scholarly journals The Radiant Output of Grenade Glow Clouds in the Lower Thermosphere

1967 ◽  
Vol 20 (6) ◽  
pp. 683 ◽  
Author(s):  
ER Johnson ◽  
KH Lloyd ◽  
CH Low ◽  
LM Sheppard
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Atomic Oxygen ◽  
Lower Thermosphere ◽  
Radiant Energy ◽  
Absorption Cross ◽  
Altitude Range ◽  
Night Time ◽  
Chemiluminescent Reaction

Records of the behaviour of aluminized grenade glow clouds at twilight and at night were obtained using cameras and photometers. From these records the radiance, radiant p~wer, and radiant energy have been deduced for the altitude range 100-200 km. The twilight observations show that the absorption cross section of aluminium monoxide is about 3 X lO-14 cm2? From the night-time results it is concluded that the glow probably arises from a chemiluminescent reaction with atomic oxygen. A set of reactions consistent with the observations above 120 km altitude is

scholarly journals The H Lyman-<font face="Symbol"><b>a</b></font> actinic flux in the middle atmosphere

2003 ◽  
Vol 3 (1) ◽  
pp. 225-231 ◽  
Author(s):  
T. Reddmann ◽  
R. Uhl
Keyword(s):  
Quantum Yield ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Resonance Scattering ◽  
Absorption Cross ◽  
Temperature Dependent ◽  
Actinic Flux ◽  
Dependent Absorption

Abstract. The penetration of solar H Lyman-a radiation into the terrestrial middle atmosphere is studied in detail. The Lyman-a actinic flux is calculated with a Monte Carlo approach including multiple resonance scattering of Lyman-a photons within the terrestrial atmosphere and a temperature dependent absorption cross section of molecular oxygen. The dependence of the actinic flux on the temperature profile is significant for O2 column densities greater than about 1024 m-2. For column densities greater than about 5 · 1024 m-2 resonance scattering becomes important at solar zenith angles > 60°. The O(1D) quantum yield of the O2 dissociation by Lyman-a photons is found to decrease from 0.58 in the lower thermosphere to 0.48 in the lower mesosphere. Parameterisations for Lyman-a actinic flux, mean O2 absorption cross section and O(1D) quantum yield including temperature dependence and resonance scattering are given valid up to a O2 column density of about 1025 m-2.

scholarly journals The H Lyman-α actinic flux in the middle atmosphere

2002 ◽  
Vol 2 (5) ◽  
pp. 1635-1654
Author(s):  
Th. Reddmann ◽  
R. Uhl
Keyword(s):  
Quantum Yield ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Resonance Scattering ◽  
Absorption Cross ◽  
Temperature Dependent ◽  
Actinic Flux ◽  
Dependent Absorption

Abstract. The penetration of solar H Lyman-a radiation into the terrestrial middle atmosphere is studied in detail. The Lyman-a actinic flux is calculated with a Monte Carlo approach including multiple resonance scattering of Lyman-a photons within the terrestrial atmosphere and a temperature dependent absorption cross section of molecular oxygen. The dependence of the actinic flux on the temperature profile is significant for O2 column densities greater than about 1024 m-2. For column densities greater than about 5 · 1024 m-2 resonance scattering becomes important at solar zenith angles > 60°. The \\OD\\ quantum yield of the O2 dissociation by Lyman-aphotons is found to decrease from 0.58 in the lower thermosphere to 0.48 in the lower mesosphere. Parameterisations for Lyman-a actinic flux, mean O2 absorption cross section and \\OD\\quantum yield including temperature dependence and resonance scattering are given valid up to a O2 column density of about 1025 m-2.

Total Absorption Cross Section of Atomic Oxygen below 910 Å

1965 ◽  
Vol 139 (5A) ◽  
pp. A1403-A1407 ◽  
Author(s):  
R. B. Cairns ◽  
James A. R. Samson
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Atomic Oxygen ◽  
Total Absorption ◽  
Absorption Cross

The penetration of solar radiation into the atmosphere

1965 ◽  
Vol 288 (1415) ◽  
pp. 531-539 ◽  
Keyword(s):  
Solar Radiation ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Atomic Oxygen ◽  
Solar Flux ◽  
Ultraviolet Region ◽  
Absorption Cross ◽  
Cross Section Data ◽  
Section Data ◽  
Flux Measurements

Processes causing the attenuation of solar radiation in the ultraviolet region are outlined and absorption cross section data for the major atmospheric constituents evaluated. Recent solar flux measurements through the upper reaches of the atmosphere are considered as a means of providing information about the production of atomic oxygen by the photodissociation of O 2 and O 3 , and the formation of ions and electrons by the photoionization of N 2 , O 2 and O.

scholarly journals Constraining the N<sub>2</sub>O<sub>5</sub> UV absorption cross section from spectroscopic trace gas measurements in the tropical mid-stratosphere

