This paper describes the addition of Collision-Induced Absorption (CIA) into the HITRAN compilation. The data from different experimental and theoretical sources have been cast into a consistent ...format and formalism. The implementation of these new spectral data into the HITRAN database is invaluable for modeling and interpreting spectra of telluric and other planetary atmospheres as well as stellar atmospheres. In this implementation for HITRAN, CIAs of N2, H2, O2, CO2, and CH4 due to various collisionally interacting atoms or molecules are presented. Some CIA spectra are given over an extended range of frequencies, including several H2 overtone bands that are dipole-forbidden in the non-interacting molecules. Temperatures from tens to thousands of Kelvin are considered, as required, for example, in astrophysical analyses of objects, including cool white dwarfs, brown dwarfs, M dwarfs, cool main sequence stars, solar and extra-solar planets, and the formation of so-called first stars.
► Comprehensive compilation of collision-induced absorption cross-sections. ► CIAs of N2, H2, O2, CO2, and CH4 with various perturbing species are considered. ► Experimental and theoretical data are cast into consistent user-friendly format. ► A much-needed tool for atmospheric and astrophysics research is developed.
We demonstrate that a previously proposed model opens the route for the inclusion of refined non-Voigt profiles in spectroscopic databases and atmospheric radiative transfer codes. Indeed, this model ...fulfills many essential requirements: (i) it takes both velocity changes and the speed dependences of the pressure-broadening and -shifting coefficients into account. (ii) It leads to accurate descriptions of the line shapes of very different molecular systems. Tests made for pure H2, CO2 and O2 and for H2O diluted in N2 show that residuals are down to ≃0.2% of the peak absorption, (except for the untypical system of H2 where a maximum residual of ±3% is reached), thus fulfilling the precision requirements of the most demanding remote sensing experiments. (iii) It is based on a limited set of parameters for each absorption line that have known dependences on pressure and can thus be stored in databases. (iv) Its calculation requires very reasonable computer costs, only a few times higher than that of a usual Voigt profile. Its inclusion in radiative transfer codes will thus induce bearable CPU time increases. (v) It can be extended in order to take line-mixing effects into account, at least within the so-called first-order approximation.
•An isolated spectral profile model for non-Voigt effects is presented.•The model takes both velocity changes and the speed dependences effects into account.•It leads to accurate descriptions of the line shapes of very different molecular systems.•It can be calculated with reasonable computer costs.•It can be extended in order to take line-mixing effects into account.
We propose a physically-based methodology for sea-surface skin-temperature (SST) retrievals from daytime spectra recorded by the hyperspectral Infrared Atmospheric Sounding Interferometer (IASI). The ...approach, which takes sun light into account, minimizes the differences between measured and computed radiances at numerous points within two windows centered near 3.7 and 4.0 μm. We demonstrate that, even when the solar contribution is large, with brightness temperatures increased by several tens of kelvin at the shortest wavelengths, very consistent SSTs are retrieved in both windows. Furthermore, the values obtained are, after correction for the cool-skin effect, in excellent agreement (<0.05 K on average) with the in-situ measurements of the depth temperature provided by nearby drifters. This opens renewed perspectives for daytime SST determinations from space, since the IASI mid-infrared windows used here provide SSTs that are, with respect to those retrieved around 9 and 11 μm, much less sensitive to errors in the computed radiative contribution of water vapor.
•SST retrievals using daytime spectra from the infrared hyperspectral sounder IASI.•Successful use of mid-infrared wavelengths despite large contributions of solar light.•High consistency and accuracy of the temperatures retrieved from wavelengths between 3.6 and 4.0 μm.
