Retrieval of trace gases from aerosol-influenced infrared transmission spectra observed by low-spectral-resolution Fourier-transform spectrometers

2005 ◽  
Vol 44 (3) ◽  
pp. 455 ◽  
Author(s):  
Nobuyuki Uemura ◽  
Satoshi Kuriki ◽  
Koji Nobuta ◽  
Tatsuya Yokota ◽  
Hideaki Nakajima ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Spectral Resolution ◽  
Trace Gases ◽  
Transmission Spectra ◽  
Infrared Transmission

scholarly journals Deep Learning on Synthesized Sensor Characteristics and Transmission Spectra Enabling MEMS-Based Spectroscopic Gas Analysis beyond the Fourier Transform Limit

Foundations ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 304-317
Author(s):  
Samar Elaraby ◽  
Sherif M. Abuelenin ◽  
Adel Moussa ◽  
Yasser M. Sabry
Keyword(s):  
Fourier Transform ◽  
Spectral Resolution ◽  
Signal To Noise Ratio ◽  
Emerging Market ◽  
Resolution Enhancement ◽  
Fourier Transform Infrared ◽  
Gas Analysis ◽  
Transmission Spectra ◽  
Gas Industry ◽  
Infrared Spectral

Miniaturized Fourier transform infrared spectrometers serve emerging market needs in many applications such as gas analysis. The miniaturization comes at the cost of lower performance than bench-top instrumentation, especially for the spectral resolution. However, higher spectral resolution is needed for better identification of the composition of materials. This article presents a convolutional neural network (CNN) for 3X resolution enhancement of the measured infrared gas spectra using a Fourier transform infrared (FTIR) spectrometer beyond the transform limit. The proposed network extracts a set of high-dimensional features from the input spectra and constructs high-resolution outputs by nonlinear mapping. The network is trained using synthetic transmission spectra of complex gas mixtures and simulated sensor non-idealities such as baseline drifts and non-uniform signal-to-noise ratio. Ten gases that are relevant to the natural and bio gas industry are considered whose mixtures suffer from overlapped features in the mid-infrared spectral range of 2000–4000 cm−1. The network results are presented for both synthetic and experimentally measured spectra using both bench-top and miniaturized MEMS spectrometers, improving the resolution from 60 cm−1 to 20 cm−1 with a mean square error down to 2.4×10−3 in the transmission spectra. The technique supports selective spectral analysis based on miniaturized MEMS spectrometers.

Deuterium Treatment and Infrared Transmission Spectra of Fused Silica

1981 ◽  
Vol 64 (12) ◽  
pp. C-178-C-180 ◽  
Author(s):  
Binod Kumar ◽  
N. Fernelius ◽  
J. A. Detrio
Keyword(s):  
Fused Silica ◽  
Transmission Spectra ◽  
Infrared Transmission

Transport properties of hydrogenated and chlorinated amorphous silicon Correlation with infrared transmission spectra

1984 ◽  
Vol 50 (4) ◽  
pp. 493-504 ◽  
Author(s):  
S. Al Dallal ◽  
S. Kalem ◽  
J. Bourneix ◽  
J. Chevallier ◽  
M. Toulemonde
Keyword(s):  
Amorphous Silicon ◽  
Transport Properties ◽  
Transmission Spectra ◽  
Infrared Transmission

scholarly journals Measurements of hydrogen cyanide (HCN) and acetylene (C<sub>2</sub>H<sub>2</sub>) from the Infrared Atmospheric Sounding Interferometer (IASI)

2013 ◽  
Vol 6 (4) ◽  
pp. 917-925 ◽  
Author(s):  
V. Duflot ◽  
D. Hurtmans ◽  
L. Clarisse ◽  
Y. R'honi ◽  
C. Vigouroux ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Hydrogen Cyanide ◽  
Atmospheric Transport ◽  
Trace Gases ◽  
First Order ◽  
Line Mixing ◽  
Atmospheric Sounding ◽  
First Time ◽  
Order Comparison ◽  
Emission Ratios

Abstract. Hydrogen cyanide (HCN) and acetylene (C2H2) are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm−1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E) and Jungfraujoch (46° N, 8° E) in 2009–2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI). A first order comparison with local ground-based Fourier transform infraRed (FTIR) measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values.

scholarly journals Analysis of new species retrieved from MIPAS

2014 ◽  
Vol 56 ◽  
Author(s):  
Shaomin Cai ◽  
Anu Dudhia
Keyword(s):  
Fourier Transform ◽  
New Species ◽  
High Resolution ◽  
Trace Gases ◽  
Michelson Interferometer ◽  
Emission Spectra ◽  
Fourier Transform Spectrometer ◽  
Mid Infrared ◽  
The Third ◽  
Atmospheric Sounding

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument which operated on the Envisat satellite from 2002-2012 is a Fourier transform spectrometer for the measurement of high-resolution gaseous emission spectra at the Earth's limb. It operates in the near- to mid-infrared, where many of the main atmospheric trace gases have important emission features. The initial operational products were profiles of Temperature, H2O, O3, CH4, N2O, HNO3, and NO2, and this list was recently extended to include N2O5, ClONO2, CFC-11 and CFC-12. Here we present preliminary results of retrievals of the third set of species under consideration for inclusion in the operational processor: HCN, CF4, HCFC-22, COF2 and CCl4.

scholarly journals Localized surface plasmons in structures with linear Au nanoantennas on a SiO2/Si surface

