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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The HITRAN 2008 molecular spectroscopic database

This paper describes the status circa 2001, of the HITRAN compilation that comprises the public edition available through 2001. The HITRAN compilation consists of several components useful for radiative transfer calculation codes: high-resolution spectroscopic parameters of molecules in the gas phase, absorption cross-sections for molecules with very dense spectral features, aerosol refractive indices, ultraviolet line-by-line parameters and absorption cross-sections, and associated database management software. The line-by-line portion of the database contains spectroscopic parameters for 38 molecules and their isotopologues and isotopomers suitable for calculating atmospheric transmission and radiance properties. Many more molecular species are presented in the infrared cross-section data than in the previous edition, especially the chlorofluorocarbons and their replacement gases. There is now sufficient representation so that quasi-quantitative simulations can be obtained with the standard radiance codes. In addition to the description and justification of new or modified data that have been incorporated since the last edition of HITRAN (1996), future modifications are indicated for cases considered to have a significant impact on remote-sensing experiments. (C) 2003 Elsevier Ltd. All rights reserved.

The HITRAN molecular spectroscopic database: edition of 2000 including updates through 2001

The NO2 absorption cross-section has been measured from 42 000 to 10 000 cm−1 (238–1000 nm) with a Fourier transform spectrometer (at the resolution of 2 cm−1, 0.01 nm at 240 nm to 0.2 nm at 1000 nm) and a 5 m temperature controlled multiple reflection cell. The uncertainty on the cross-section is estimated to be less than 3% below 40 000 cm−1 (λ > 250 nm) at 294 K, 3% below 30 000 cm−1 (λ > 333 nm) at 220 K, but reaches 10% for higher wavenumbers. Temperature and pressure effects have been observed. Comparison with data from the literature generally shows a good agreement for wavenumbers between 37 500 and 20 000 cm−1 (267–500 nm). Outside these limits, the difference can reach several percent.

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Measurements of the NO2 absorption cross-section from 42 000 cm−1 to 10 000 cm−1 (238–1000 nm) at 220 K and 294 K

Using the scanning imaging absorption spectrometer for atmospheric chartography (SCIAMACHY) pre-flight model satellite spectrometer, gas-phase absorption spectra of the most important atmospheric trace gases (O3, NO2, SO2, O2, OClO, H2CO, H2O, CO, CO2, CH4, and N2O) have been measured in the 230–2380 nm range at medium spectral resolution and at several temperatures between 203 and 293 K. The spectra show high signal-to-noise ratio (between 200 up to a few thousands), high baseline stability (better than 10−2) and an accurate wavelength calibration (better than 0.01 nm) and were scaled to absolute absorption cross-sections using previously published data. The results are important as reference data for atmospheric remote-sensing and physical chemistry. Amongst other results, the first measurements of the Wulf bands of O3 up to their origin above 1000 nm were made at five different temperatures between 203 and 293 K, the first UV-Vis absorption cross-sections of NO2 in gas-phase equilibrium at 203 K were recorded, and the ultraviolet absorption cross-sections of SO2 were measured at five different temperatures between 203 and 296 K. In addition, the molecular absorption spectra were used to improve the wavelength calibration of the SCIAMACHY spectrometer and to characterize the instrumental line shape (ILS) and straylight properties of the instrument. It is demonstrated that laboratory measurements of molecular trace gas absorption spectra prior to launch are important for satellite instrument characterization and to validate and improve the spectroscopic database.

Measurements of molecular absorption spectra with the SCIAMACHY pre-flight model: instrument characterization and reference data for atmospheric remote-sensing in the 230–2380 nm region

[1] Retrieval uncertainty estimates for vertical tropospheric NO2 columns based on theoretical error source discussions combined with actual Global Ozone Monitoring Experiment (GOME) observations are presented. Contributions to the total retrieval uncertainty are divided into three categories: (1) errors caused by measurement noise and spectral fitting, affecting the slant column density, (2) errors related to the separation of stratospheric and tropospheric NO2 affecting the estimate of the stratospheric slant column, and (3) errors due to uncertainty in model parameters such as clouds, surface albedo, and a priori profile shape, affecting the tropospheric air mass factor. Furthermore, it is shown that a correction for the effective temperature of the trace gas is essential and that a correction for the presence of aerosols needs to be accompanied by aerosol corrections to the cloud retrieval. A discussion of the error components and total retrieval uncertainty is given for March 1997. Tropospheric NO2 columns can be retrieved with a precision of 35–60% over regions with a large contribution of the troposphere to the total column. This error estimate demonstrates the need for highly accurate albedo maps, cloud retrieval schemes, and realistic a priori NO2 profile shapes.

