accompagnee des spectres synthetiques d'appariement pour plusieurs des caracteristiques observeees, qui pourra servir de reference spectrale en recherche atmospherique en general. Nous passons en revue les intensites relatives les plus brillantes des systemes de bandes aurorales et des lignes atomiques. Finalement, nous rendons disponibles les spectres obtenus, sans frais et sous format digital. [Traduit par la Redaction], 1. Introduction The terrestrial auroral spectrum has been studied quantitatively for more than a century. Early ground-based studies include the first measurement of the wavelength of the mysterious 'green line' [...]

The two optically forbidden lines of atomic oxygen, O(¹S-¹D) at 557.7 nm and O([1.sup.S] - ³P) at 297.2 nm, serve as important diagnostics in atmospheric, planetary, and cometary studies. Originating from the same upper state, the emission brightness ratio, B(557.7)B(297.2), must necessarily be constant. The reported emission ratio of these two lines from both theoretical and experimental investigations varies by approximately a factor of two. These two emissions are observed simultaneously in aurora] spectra by the OSIRIS spectrograph on the Odin spacecraft, offering another opportunity to perform the ratio measurement. Because of the considerable wavelength separation between these two atomic lines, precise instrumental relative response calibrations can be problematic. To maintain accurate on-orbit spectral calibrations, an atmospheric radiation model with multiple Rayleigh scatter is employed to constantly track instrumental response. An example of a calibrated single bright aurora] spectrum over the full OSIRIS wavelength range of 275 to 815 nm, limb tangent altitude 105 km, is presented. Using a number of individual auroral spectra, the observed 01557.7 nm brightness is plotted versus the observed 01297.2 nm brightness to both verify the required linear relationship and to experimentally determine the brightness ratio. Spectral contamination by other auroral emission features is removed. From the linear fit, the observed B(557.7)B(297.2) ratio is 9.3 ± 0.5. By comparison, a ratio of 9.8 ± 1 was recently reported, determined by combining results from a number of observational databases separated in time and in wavelength coverage. PACS Nos: 32.30-r, 32.70.Fw, 92.60.hc, 92.60.hw Les deux lignes optiques de l'atome d'oxygene, O(¹S - ¹D) a 557,7 nm et O(¹S - ³P) a 297,2 nm sont d'importants outils de diagnostique dans les etudes sur l'atmosphere, les planetes et les cometes. Provenant du meme etat superieur, le rapport d'emission B(557,7) / B(297,2) doit necessairement etre constant. Il y a un facteur de pres de deux entre les valeurs experimentale et theorique du rapport d'emission de ces deux lignes. Elles sont obseevves simultanement par le spectrographe OSIRIS a bord du satellite Odin, ce qui offre une autre possibilite de mesurer ce rapport. A cause de la grande difference en longueur d'onde entre ces deux lignes atomiques, une calibration instrumentale precise sera problematique. Dans le but de maintenir une calibration precise en orbite, nous utilisons un modele de radiation atmospherique avec diffusion Rayleigh multiple, afm de faire un suivi constant de la reponse instrumentale. Nous presentons un exemple d'un spectre auroral calibre sur l'ensemble du domaine spectral d'OSIRIS, de 275 nm a 815 nm, pris dans le limbe tangent a 105 km d'altitude. Utilisant un certain nombre de spectres d'aurore individuels, nous comparons les graphes d'observation de la brillance d'OI 557,5 et de OI 297,2, pour verifier la linearite et determiner experimental ement le rapport de brillance. Nous eliminons la contamination spectrale provenant d'autres emission aurorales. A partir d'un ajustement numerique lineaire, nous avons determine la valeur du rapport B(557,7) / B(297,2) = 9,3 ± 0,5. Pour fin de comparaison, on a recemment rapporte un rapport de 9,8 ± 1, obtenu en combinant des bases de donnees experimentales separees dans le temps et portant sur diverses longueurs d'onde. [Traduit par la Redaction], 1. Introduction The ratio between the O(¹S-¹D) and O(¹S - ³P) transitions has been the subject of numerous investigations. Some of the early theoretical calculations were conducted by Condon [1] [...]

