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

Spectral transmission of IR radiation through the nitrogen-broadened lines of the nu-3 fundamental of N2O has been measured at 154, 202 and 300 K. A value of 1411 + or - 54 per sq cm per atmosphere at STP has been obtained for the combined strength of the nu-3 and nu-2(1) + nu-3 - nu-2(1) bands, using the Wilson-Wells-Penner-Weber method. This value of the combined strength, the relative intensity calculations of Gray Young, the room-temperature data of Toth for nitrogen-broadened half-widths in the nu-1 + nu-3 and 2nu2(0) + nu-3 bands, and the variation of the line width with temperature proposed by Varanasi and Sarangi are shown to yield excellent agreement between the measured and computed spectral transmittance throughout the band.

Intensity and transmission measurements in the ν3-fundamental of N2O at low temperatures

Absolute intensities in the 1000-0l10 band of 12C16O2 at 720.8 cm−1 have been measured at 295 K using the Doppler-limited spectral resolution (∼10−4 cm−1) of a tunable diode laser. Our highly accurate measurements differ significantly from previously published and cataloged data.

Intensity measurements in the 720.8‐cm−1 Q branch of 12C16O2

Absolute intensities of the J -multiplets P (1)- P (8), R (0)- R (7) and of the Q -branch in the 2 v 3 -band of 13 CH 4 have been measured at 100, 150, 200, and 296°K. Our intensity data confirm the recent observation by Fox et al. that substitution of the isotope 13 C for the central 12 C atom in methane results in significantly different line strengths in the severely perturbed 2 v 3 -band. Our results at 296°K for the absolute intensities of R (0) and R (1) are in excellent agreement with the values measured by Fox et al.

Intensity measurements in the 2v3-band of 13CH4 at low temperatures☆

Absolute intensities of seven lines in the P-branch of the v1-fundamental band of 14N216O at 7.78 μm have been measured at 295 K using a tunable diode laser and the sweep-integration technique.

Line strength measurements in the nu1-fundamental band of (N2-14)O-16 using a tunable diode laser

Nitrogen-broadened halfwidths of rotational lines of CH3D have been deduced from spectral transmittance measurements in the nu2-fundamental at 100 and 200 K with a spectral resolution of 0.06 per cm. The line widths appear to be 1.5 times larger and exhibit the same 1/T dependence on temperature as lines of CH4.

Prasad Varanasi

Papers

Intensity and transmission measurements in the ν3-fundamental of N2O at low temperatures

Intensity measurements in the 720.8‐cm−1 Q branch of 12C16O2

Intensity measurements in the 2v3-band of 13CH4 at low temperatures☆

Line strength measurements in the nu1-fundamental band of (N2-14)O-16 using a tunable diode laser

Nitrogen-broadened lines of monodeuterated methane in the 4.5 μm region at low temperatures.