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

The JRA-55 Reanalysis: General Specifications and Basic Characteristics

Description of the NCAR Community Atmosphere Model (CAM 3.0)

We examine the sensitivity of a climate model to a wide range of radiative forcings, including changes of solar irradiance, atmospheric CO2, O3, CFCs, clouds, aerosols, surface albedo, and a “ghost” forcing introduced at arbitrary heights, latitudes, longitudes, seasons, and times of day. We show that, in general, the climate response, specifically the global mean temperature change, is sensitive to the altitude, latitude, and nature of the forcing; that is, the response to a given forcing can vary by 50% or more depending upon characteristics of the forcing other than its magnitude measured in watts per square meter. The consistency of the response among different forcings is higher, within 20% or better, for most of the globally distributed forcings suspected of influencing global mean temperature in the past century, but exceptions occur for certain changes of ozone or absorbing aerosols, for which the climate response is less well behaved. In all cases the physical basis for the variations of the response can be understood. The principal mechanisms involve alterations of lapse rate and decrease (increase) of large-scale cloud cover in layers that are preferentially heated (cooled). Although the magnitude of these effects must be model-dependent, the existence and sense of the mechanisms appear to be reasonable. Overall, we reaffirm the value of the radiative forcing concept for predicting climate response and for comparative studies of different forcings; indeed, the present results can help improve the accuracy of such analyses and define error estimates. Our results also emphasize the need for measurements having the specificity and precision needed to define poorly known forcings such as absorbing aerosols and ozone change. Available data on aerosol single scatter albedo imply that anthropogenic aerosols cause less cooling than has commonly been assumed. However, negative forcing due to the net ozone change since 1979 appears to have counterbalanced 30–50% of the positive forcing due to the increase of well-mixed greenhouse gases in the same period. As the net ozone change includes halogen-driven ozone depletion with negative radiative forcing and a tropospheric ozone increase with positive radiative forcing, it is possible that the halogen-driven ozone depletion has counterbalanced more than half of the radiative forcing due to well-mixed greenhouse gases since 1979.

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/96JD03436

Radiative forcing and climate response

Since its first publication in 1973, the HITRAN molecular spectroscopic database has been recognized as the international standard for providing the necessary fundamental spectroscopic parameters for diverse atmospheric and laboratory transmission and radiance calculations. There have been periodic editions of HITRAN over the past decades as the database has been expanded and improved with respect to the molecular species and spectral range covered, the number of parameters included, and the accuracy of this information. The 1996 edition not only includes the customary line-by-line transition parameters familiar to HITRAN users, but also cross-section data, aerosol indices of refraction, software to filter and manipulate the data, and documentation. This paper describes the data and features that have been added or replaced since the previous edition of HITRAN. We also cite instances of critical data that are forthcoming.

https://hitran.org/media/refs/HITRAN-1996.pdf

The hitran molecular spectroscopic database and hawks (hitran atmospheric workstation): 1996 edition

Absolute intensities, self-broadened half-widths, air-broadened half-widths, self-induced and air-induced line shifts were measured in the second overtone (3-0) band of 12 C 16 O at 298 K using a Fourier-transform spectrometer and a multi-spectral-line-fitting technique. The absolute intensity of the band was determined to be (4.62±0.06)×10 −22 cm molecule −1 . The square of the transition moment, |μ0|2, of this band was deduced to be (1.712±0.004)×10 −7 Debye 2 . Herman–Wallis factors were estimated to be C=(1.185±0.009)×10−2 and D=(1.014±0.069)×104. While the line widths were nearly the same as those in the 1-0 and 2-0 bands in both of the cases of broadening studied, the collision-induced line shifts were found to be much larger in the 3-0 band.

Intensities, collision-broadened half-widths, and collision-induced line shifts in the second overtone band of 12C16O

Collision-broadened half-widths of several lines in the nu4 fundamental band of (C-12)H4 have been measured at low temperatures between 130 and 295 K using a tunable diode laser and the sweep integration technique. The broadening gases are H2, N2, He, and Ar. The temperature dependence of the measured line widths is described in terms of an exponent n, which is shown not only to be different for each broadening gas but also to depend upon the tetrahedral symmetry identification of the lines of CH4.

Measurements of collision-broadened line widths in the v4-fundamental band of 12CH4 at low temperatures

Line intensities at 150°K and 295°K, self-broadened half-widths at 171°K, 200°K, 250°K and 295°K, and hydrogen-broadened half-widths at 171°K, 200°K and 295°K have been measured in the ν1+v3 band of C2H2 at 1·525 μm. The absolute intensity of the band has been determined independently by employing the Wilson-Wells-Penner-Weber technique. Our best estimate for the absolute intensity of the band is Sv=7·82 ± 0·07 cm−2 atm−1 at 295°K. Line intensities calculated using this value of Sv are in good agreement with the measured intensities at the two extreme temperatures of 150°K and 295°K considered in the present study, thereby not suggesting any significant intensity anomalies. Line positions have been measured for the first time for this band for R(29)−P(25).

Intensity and half-width measurements in the 1·525 μm band of acetylene☆

Results of high-resolution (0.1 cm/cm) on several CO2-broadened lines in the fundamentals of HCl35 and HCl37. Line intensities, half-widths, and shapes were determined at room temperature. Half-widths in HCl-CO2 collisions were computed for several temperatures, employing Anderson's (1949) theory. The measured shapes of HCl lines broadened by CO2 are described by a semiempirical super-Lorentzian shape. The curve-of-growth for this line shape is derived in terms of a function similar to the Ladenburgh-Reiche function. Absorption between R(0) and P(1) is affected by the appearance of several pressure-induced Q-branch lines, at the pressures from 1 to 10 atm used in the present study.

http://dspace.nitrkl.ac.in:8080/dspace/bitstream/2080/242/1/skso1.pdf

Line shape parameters for HCl and HF in a CO2 atmosphere

Absorption cross-sections, K(sub V)(/(cm)(atm)), have been measured in the 9.2 and 11.8 micrometer bands of CFC-11 (CCl3F) using a high-resolution Fourier transform spectrometer. Temperature and total (N2-broadening) pressure have been varied to obtain results at conditions representative of the atmosphere. The measured absolute intensities (in units of 10(exp -17) cm/molecule of the 9.2 and 11.8 micrometer bands are 2.591 +/- 0.013 and 6.974 +/- 0.038, respectively.

Prasad Varanasi

Papers

Intensities, collision-broadened half-widths, and collision-induced line shifts in the second overtone band of 12C16O

Measurements of collision-broadened line widths in the v4-fundamental band of 12CH4 at low temperatures

Intensity and half-width measurements in the 1·525 μm band of acetylene☆

Line shape parameters for HCl and HF in a CO2 atmosphere

Measurement of the absorption cross-sections of CFC-11 at conditions representing various model atmospheres