OH A2Σ+ –X2Π band ratios observed in the mesosphere by OSIRIS

2008 ◽  
Vol 86 (7) ◽  
pp. 857-862 ◽  
Author(s):  
R L Gattinger ◽  
D A Degenstein ◽  
E J Llewellyn ◽  
M H Stevens
Keyword(s):  
Infrared Imaging ◽  
Vibrational Energy ◽  
Imaging System ◽  
Band System ◽  
Resonance Fluorescence ◽  
Model Predictions ◽  
Spectral Components ◽  
Band Ratios ◽  
Good Agreement

In this study, we present spectra of the mesospheric OH A2Σ+ –X2Π 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 A2Σ+ –X2Π 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 A2Σ+ ν′ = 1 to OH A2Σ+ ν′ = 0. This detailed understanding of the OH A2Σ+ –X2Π 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

scholarly journals Fast NO<sub>2</sub> retrievals from Odin-OSIRIS limb scatter measurements

2011 ◽  
Vol 4 (5) ◽  
pp. 965-972 ◽  
Author(s):  
A. E. Bourassa ◽  
C. A. McLinden ◽  
C. E. Sioris ◽  
S. Brohede ◽  
A. F. Bathgate ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Imaging System ◽  
Computational Cost ◽  
Data Sets ◽  
Proof Of Concept ◽  
Spectral Fitting ◽  
Analysis Technique ◽  
Order Of Magnitude ◽  
Very High ◽  
Good Agreement

Abstract. The feasibility of retrieving vertical profiles of NO2 from space-based measurements of limb scattered sunlight has been demonstrated using several different data sets since the 1980's. The NO2 data product routinely retrieved from measurements made by the Optical Spectrograph and InfraRed Imaging System (OSIRIS) instrument onboard the Odin satellite uses a spectral fitting technique over the 437 to 451 nm range, over which there are 36 individual wavelength measurements. In this work we present a proof of concept technique for the retrieval of NO2 using only 4 of the 36 OSIRIS measurements in this wavelength range, which reduces the computational cost by almost an order of magnitude. The method is an adaptation of a triplet analysis technique that is currently used for the OSIRIS retrievals of ozone at Chappuis band wavelengths. The results obtained are shown to be in very good agreement with the spectral fit method, and provide an important alternative for applications where the computational burden is very high. Additionally this provides a baseline for future instrument design in terms of cost effectiveness and reducing spectral range requirements.

Detection and Modeling of the Core-Annulus Transition in Industrial and Pilot Plant Risers

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Lauren Briens ◽  
Cedric Briens ◽  
David Nevicato ◽  
Jean René Bernard
Keyword(s):  
Pilot Plant ◽  
Signal Analysis ◽  
Optical Probe ◽  
Transition Analysis ◽  
The Core ◽  
Model Predictions ◽  
Vertical Pneumatic Transport ◽  
Probe Measurements ◽  
Good Agreement

The core-annulus structure is essential to the modeling and optimization of riser reactors such as used in Fluid Catalytic Cracking. This paper presents results of measurements taken with various probes in a pilot plant and in an industrial riser. The instantaneous probe signals were analyzed with sophisticated signal analysis methods based on the detection of cycles and the determination of the correlation dimension.In a pilot plant riser, a core-annulus structure was identified with optical and momentum probe measurements. Cycle analysis of the optical probe measurements showed that the annulus was unstable: its thickness fluctuated with an average cycle time of 0.3 s. There were waves at the core-annulus boundary. In an industrial riser, a similar core-annulus structure could be identified with temperature and momentum probe measurements. Local temperature measurements are much easier to perform in an industrial riser than momentum probe measurements but can provide, with cycle analysis, the location of the core-annulus transition. Analysis of the momentum probe and temperature signals showed that the thickness of the wavy transition layer between core and annulus was about the same in the pilot plant and the industrial riser, meaning that the relative range of fluctuations in annulus thickness was much smaller in the larger industrial riser.A model was developed to predict the time-averaged transition between core and annulus. This model, which had been successfully used to predict the annulus thickness in dilute-phase vertical pneumatic transport lines, assumes that the annulus thickness is such that the riser pressure drop is minimized. Measurements and model predictions were in good agreement.