The visible and near infrared continuum spectrum produced by the NO + O → N[O.sub.2] + hv chemiluminescent reaction has been detected in the upper mesospheric dark polar regions by OSIRIS on the Odin spacecraft. Averaged observed N[O.sub.2] emission spectral shapes are obtained by spectrally resolving the NO + O continuum from the blended strong upper mesospheric OH vibration-rotation airglow bands. The observed continuum spectral shape when compared with laboratory measurements is shifted to lower wavelengths by approximately 20 nm in the steeply sloped 400 to 500 nm region. The observed laboratory continuum spectral shape for upper mesospheric ambient pressure is presented for reference over the 400 to 800 nm region. An example of an N[O.sub.2] continuum volume emission-rate altitude profile derived from a single OSIRIS limb scan is also included. Limb radiantes up to 3 x [10.sup.9] photons [cm.sup.-2] [nm.sup.-1] [s.sup.-1] are observed at the peak of the N[O.sub.2] continuum corresponding to total volume emission rates of approximately 2 x [10.sup.4] photons [cm.sup.-3] [s.sup.-1]. Data extracted from numerous single-volume emission-rate altitude profiles obtained over approximately a 24 h period are assembled into a Southern Hemisphere polar map of the 90 km N[O.sub.2] continuum emission. The map illustrates the considerable spatial brightness variation typically observed in the dark Antarctic polar region throughout the OSIRIS mission dataset. After further analysis these measurements will assist in quantifying the role of thermospheric formed N[O.sub.x] in the catalytic removal of ozone in the upper stratosphere. PACS Nos: 33.20.-t, 34.90.+q, 92.60.H-, 92.60.hc, 92.60.hw L'appareil OSIRIS a bord du satellite Odin a detecte le spectre continu dans le visible et (infrarouge proche produit par la reaction chimioluminescente NO + O → N[O.sub.2] + hv dans la mesosphere superieure des regions polaires sombres. Les moyennes journalieres du spectre d'emission de N[O.sub.2]sont obtenues par resolution spectrale du continu NO + O a partir du melange des fortes bandes de rotation-vibration du OH dans la lueur de haute atmosphere de la mesosphere superieure. La forme spectrale du continu est alors comparee a des mesures en laboratoire et nous observons un deplacement d'environ 20 nm dans la region de forte pente entre 400 et 800 nm. Nous presentons la forme spectral du continu observe en laboratoire comme reference pour le domaine de 400 a 800 nm. Nous incluons egalement un exemple du profile en altitude du taux d'emission en volume du continuum de N[O.sub.2] obtenu d'un simple balayage en elevation par OSIRIS. Nous observons des radiantes de limbe jusqu'a 3 x [10.sup.9] photons [cm.sup.-2] [nm.sup.-1] [s.sup.-1] au maximum du continuum du N[O.sub.2] , correspondant a des taux d'emission totale en volume de 2 x [10.sup.4] photons [cm.sup.-3] [s.sup.-1]. Les donnees obtenues d'un grand nombre de balayages simples sur une periode de 24 h sont rassemblees dans une carte du taux d'emission en volume du continuum de N[O.sub.2] dans la region du pole sud a 90 km d'altitude. La carte illustre les variations spatiales considerables de brillance typiquement observees dans la partie sombre du pole sud, sur toute la banque de donnees de OSIRIS. Apres une analyse plus poussee, ces mesures nous aiderons a quantifier le role du N[O.sub.x] dans (appauvrissement de l'ozone de haute atmosphere. [Traduit par la Redaction], 1. Introduction The importance of nitrogen oxides, N[O.sub.x] = NO + N[O.sub.2], in the catalytic destruction of ozone in the stratosphere is summarized by Funke et al. [1] and supported [...]

