SPECTRA, an Internet Accessible Information System for Spectroscopy of Atmospheric Gases Semen MIKHAILENKO, Yurii BABIKOV, Vladimir GOLOVKO, and Sergei TASHKUN Laboratory of Theoretical Spectroscopy, Institute of Atmospheric Optics, 1, av. Akademicheskii, Tomsk, Russia System structure The system is a software tool to search and retrieve some information from database, process it and display the results in graphical and/or numerical forms. The architecture of this tool is traditional for the software of this type and includes the main code, library of classes and routines, and the database. Description of all three parts of the system is given in Refs. [1, 2]. The main code processed the user’s requests and displayed the results in graphical and text forms. Library of classes and routines consists of three parts: the computational modules library (C++ and Fortran languages), PHP classes library [3], the service library (PHP language [4]). The database operates under the DBMS MySQL [5] and includes two parts: a subject oriented database and a database of administrative information. The content of database is described in Ref. [1]. Goal The main goal of SPECTRA is to provide an access via Internet to spectroscopic information of atmospheric molecules and to perform some spectroscopic calculations interactively. Among the problems that can be solved are: retrieval, extraction, and visualization of spectroscopic data ; simulation and visualization of high and low resolution spectra ; calculations with user defined gas mixtures ; calculations of line positions and intensities by the effective operator method ; download of the results to the user’s computer and/or saving these results in the system. All results can be displayed in graphical and numerical forms as well as downloaded on the user’s computer by request. Home page of the system and a window of the help subsystem are shown on Figure 1. Figure 1. Home page of the system (on the left), window of the help system (on the right). Main Options Access to line-by-line spectroscopic parameters of rotation-vibration transitions of 45 molecules in the 0 – cm -1 spectral range Calculation of spectrum functions (stick-diagram, absorption coefficient, transmission, emission, absorption) as a function of the wavenumber for selected Molecule / Isotopic species / Band(s) Calculation of absorption, transmission or emission spectra for selected Gas Mixture and Spectral Region Preparation of gas mixtures (for registered users only) Convolution of high resolution spectra with different apparatus functions Visualization of the request results in graphical and numerical forms Downloading of the results to a user’s computer Saving data in the user’s directory on the server (for registered users only) Creation of the personal sets of spectra and gas mixtures (for registered users only) Downloading of the user spectra on the server (for registered users only) Manipulation with saved data (for registered users only) Spectrum simulation using selected Hamiltonian and dipole transition parameters for ozone and water molecules Detailed description of the SPECTRA system options is given in Refs. [2, 12]. Some examples of the different system options are given on figures below. Sectroscopic databases SPECTRA provides an access to the following spectroscopic databases (line-by-line lists, cross sections, etc.): a). Well known databanks - HITRAN-2006 (including updates 2007 and 2008), ftp://cfa-ftp.harvard.edu/pub/HITRAN/ - HITEMP, ftp://cfa-ftp.harvard.edu/pub/HITRAN/ - GEISA-2003, ftp://ara01.lmd.polytechnique.fr b). Original data sets developed in the Institute of Atmospheric Optics - CDSD, carbon dioxide spectroscopic databank for atmospheric and high temperature applications [6, 7], accessible also on ftp://ftp.iao.ru/pub/CDSD and on - PS-2007, calculated linelists for 9 isotopic species of the water molecule. All calculations have been done by Dr. S.A. Tashkun using the VTET computer code [8] developed by Dr. D.W. Schwenke, a potential energy surface [9] and a dipole moment surface [10]. - IAO, compilation on infrared spectra of three isotopic species of hydrogen sulfide has been done by Dr. O.V. Naumenko. Examples of all spectroscopic databases are given on Figure 2. The system is enhanced by experimental spectra of 34 molecules. This information can be obtained in the “Cross-Sections” section. of 34 molecules. References 1. Yu.L. Babikov, A. Barbe, V.F. Golovko, S.N. Mikhailenko, and Vl.G. Tyuterev, in: Proceedings of the 3 rd All-Russian Conference on Electronic Libraries: Perspective Methods and Technologies, Electronic Collections. Petrozavodsk, pp (2001) 2. S.N. Mikhailenko, Yu.L. Babikov, and V.F. Golovko, Atmospheric & Oceanic Optics, 18, (2005) S.A. Tashkun, V.I. Perevalov, J.-L. Teffo, A.D. Bykov, and N.N. Lavrentieva, in Proceedings of the NATO Advanced Research Workshop on Remote Sensing of the Atmosphere for Environmental Security, Rabat, pp (2006) 7. S.A. Tashkun, V.I. Perevalov, J.-L. Teffo, A.D. Bykov, and N.N. Lavrentieva, JQSRT, 82, (2003) 8. D.W. Schwenke, J. Phys. Chem. 100, 2887 (1996) 9. H. Partridge and D.W. Schwenke, J. Chem. Phys. 106, (1997) 10. D.W. Schwenke and H. Partridge, J. Chem. Phys. 113, (2000) 11. O.V. Naumenko and E.R. Polovtseva, Atmospheric & Oceanic Optics, т.16, с (2003) 12. S.N. Mikhailenko, S.A. Tashkun, Yu.L. Babikov, and V.F. Golovko, Atmospheric & Oceanic Optics, 17, (2004) 13. S.A. Tashkun and Vl.G. Tyuterev, Proceedings of SPIE, 2205, (1994) Figure 4. Examples of gas mixture (on the left) and mixture of isotopic species preparation (in the centre and on the right) Line positions and intensities calculation The GIP code [13] has been developed as a tool for calculation and data fitting of rotation-vibration line positions and intensities for H 2 O, O 3, H 2 S, SO 2 and some other triatomic molecules using the effective Hamiltonian approach. This code has been integrated in SPECTRA for giving a possibility to users calculate rovibrational spectrum for selected bands of ozone and water. Detailed description of this option is given in Ref. [12]. Figure 2. Examples of data sources for the water (on the left), carbon dioxide (in the centre) and hydrogen sulfide (on the right) Figure 5. List of available dipole moment parameters for the ozone molecule (on the left), the task menu for spectra simulation (in the centre) and calculated spectrum in graphical form (on the right) The “Gas mixture spectra” section provides a tool for simulating spectra of a selected gas mixture within the specified spectral interval. User can select spectrum type, gas mixture, line shape and apparatus function using pull-down menus in the request form. Upon input editing of general and contour parameters push the button “Simulate spectrum”. The computed spectrum will be shown on the page “Simulation”. To obtain calculated spectrum in text format user must push on the button “Show”. Figure 3. Examples of the request form for the spectra simulation and results of calculations Figure 6. Examples of the spectroscopic data extraction. The list of 16 O 13 C 32 S bands (on the left) and the stick-diagram of the ozone bands between 2900 and 4850 cm -1 (in the centre) in the HITRAN database. Calculated spectrum of the H 2 32 S molecule in the 6000 – 6600 cm -1 region using the IAO database (on the right)