scholarly journals Fast NO<sub>2</sub> retrievals from Odin-OSIRIS limb scatter measurements

2010 ◽  
Vol 3 (6) ◽  
pp. 5499-5519
Author(s):  
A. E. Bourassa ◽  
C. A. McLinden ◽  
C. E. Sioris ◽  
S. Brohede ◽  
E. J. Llewellyn ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Imaging System ◽  
Computational Cost ◽  
Data Sets ◽  
Proof Of Concept ◽  
Spectral Fitting ◽  
Analysis Technique ◽  
Order Of Magnitude ◽  
Very High ◽  
Good Agreement

Abstract. The feasibility of retrieving vertical profiles of NO2 from space-based measurements of limb scattered sunlight has been demonstrated using several different data sets since the 1980's. The NO2 data product routinely retrieved from measurements made by the Optical Spectrograph and InfraRed Imaging System (OSIRIS) instrument onboard the Odin satellite uses a spectral fitting technique over the 437 to 451 nm range, over which there are 36 individual wavelength measurements. In this work we present a proof of concept technique for the retrieval of NO2 using only 4 of the 36 OSIRIS measurements in this wavelength range, which reduces the computational cost by almost an order of magnitude. The method is an adaptation of a triplet analysis technique that is currently used for the OSIRIS retrievals of ozone at Chappuis band wavelengths. The results obtained are shown to be in very good agreement with the spectral fit method, and provide an important alternative for two dimensional tomographic algorithms where the computational burden is very high. Additionally this provides a baseline for future instrument design in terms of cost effectiveness and boosting signal to noise by reducing spectral resolution requirements.

scholarly journals Development of a Near-Infrared Imaging System for Determination of Rice Moisture

2006 ◽  
Vol 83 (5) ◽  
pp. 498-504 ◽  
Author(s):  
Lian-Hsiung Lin ◽  
Fu-Ming Lu ◽  
Yung-Chiung Chang
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Imaging System ◽  
Near Infrared Imaging ◽  
Infrared Imaging System

Numerical and theoretical study of the shock stand-off distance in non-equilibrium flows

2008 ◽  
Vol 607 ◽  
pp. 167-197 ◽  
Author(s):  
N. BELOUAGGADIA ◽  
H. OLIVIER ◽  
R. BRUN
Keyword(s):  
Vibrational Energy ◽  
Physical Modelling ◽  
Relaxation Processes ◽  
Blunt Bodies ◽  
Explicit Formulae ◽  
Insight Into ◽  
Simple Ideal ◽  
Good Agreement ◽  
Non Equilibrium

A theoretical model based on a quasi-one-dimensional formulation is developed which allows determination of the shock stand-off distance at the stagnation point of blunt bodies in hypersonic non-equilibrium flows. Despite the simple ideal dissociating gas model implemented in the theoretical approach, it gives insight into the main physics governing the shock stand-off problem. More detailed and precise data are obtained by a numerical simulation where vibrational and chemical relaxation processes as well as their interactions are taken into account. The physical modelling of these processes is based on a kinetic approach and on a generalized Chapman–Enskog method of solving the Boltzmann equation. Explicit formulae for rate constants and vibrational energy consumption are derived and incorporated into the general conservation equations. Good agreement between theoretical, numerical and experimental results is achieved which ensures a reliable and mutual validation of the different methods.

