HITRANonline: A NEW STRUCTURE AND INTERFACE FOR HITRAN LINE LISTS AND CROSS SECTIONS

We present textbf{HITRAN}emph{online}, an online interface to the internationally-recognised HITRAN molecular spectroscopic database[1], and describe the structure of its relational database backend[2]. As the amount and complexity of spectroscopic data on molecules used in atmospheric modelling has increased, the existing 160-character, text-based format has become inadequate for its description. For example, line shapes such as the Hartmann-Tran profile[3] require up to six parameters for their full description (each with uncertainties and references), data is available on line-broadening by species other than ``air'' and ``self'' and more than the current maximum of 10 isotopologues of some molecules (for example, $mathrm{CO_2}$) can be important for accurate radiative-transfer modelling. The new relational database structure overcomes all of these limitations as well as allowing for better data provenance through ``timestamping'' of transitions and a direct link between items of data and their literature sources. To take full advantage of this new database structure, the online interface textbf{HITRAN}emph{online}, available at www.hitran.org, provides a user-friendly way to make queries of HITRAN data with the option of returning it in a customizable format with user-defined fields and precisions. Binary formats such as HDF-5 are also supported. In addition to the data, each query also produces its own bibliography (in HTML and BibTeX formats), ``README'' documentation and interactive graph for easy visualization. {footnotesize begin{enumerate} item L. S. Rothman emph{et al.}, emph{JSQRT} textbf{130}, 4-50 (2013). item C. Hill, I. E. Gordon, L. S. Rothman, J. Tennyson, emph{JQSRT}textbf{130}, 51-61 (2013). item N. H. Ngo, D. Lisak, H. Tran, J.-M. Hartmann, emph{JQSRT} textbf{129}, 89--100, (2013); erratum: emph{JQSRT} textbf{134}, 105 (2014). end{enumerate} } This work has been supported by NASA Aura Science Team Grant NNX14AI55G and NASA Planetary Atmospheres Grant NNX13AI59G