2014 ◽  
Vol 14 (18) ◽  
pp. 9555-9566 ◽  
Author(s):  
L. Kritten ◽  
A. Butz ◽  
M. P. Chipperfield ◽  
M. Dorf ◽  
S. Dhomse ◽  
...  
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Transport Model ◽  
Michelson Interferometer ◽  
Laboratory Data ◽  
Least Square ◽  
Optical Absorption Spectroscopy ◽  
Absorption Cross ◽  
Chemical Transport Model ◽  
Night Time

Abstract. The absorption cross section of N2O5, σN2O5(λ, T), which is known from laboratory measurements with the uncertainty of a factor of 2 (Table 4-2 in (Jet Propulsion Laboratory) JPL-2011; the spread in laboratory data, however, points to an uncertainty in the range of 25 to 30%, Sander et al., 2011), was investigated by balloon-borne observations of the relevant trace gases in the tropical mid-stratosphere. The method relies on the observation of the diurnal variation of NO2 by limb scanning DOAS (differential optical absorption spectroscopy) measurements (Weidner et al., 2005; Kritten et al., 2010), supported by detailed photochemical modelling of NOy (NOx(= NO + NO2) + NO3 + 2N2O5 + ClONO2 + HO2NO2 + BrONO2 + HNO3) photochemistry and a non-linear least square fitting of the model result to the NO2 observations. Simulations are initialised with O3 measured by direct sun observations, the NOy partitioning from MIPAS-B (Michelson Interferometer for Passive Atmospheric Sounding – Balloon-borne version) observations in similar air masses at night-time, and all other relevant species from simulations of the SLIMCAT (Single Layer Isentropic Model of Chemistry And Transport) chemical transport model (CTM). Best agreement between the simulated and observed diurnal increase of NO2 is found if the σN2O5(λ, T) is scaled by a factor of 1.6 ± 0.8 in the UV-C (200–260 nm) and by a factor of 0.9 ± 0.26 in the UV-B/A (260–350 nm), compared to current recommendations. As a consequence, at 30 km altitude, the N2O5 lifetime against photolysis becomes a factor of 0.77 shorter at solar zenith angle (SZA) of 30° than using the recommended σN2O5(λ, T), and stays more or less constant at SZAs of 60°. Our scaled N2O5 photolysis frequency slightly reduces the lifetime (0.2–0.6%) of ozone in the tropical mid- and upper stratosphere, but not to an extent to be important for global ozone.

scholarly journals Photoelectric absorption cross section of silicon near the bandgap from room temperature to sub-Kelvin temperature

AIP Advances ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 025120
Author(s):  
C. Stanford ◽  
M. J. Wilson ◽  
B. Cabrera ◽  
M. Diamond ◽  
N. A. Kurinsky ◽  
...  
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Room Temperature ◽  
Absorption Cross ◽  
Photoelectric Absorption

scholarly journals Ultraviolet Absorption Cross-Sections of Ammonia at Elevated Temperatures for Nonintrusive Quantitative Detection in Combustion Environments

2021 ◽  
pp. 000370282199044
Author(s):  
Wubin Weng ◽  
Shen Li ◽  
Marcus Aldén ◽  
Zhongshan Li
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absorption Cross Section ◽  
Elevated Temperatures ◽  
Uv Absorption ◽  
Energy Utilization ◽  
Quantitative Detection ◽  
Absorption Cross ◽  
Hot Gas

Ammonia (NH3) is regarded as an important nitrogen oxides (NOx) precursor and also as an effective reductant for NOx removal in energy utilization through combustion, and it has recently become an attractive non-carbon alternative fuel. To have a better understanding of thermochemical properties of NH3, accurate in situ detection of NH3 in high temperature environments is desirable. Ultraviolet (UV) absorption spectroscopy is a feasible technique. To achieve quantitative measurements, spectrally resolved UV absorption cross-sections of NH3 in hot gas environments at different temperatures from 295 K to 590 K were experimentally measured for the first time. Based on the experimental results, vibrational constants of NH3 were determined and used for the calculation of the absorption cross-section of NH3 at high temperatures above 590 K using the PGOPHER software. The investigated UV spectra covered the range of wavelengths from 190 nm to 230 nm, where spectral structures of the [Formula: see text] transition of NH3 in the umbrella bending mode, v2, were recognized. The absorption cross-section was found to decrease at higher temperatures. For example, the absorption cross-section peak of the (6, 0) vibrational band of NH3 decreases from ∼2 × 10−17 to ∼0.5 × 10−17 cm2/molecule with the increase of temperature from 295 K to 1570 K. Using the obtained absorption cross-section, in situ nonintrusive quantification of NH3 in different hot gas environments was achieved with a detection limit varying from below 10 parts per million (ppm) to around 200 ppm as temperature increased from 295 K to 1570 K. The quantitative measurement was applied to an experimental investigation of NH3 combustion process. The concentrations of NH3 and nitric oxide (NO) in the post flame zone of NH3–methane (CH4)–air premixed flames at different equivalence ratios were measured.

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