Methane (CH4) is a greenhouse gas which directly influences climate changes on the planet. One of the sources of methane emissions in the atmosphere during human agricultural activities is the decay of animal manure and organic components of agricultural effluents. Therefore, remote control and measurement of the concentrations of agricultural products (mainly methane), which are essentially an anthropogenic factor of the impact on the atmosphere, is important. Here, we consider a possibility of creating a mobile laser absorption complex for methane monitoring at cites with agricultural effluents.
The atmospheric transmission of UV radiation was simulated with use of new data on H2O absorption lines in the 0.25- 0.4 μm spectral region. The transmittance spectra were calculated with the most complete H2O line list POKAZATEL, its new modification in 2020 by Conway et al, refined databank W2020, and new version of popular spectroscopic database HITRAN2020, in which the H2O lines were added in the UV region. The intercomparison of the spectra was made. The water vapor contribution to the atmospheric transfer of solar radiation in the UV region was estimated. The radiative transfer was modeled with taking into account of aerosol and Rayleigh multiple scattering and absorption.
Estimation of contribution of new theoretical lines of water vapor monomer from the POKAZATEL calculations to the absorption of solar radiation in the UV spectral region is made. The atmospheric transmission is calculated with use of different broadening parameters of H2O absorption lines.
The paper discusses calculations of vibrational energy levels for radioactive oxygen isotopologues of water vapor H2XO (where X=11,...,26). A full range of possible water vapor oxygen isotopologues considered. The vibrational levels were calculated in two ways: using the DVR3D variational nuclear motion program and the isotope substitution technique were used. Vibrational energy levels for H211O, H212O, H213O, H214O, H215O, H216O, H217O, H218O, H219O, H220O, H2 21O, H222O, H223O, H224O, H225O и H226O are presented.
The evaluation of the contribution of numerous H2O absorption lines to the atmospheric transmission in the 8-12 μm transparency window is presented based on different spectroscopic databases of water vapor absorption lines, including the new theoretical data sets POKAZATEL and VoTe, as well as the H2O data from the popular spectroscopic databases HITRAN and GEISA. Comparison of the atmospheric transmittance calculated using different databases is presented. The contribution of the weak lines is investigated and shown to be important for very long absorption paths.
The results of the retrievals of methane total column in the atmosphere of Western Siberia using high resolution IR solar spectra registered in May and June 2019 by the Bruker IFS125M Fourier spectrometer are presented. The obtained time series of methane total column are analyzed and compared with the collocated IASI satellite data.
The complete collection of published spectral line parameters of aluminum hydride and deuteride molecules in W@DIS and its parts are described. About 35 information sourses were created and about 60 papers were collected.
The self-broadening coefficients and CO2-broadening coefficients of lines of the main isotope species of SO2 are estimated based on the analysis of literature data. The dependence of the self-broadening parameters on vibrational-rotational quantum numbers is evaluated. In the case of CO2 broadening, the half-widths of lines are calculated using a semiempirical method based on a parametric modification of the impact semiclassical model; the model parameters were determined from the fit to experimental data.
A preliminary version of the line list of dipole-allowed transition of the water molecule is presented. The line lists is created on the basis of VoTe calculations (Voronin, Tennyson et al. in preparation). The cut-of values used for this line list are: 25000 cm-1 in wave number and 10-30 cm/molecule at T=296 K in intensity. Calculated line-lists are available on the site ftp://ftp.iao.ru/pub/VTT/VoTe/.
Estimations of self-broadening, air-broadening and CO2-broadening coefficients of the main isotopic modification of H2S are performed. The result is presented as formulae describing the dependence of self-broadening, CO2- broadening and air-broadening coefficients on rotational quantum numbers of the lower state of a transition. The comparisons of our estimated self-broadening coefficients values with those from the HITRAN and GEISA databases are presented.
The quality of the spectroscopic line parameters from the HITRAN Database for remote sensing of the water vapour isotopic composition of the atmosphere is widely discussed. In this research we show that the HITRAN-2008 data for H2O isotopologues in the near infrared spectral range (4000-6400 cm-1) is reasonably good. The HITRAN data was tested with independent calculation (ab initio et al.). For the evaluation we've used two following criteria: a quality of the fitting of atmospheric spectra measured at the Ural Atmospheric Station (UAS, Kourovka) with the high-resolution Fourier-transform infrared spectrometer and an agreement between the retrieved HDO/H2O relative concentration ratios in the atmospheric column and the results of the simulation of the isotopic general circulation model ECHAM5-wiso (validated for Kourovka region).
The absorption spectrum of monodeuterated water, HDO has been investigated between 11200 and 12400 cm-1. The spectrum has been recorded using IFS-125M interferometer with spectral resolution of 0.05 cm-1. For measurements White’s-type cell were used. The bright light emitting diode (LED) EDEI-1LS3-R was applied as a source of radiation. Signal to noise ratio was about 104. The spectral line parameters - line positions, intensities and half-widths were obtained by least square fitting. As a result of the spectrum analysis the line list containing more than 1500 lines was created. The spectral line parameters have been compared with the previous measured and calculated data.
Estimations of self-broadening coefficients of the main isotopic modification of SO2 are performed. The result is presented as a formulae describing the dependence of self-broadening coefficients on rotational quantum numbers of the lower state of a transition. The comparisons of our estimated self-broadening coefficients values with those from the HITRAN database are presented.
