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

Presented integrated intensity data at 300 K for J multiplets between P(11) and R(11) in the nu-3 fundamental of C-12 methane are shown to be in good agreement with most previously published pertinent values. Also, line widths measured at 100 K, 130 K, 190 K, 250 K, and 300 K for R(0), R(1), and R(2) broadened by He, Ne, and Ar are presented, and the line-width temperature dependence is discussed for the three cases of broadening.

Measurement of multiplet intensities and noble gas-broadened line widths in the V3-fundamental of methane

Integrated intensities of acetylene bands at 3.04, 7.53, and 13.7 microns measured at 300 K at a spectral resolution of 0.6 slit widths per cm, using the technique described by Penner (1959), are presented. Comparisons with other published measurements suggest that the presented intensity values are reasonably well determined.

Measurement of integrated intensities of acetylene bands at 3·04, 7·53 and 13·7 μm

Spectral absorption coefficients k(v) in the atmospheric window are reported for CFC-11 and CFC-12. Data obtained with a grating spectrometer are compared with NCAR cross sections and measurements of k(v) made with a tunable diode laser spectrometer at various temperature-pressure combinations representing tangent heights or layers in the atmosphere are presented. The results are suitable for atmospheric remote sensing and global warming studies.

Absorption coefficients of CFC-11 and CFC-12 needed for atmospheric remote sensing and global warming studies

A tunable diode laser spectrometer and the sweep integration technique were used to measure hydrogen-broadened half-widths and nitrogen-broadened half-widths of eight lines between P(1) and P(15) in the CO fundamental at several temperatures between 94 and 298 K. The results are of interest in connection with studies of the atmospheres of earth, Jupiter, Saturn, and Titan.

Diode laser measurements of CO line widths at planetary atmospheric temperatures

We present measurements of the absolute intensities, N2-, O2-, and air-broadened half-widths of spectral lines in the 4.5 μm (ν3-fundamental) band of 14 N 2 16 O at 216, 250 and 296 K . These data were obtained using a high-resolution ( 0.002 cm −1 ) Fourier-transform spectrometer. The variation of the line widths with temperature and the rotational quantum number m (|m| is J in the P-branch and J+1 in the R-branch, with J being the rotational quantum number of a linear molecule) is examined. Simple empirical polynomial (quartic) fits of the measured half-widths are presented. A new improved method of extrapolation of line-width data to higher values of m has also been devised.

Prasad Varanasi

Papers

Measurement of multiplet intensities and noble gas-broadened line widths in the V3-fundamental of methane

Measurement of integrated intensities of acetylene bands at 3·04, 7·53 and 13·7 μm

Absorption coefficients of CFC-11 and CFC-12 needed for atmospheric remote sensing and global warming studies

Diode laser measurements of CO line widths at planetary atmospheric temperatures

Measurements of line intensities and line widths in the ν3-fundamental band of nitrous oxide at atmospheric temperatures