In this study, we present spectra of the mesospheric OH [A.sup.2][Σ.sup.+]-[X.sup.2]Π band system, including the 0-0, 1-1, and 1-0 bands, as observed by OSIRIS (Optical Spectrograph and Infrared Imaging System). Spectral components due to Rayleigh-scattered sunlight, lower thermospheric dayglow emission features, and baffle scatter have been removed to isolate the OH emission signature. The observed spectra are compared with model spectra assembled using rotational emission rate factors for solar resonance fluorescence (g-factors) plus prompt emission of the OH [A.sup.2][Σ.sup.+]-[X.sup.2]Π band system from solar Lyman-α photodissociation of water. The observed band ratios are in good agreement with the model values. The altitude variation of the 0-0 band, relative to the 1-1 band, is in agreement with model predictions based on vibrational energy transfer from OH [A.sup.2][Σ.sup.+]v'= 1 to OH [A.sup.2][Σ.sup.+] v' = 0. This detailed understanding of the OH [A.sup.2][Σ.sup.+]-[X.sup.2]Π system is critical for the successful application of OH observations to the determination of mesospheric OH densities and water vapor concentrations. PACS Nos.: 33.20.Lg, 33.20.Tp, 33.70.Fd, 92.60.hc, 92.60.hw Nous presentons ici les resultats d'une etude du systeme de bande [A.sup.2][Σ.sup.+]-[X.sup.2]Π de l'OH mesospherique, incluant les bandes 0-0, 1-1 et 1-0, tels que mesures par OSIRIS (syteme de spectroscopie optique et d'imagerie infra-rouge embarque sur Odin). Nous avons elimine les composants spectraux dus a la diffusion Rayleigh de la lumiere solaire, a la luminescence dans la basse thermosphere et a la diffusion de deflexion, afin de mieux isoler la signature des emissions OH. Les spectres observes sont compares a des spectres composes en utilisant les taux d'emission pour la fluorescence resonante solaire (facteurs g) et l'emission spontanee du systeme de bande OH [A.sup.2][Σ.sup.+]v' = 1 a OH [A.sup.2][Σ.sup.+]v'= 0. La connaissance detaillee du systeme OH [A.sup.2][Σ.sup.+]-[X.sup.2]Π est critique dans l'utilisation des observations OH pour determiner les densites OH et les concentrations de vapeur d'eau mesospheriques. [Traduit par la Redaction], 1. Introduction Since the hydroxyl molecule (OH) has a major impact on ozone ([O.sub.3]) chemistry in the mesosphere, see, for example, ref. 1, it is important to have reliable and [...]

Abstract: A new algorithm, SaskMART, is presented that uses observations of limb-scattered sunlight and a radiative transfer model to determine the ozone number-density profile up to 35 km altitude. In [...]

Abstract: A simple radiative transfer model is developed to calculate the contribution of sea-glint to limb radiance. It is shown that the absolute sea-glint signal peaks between 70. and 80. [...]

Abstract: Since the OH molecule plays a critical role as a catalyst in atmospheric photochemistry, an accurate measurement of the OH density profile covering a broad range of latitudes and [...]

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The analysis of the data from the optical spectrograph and infrared imager system (OSIRIS) that will fly on the Odin satellite requires special attention as many of the measurements will be made in regions of the atmosphere that are relatively close to terminator. Under these conditions the photochemical processes in the upper atmosphere that are responsible for much of the oxygen infrared atmospheric band airglow emission are nonstationary. It is this latter aspect that complicates the retrieval of the mesospheric ozone profile from the OSIRIS observations. However, a tomographic analysis technique that has been developed specifically for the Odin project allows accurate recovery of local volume emission rates in the orbit plane. It is shown that the tomographic analysis technique can be combined with nonstationary atmospheric photochemistry models to recover the mesospheric ozone profile near the terminator. [ABSTRACT FROM AUTHOR]

The Ring effect is measured using the UV-visible spectrometer (∼1 nm spectral resolution) of OSIRIS, the optical spectrograph and infrared imaging system. The observed filling in of Ca(II) H and K (∼395 nm), the two largest Fraunhofer lines in the solar spectrum, are compared with the filling in simulated with a new model that includes rotational Raman scattering (RRS) by N[SUB2] and O[SUB2]. The filling in is (1.06 ± 0:60)% at Ca(II) K and (1.40 ± 0:50)% at Ca(II) H for blue-sky observations at a solar zenith angle of 37°. The measured filling in agrees with the modelled filling in within the uncertainties. [ABSTRACT FROM AUTHOR]