Analysis of the contents of water vapor and aerosol in the atmosphere measured by means of different instruments was performed based on the results of the comprehensive aerosol experiment carried out at the Institute of Atmospheric optics in May 2012. The data obtained using remote (lidar) and contact (balloon) methods were used. They are capable of obtaining the vertical profiles of the measured parameters with high spatial resolution. Lidar measurements of the water vapor content in the boundary layer of the atmosphere by Raman method have shown very good agreement with the data of measurements by balloon. Simultaneous lidar measurements of backscattering and mixing ratio of water vapor in the atmosphere give significant positive correlation of the contents of water vapor and aerosol in the layers.
The passive differential method of measuring of maintenance in the atmosphere of atoms of sodium is offered in a mesosphere with the use of solar radiation. With sufficient good exactness relation of irradiances of the Sun on two near, such that aerosol dispersion and weakening practically identically, wavelengths equal as (λ1/λ2 ))5 . On the basis of analysis of relation of irradiances of a Sun on two wavelengths it is possible to determine the relative changes of maintenance of atoms of sodium in the whole atmospheric colomn.
Three version line-list of dipole transition for isotopic modification of water molecule HD16O are presented. Line-lists have been created on the basis of VTT calculations (Voronin, Tennyson, Tolchenov et al. MNRAS, 2010) by adding air- and self-broadening coefficient, and temperature exponents for HD16O-air case. Three cut-of values for the line intensities were used: 1e-30, 1e-32 and 1e-35 cm/molecule. Calculated line-lists are available on the site ftp://ftp.iao.ru/pub/VTT/VTT-296/.
Air-broadening coefficients of the water isotopologue HD16O up to J = 50 for P, Q and R branches calculated using
different methods are presented. For partially labeled lines (“good” quantum numbers: J, symmetry and level number)
we combined three methods for calculating half-widths: J-dependence and JJ’-dependence up to J=15 and averaging
coefficients calculated using a previously developed semi-empirical method for high J (15-50). For lines with full
assignments based on normal modes v1, v2, v3, Ka, Kc we used: (a) an analytical model (approximation) which depends
on use of rotational quantum numbers J and Ka for both the upper and lower levels; and (b) a method based on the
estimate of the averaged energy differences between coupled states. The comparison of calculated data with broadening
coefficients from HITRAN-2008 and available experimental data is presented. The resulting broadening coefficients can
be used to calculate spectra of water vapor with hundreds millions of weak lines with reasonable accuracy. The line list
VTT [Voronin, Tennyson, Tolchenov, MNRAS, 2010], supporting programs, files for calculations of spectra HD16O and
estimation of broadening coefficient are made freely available also in electronic form via http://www.exomol.com.
The results of study of the atmospheric oxygen complexes (O2)2 by means ground based spectroscopic technique in
Tomsk region, Western Siberia, are presented The absorption of the oxygen complexes (O2)2 has been investigated in the
visible and near-infrared spectral region under clear-sky conditions using a high resolution Fourier transform
spectrometer (FTS) IFS-125 M. The total contents of the atmospheric (O2)2 and O3 absorber were derived from the fit to
experimental data. The seasonal variability of atmospheric oxygen complexes and in addition ozone amounts was
detected. The estimates performed show the dependence of oxygen complexes total contents from temperature.
The new linelist for the water vapor in the 14395-14407 cm-1 region is created with a goal to use the refined line parameters in the atmospheric transmittance calculations. The refinements include i) the line assignments based on accurate line position and strength calculations, ii) new width and pressure shift calculated by semiempirical method, iii) the temperature exponents for each line. The calculation of the atmospheric transmission spectrum has been carried out in this region.
At present some differences are observed between measured and calculated fluxes of solar radiation at the Earth’s surface. According to recent investigations these differences correlate with columnar water vapor. The results of calculation of the contribution of numerous weak absorption lines of water vapor, which usually are not taken into account as applied to atmospheric radiation problems, to the irradiance of the Earth’s surface and spectral brightness of sky are considered. Spatial-angular brightness was modeled in several spectral intervals of near IR and visible ranges at different vision directions and Sun positions. Irradiance of the Earth’s surface was estimated in the range of 4000-20000 cm-1 under different aerosol conditions. It was performed comparative calculations for the HITRAN2000k spectral lines database and Partridge-Schwenke data. The calculated results have shown that the neglect of the contribution of weak absorption lines of water vapor in the near IR and visible regions can lead to errors (to 2% in the 100 cm-1 intervals) in calculation of the diffuse radiation.
The new analysis of water vapor high resolution spectra in 13200 - 16500 cm -1 region has been done using conventional scheme of the effective Hamiltonians in the Pade-Borel approximants representation. About 30 percent of new energy levels has been derived after the spectrum identification including the highest ever observed (0 10 0) [7 0 7] level. An alternative method of the spectrum identification using recent ab initio and variational calculations is discussed.
The H218O spectrum has been recently investigated between 11,300 - 13,600 cm-1 covering the 3v plus (delta) spectral region where v is the quantum of the stretching vibration and (delta) is the quantum of the bending vibration. We present here the study of the 4v and 4v plus (delta) region between 13,000 and 15,500 cm-1. Spectra of 18O enriched water vapor have been recorded by means of Fourier-transform spectroscopy. The experimental details have been discussed. The experimental conditions are given.
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