Abstract
We present the radius–period plot for exoplanet candidates around giant stars. The diagram contains two distinct regions. While planets of giants with radii smaller than 21
R
⊙
exhibit a ...wide range of orbital periods, there is evidently a lack of both relatively short-period (≤300 days) and long-period (≥800 days) planets around bigger stars. In other words, planets around K giants all have similar orbital periods above a certain stellar radius, presumably pointing out a new phenomenon which preferably occurs in stars with radii larger than ∼21
R
⊙
. So far, it is speculative if we are seeing rotational modulation due to some kind of surface structure or an unprecedented form of nonradial stellar oscillations. Consequently, the radius is the second key parameter for giants apart from the stellar mass. Thus, we propose the radius–period plot as a tool to check the plausibility of planetary companions around more challenging host stars by taking into account their stellar identity (e.g., stellar radius and metallicity) to exclude intrinsic stellar variability.
Steroids are small and highly important structural or signalling molecules in living organisms and their metabolism is complex. Due to the multiplicity of enzymes involved there are many different ...steroid related disorders. E.g., an individual enzyme defect is rather rare but can share various clinical symptoms and can thus be hardly diagnosed clinically. Therefore, reliable hormonal determination still presents the most reasonable initial diagnostic approach and helps to avoid uncritical and expensive attempts at molecular diagnostic testing. It also presents a backbone of monitoring these complex patients. In science, reliable hormone measurement is indispensable for the elucidation of new mechanisms of steroid hormone actions. Steroid analytics is highly challenging and should never be considered trivial. Most common methods for steroid determination comprise traditionally immunoassay, or more recently, mass spectrometry based methods. It is absolutely necessary that clinicians and scientists know the methods they are applying by heart. With the introduction of automated direct assays, a loss of quality could be observed over the last two decades in the field of steroid immunoassays. This review wants to meet the need for profound information and orientation in the field of steroid analysis. The pros and cons of the most important methods, such as immunoassays and mass spectrometry based methods will be discussed. The focus of the latter will lie on gas chromatography-mass spectrometry (GC-MS) as well as liquid chromatography-mass spectrometry (LC-MS). Selected analytical applications from our Deutsche Forschungsgemeinschaft Research Group FOR 1369 "Sulfated Steroids in Reproduction" will illustrate the contents. In brief, immunoassays have for long presented the traditional technique for steroid analysis. They are easy to set up. Only one analyte can be measured per immunoassay. Specificity problems can arise and caution has to be exerted especially regarding direct assays lacking purification steps. Mass spectrometry based methods provide structural information on the analyte and thus higher specificity. In combination with chromatographic techniques, they permit the simultaneous determination of a multitude of analytes. Highest specificity can be obtained using GC-MS, a sophisticated but most powerful tool for characterizing steroid metabolomes. LC-MS is a true high throughput technique and highly suited for detecting complex steroids. GC-MS and LC-MS are not competing but complementary techniques. Since reliable steroid determination requires extremely high expertise in the field of analytics as well as steroid biochemistry, it is recommended that collaborations and networking with highly specialized centers of expertise are developed.
The HITRAN2016 molecular spectroscopic database Gordon, I.E.; Rothman, L.S.; Hill, C. ...
Journal of Quantitative Spectroscopy & Radiative Transfer/Journal of quantitative spectroscopy & radiative transfer,
12/2017, Letnik:
203
Journal Article
Recenzirano
Odprti dostop
•HITRAN2016 molecular spectroscopic database is described.•Dynamic web interface at www.hitran.org is introduced.•HITRAN Application Programming Interface is introduced.•Substantial extent of the ...amount and quality of the data highlighted.•Many new spectroscopic parameters are now available in HITRAN.
This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 300 additional molecules important in different areas of atmospheric science have been added to the database. The compilation can be accessed through www.hitran.org. Most of the HITRAN data have now been cast into an underlying relational database structure that offers many advantages over the long-standing sequential text-based structure. The new structure empowers the user in many ways. It enables the incorporation of an extended set of fundamental parameters per transition, sophisticated line-shape formalisms, easy user-defined output formats, and very convenient searching, filtering, and plotting of data. A powerful application programming interface making use of structured query language (SQL) features for higher-level applications of HITRAN is also provided.
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