A Critical Evaluation of Internal Reflection Spectroscopic Methods for Determining Macromolecular Orientation in Polymer Surfaces

1988 ◽  
Vol 42 (7) ◽  
pp. 1258-1265 ◽  
Author(s):  
Francis M. Mirabella
Keyword(s):  
Contact Problem ◽  
Critical Evaluation ◽  
Internal Reflection ◽  
Polymer Surfaces ◽  
X Ray Diffraction ◽  
Single Spectrum ◽  
Band Ratios ◽  
Oriented Polypropylene ◽  
Good Agreement

A critical evaluation was made of the available internal reflection spectroscopic (IRS) methods for the determination of macromolecular orientation in surfaces. A method involving the measurement of band ratios within a single spectrum, which were used to calculate the molecular orientation along the three principle orthogonal axes (MD, TD, and ND), was found to be in good agreement with independent orientation determinations on the same set of oriented polypropylene sheets by x-ray diffraction and polarized refractometry methods. Methods in which dichroic ratios are determined from two separate spectra were shown to lead to unsatisfactory results due to differing sample contact to the internal reflection element (IRE) for each spectrum. This was demonstrated for a method using a rotatable IRE and sample holder which permitted the measurement of spectra along orthogonal axes in the sample without demounting and remounting of the sample. It was found that this method yielded irreproducible results which were not in agreement with the aforementioned independent methods. The reason for the irreproducible results was clearly due to differing sample contact along the two paths through the rotatable IRE—a contact problem that was exacerbated for more highly oriented samples. The conclusion was drawn that only IRS methods involving band ratios within a single spectrum can yield quantitative and reproducible orientation functions, since the sample contact problem does not exist for these methods.

scholarly journals Validation of OSIRIS mesospheric temperatures using satellite and ground-based measurements

2012 ◽  
Vol 5 (4) ◽  
pp. 5493-5526 ◽  
Author(s):  
P. E. Sheese ◽  
K. Strong ◽  
E. J. Llewellyn ◽  
R. L. Gattinger ◽  
J. M. Russell III ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Imaging System ◽  
Temperature Profiles ◽  
Infrared Imaging System ◽  
The University ◽  
First Time ◽  
Continuous Temperature ◽  
Good Agreement

Abstract. The Optical Spectrograph and InfraRed Imaging System (OSIRIS) on the Odin satellite is currently in its 12th year of observing the Earth's limb. For the first time, continuous temperature profiles extending from the stratopause to the upper mesosphere have been derived from OSIRIS observations of Rayleigh-scattered sunlight. OSIRIS temperatures are in good agreement with coincident temperature profiles derived from other satellite and ground-based measurements. In the altitude region of 55–80 km, OSIRIS temperatures are typically within 4–5 K of those from the SABER, ACE-FTS, and SOFIE instruments on the TIMED, SciSat-I, and AIM satellites, respectively. OSIRIS temperatures are typically within 2 K of those from the University of Western Ontario's Purple Crow Lidar in the altitude region of 50–79 km.

COMPARATIVE ACTION OF VARIOUS OESTROGENIC COMPOUNDS ON MOUSE VAGINAL SIALIC ACIDS (II)

1969 ◽  
Vol 62 (4) ◽  
pp. 663-670 ◽  
Author(s):  
Lars Carlborg
Keyword(s):  
Sialic Acid ◽  
Response Curve ◽  
Sialic Acids ◽  
Clear Cut ◽  
Suitable Parameter ◽  
Sufficient Degree ◽  
Comparative Action ◽  
Relative Potencies ◽  
Good Agreement

ABSTRACT Oestrogens administered in lower doses than necessary to induce full cornification of the mouse vagina induce mucification. It was shown previously that the degree of mucification could be estimated by quantitative determination of sialic acids. A suitable parameter for oestrogen assay was the measurement of vaginal sialic acid concentration which exhibited a clear cut dose response curve. Eleven assays of various oestrogens were performed with this method. Their estimated relative potencies were in good agreement with other routine oestrogen assays. A statistically sufficient degree of precision was found. The sensitivity was of the same order, or slightly higher, than the Allen-Doisy test.

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