2016 ◽  
Vol 7 ◽  
pp. 1519-1526 ◽  
Author(s):  
Ilya A Milekhin ◽  
Sergei A Kuznetsov ◽  
Ekaterina E Rodyakina ◽  
Alexander G Milekhin ◽  
Alexander V Latyshev ◽  
...  
Keyword(s):  
Penetration Depth ◽  
Surface Plasmons ◽  
Infrared Absorption ◽  
Transmission Spectra ◽  
Localized Surface Plasmons ◽  
Optical Phonons ◽  
Infrared Transmission ◽  
Phonon Modes ◽  
Electromagnetic Simulations

The study of infrared absorption by linear gold nanoantennas fabricated on a Si surface with underlying SiO2 layers of various thicknesses allowed the penetration depth of localized surface plasmons into SiO2 to be determined. The value of the penetration depth derived experimentally (20 ± 10 nm) corresponds to that obtained from electromagnetic simulations (12.9–30.0 nm). Coupling between plasmonic excitations of gold nanoantennas and optical phonons in SiO2 leads to the appearance of new plasmon–phonon modes observed in the infrared transmission spectra the frequencies of which are well predicted by the simulations.

scholarly journals Multi-year comparisons of ground-based and space-borne Fourier transform spectrometers in the high Arctic between 2006 and 2013

2017 ◽  
Vol 10 (9) ◽  
pp. 3273-3294 ◽  
Author(s):  
Debora Griffin ◽  
Kaley A. Walker ◽  
Stephanie Conway ◽  
Felicia Kolonjari ◽  
Kimberly Strong ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Atmospheric Chemistry ◽  
Trace Gases ◽  
Correlation Coefficients ◽  
High Arctic ◽  
Atmospheric Research ◽  
Time Period ◽  
Experiment Validation ◽  
Mean Differences ◽  
Good Agreement

Abstract. This paper presents 8 years (2006–2013) of measurements obtained from Fourier transform spectrometers (FTSs) in the high Arctic at the Polar Environment Atmospheric Research Laboratory (PEARL; 80.05° N, 86.42° W). These measurements were taken as part of the Canadian Arctic ACE (Atmospheric Chemistry Experiment) validation campaigns that have been carried out since 2004 during the polar sunrise period (from mid-February to mid-April). Each spring, two ground-based FTSs were used to measure total and partial columns of HF, O3, and trace gases that impact O3 depletion, namely, HCl and HNO3. Additionally, some tropospheric greenhouse gases and pollutant species were measured, namely CH4, N2O, CO, and C2H6. During the same time period, the satellite-based ACE-FTS made measurements near Eureka and provided profiles of the same trace gases. Comparisons have been carried out between the measurements from the Portable Atmospheric Research Interferometric Spectrometer for the InfraRed (PARIS-IR) and the co-located high-resolution Bruker 125HR FTS, as well as with the latest version of the ACE-FTS retrievals (v3.5). The total column comparison between the two co-located ground-based FTSs, PARIS-IR and Bruker 125HR, found very good agreement for most of these species (except HF), with differences well below the estimated uncertainties ( ≤ 6  %) and with high correlations (R ≥ 0. 8). Partial columns have been used for the ground-based to space-borne comparison, with coincident measurements selected based on time, distance, and scaled potential vorticity (sPV). The comparisons of the ground-based measurements with ACE-FTS show good agreement in the partial columns for most species within 6  % (except for C2H6 and PARIS-IR HF), which is consistent with the total retrieval uncertainty of the ground-based instruments. The correlation coefficients (R) of the partial column comparisons for all eight species range from approximately 0.75 to 0.95. The comparisons show no notable increases of the mean differences over these 8 years, indicating the consistency of these datasets and suggesting that the space-borne ACE-FTS measurements have been stable over this period. In addition, changes in the amounts of these trace gases during springtime between 2006 and 2013 are presented and discussed. Increased O3 (0. 9  %  yr−1), HCl (1. 7  %  yr−1), HF (3. 8  %  yr−1), CH4 (0.5  % yr−1), and C2H6 (2. 3 % yr−1, 2009–2013) have been found with the PARIS-IR dataset, the longer of the two ground-based records.

Retrieval of stratospheric aerosol size and composition information from solar infrared transmission spectra

2003 ◽  
Vol 42 (12) ◽  
pp. 2140 ◽  
Author(s):  
Helen M. Steele ◽  
Annmarie Eldering ◽  
Bhaswar Sen ◽  
Geoffrey C. Toon ◽  
Franklin P. Mills ◽  
...  
Keyword(s):  
Stratospheric Aerosol ◽  
Transmission Spectra ◽  
Infrared Transmission

The spectrum of gaseous methane at 77 K in the 1.1 – 2.6 μm region: a benchmark for planetary astronomy

1989 ◽  
Vol 67 (11) ◽  
pp. 1027-1035 ◽  
Author(s):  
A. R. W. McKellar
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Low Temperature ◽  
Spectral Resolution ◽  
Fourier Transform Spectrometer ◽  
Absorption Cell ◽  
Model Calculations ◽  
Testing Model ◽  
Medium Resolution ◽  
Spectrometer Data

The spectrum of CH4 obtained in CH4 plus N2 mixtures at a temperature of 77 K has been recorded with a spectral resolution of 0.14 cm−1 in the region 3800 to 9100 cm−1. The experiments were performed with long paths (66 or 88 m) in a cooled absorption cell using a Fourier-transform spectrometer. Data are presented here at low and medium resolution, and examples of some spectral regions are also shown at high resolution. The complete results are available from the author in an Appendix. Comparisons are made with previous model calculations of CH4 absorption, and with the observed spectrum of Neptune's satellite, Triton. The results should be useful for the interpretation of the spectra of Triton, Titan, and Pluto. They will also be of value for testing model calculations of low-temperature CH4 absorption, which, thus verified, can be used with greater confidence to analyze observations of Jupiter, Saturn Uranus, and Neptune.

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