Error analysis for tropospheric NO2 retrieval from space

Measurements of transmission spectra in the infrared have been made in order to test the quality of the theoretical and numerical approach developed in paper I. Two different laboratory experiments have been built which try to simulate optical paths representative of those involved by plume signature. The first, based on a 50 m long White cell and a grating spectrometer, provides experimental results for optical paths of up to about 1 km . These data, representative of the atmospheric paths involved by the considered signature applications, enable a check of the model used for far line wings. In the second set-up, a Fourier transform spectrometer is used with two adjacent cells, which are at high and low temperature, respectively. This configuration schematizes the hot+cold gases that are involved in plume signature. Comparisons between measured and computed values demonstrate the quality of the model and data used. Only small discrepancies remain which are due to imperfections of spectroscopic databases and the neglect of line-mixing effects.

An optimized line by line code for plume signature calculations II. Comparisons with measurements

This work reports on the analysis of the near-UV and visible absorption spectrum of water vapor. Obtained by combining a high- resolution FT spectrometer and a long path White multiple- reflection cell. A large number of water vapor lines belonging to highly excited vibrational levels are identified. Most of these lines have not been observed previously and do not appear in the spectroscopic databases HITRAN and GEISA, widely used for atmospheric calculations. All identified lines are fitted with a Voigt profile using the WSPECTRA program and their cross section and self-broadening parameters at 291 K are determined. A particular attention is give to the integrate cross section over the total spectral range investigated, in order to estimate the contribution of the weak UV-visible water vapor absorption lines to the earth's radiation balance. Preliminary measurements of cross section in the 20000-16000 cm-1 spectral range are also presented.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Absolute intensities of water vapor lines in the near ultraviolet and visible regions

The Fourier transform absorption spectrum of unsaturated water is analysed in order to derive the continuous spectral signature of water vapour in the infrared and visible regions. It is shown that the spectrum consists of a broadband continuum, extending over the entire 2500–22500 cm−1 spectral range investigated, which underlies the vibrational absorption bands of water vapour. This continuum is tentatively attributed to the extinction of light by small water droplets. A careful analysis of the vibrational bands has failed to prove the existence of the narrow band continuum predicted by theory, due to the far-wings of spectral lines or to water dimers.

Laboratory Fourier transform spectroscopy of the water absorption continuum from 2500 to 22500 cm-1

The absorption cross-sections of the O2-02 and 02-N2 collision-induced bands have been measured from 30000 to 7500 cml (333-1333 nm) under conditions prevailing in the Earth's atmosphere. A weak pressure effect on the O2-02 cross-section has been observed. The O2 atmospheric bands have also been measured and their integrated intensities have been determined and compared to previous studies.

Absorption Bands of O2 and its Collision-induced Bands in the 30000-7500 CM-1 Wavenumber Region

New Measurements of the NO2 Absorption Cross-section with a Fourier Transform Spectrometer from 10000 to 42000 cm-1 and its Temperature and Pressure Dependence

M.F. Merienne

Papers

An optimized line by line code for plume signature calculations II. Comparisons with measurements

Absolute intensities of water vapor lines in the near ultraviolet and visible regions

Laboratory Fourier transform spectroscopy of the water absorption continuum from 2500 to 22500 cm-1

Absorption Bands of O2 and its Collision-induced Bands in the 30000-7500 CM-1 Wavenumber Region

New Measurements of the NO2 Absorption Cross-section with a Fourier Transform Spectrometer from 10000 to 42000 cm-1 and its Temperature and Pressure Dependence