Dear Colleagues, you receive this eMail because you are either a user of the radiative transfer package libRadtran or because we think that you might be interested in this information. Should you not be interested in receiving further information, please let us know! Attached to this eMail is the 11th libRadtran Newsletter. The main issue of this Newsletter is to announce the new version, *** libRadtran 1.5-beta *** which includes some bug fixes and several improvements compared to version 1.4 Have fun! Bernhard Mayer, Claudia Emde, Robert Buras, Ulrich Hamann, and Arve Kylling. ------------------------------------------------------------------ Prof. Dr. Bernhard Mayer Bernhard.Mayer@dlr.de Lehrstuhl fuer Experimentelle Meteorologie Ludwig-Maximilians-Universitaet Theresienstrasse 37, 80333 Muenchen Phone: +49 89 21804383, Fax: +49 89 2805508 also at: DLR Oberpfaffenhofen, Inst. fuer Physik der Atmosphaere Phone: +49 8153 282568, Fax: +49 8153 281841, Homepage: http://www.bmayer.de ------------------------------------------------------------------ /*---------------------------------------------------------------- * libRadtran Newsletter No. 11 * * February 2, 2010 * * Bernhard Mayer (bernhard.mayer_at_lmu.de) * Claudia Emde (claudia.emde_at_lmu.de) * Robert Buras (robert.buras_at_lmu.de) * Ulrich Hamann (ulrich.hamann_at_dlr.de) * Arve Kylling (arve.kylling_at_gmail.com) * * ### More info: http://www.libradtran.org ### *----------------------------------------------------------------*/ Dear libRadtran users, Phil says "six more weeks of winter" (http://www.groundhog.org/). Same here in Germany: "Wenn's an Lichtmess stuermt und schneit, ist der Fruehling nicht mehr weit; ist es aber klar und hell, kommt der Lenz wohl nicht so schnell." - since it was nice and clear here today, stay tuned for another 6 weeks of winter. In the meantime, try the new libRadtran release! And now for the changes of version 1.5-beta compared to 1.4: *** Major changes: * You might notice the beta in the version number. This has to do with the huge number of changes and new features introduced which will certainly need more testing. We count on your help! * disort2 was modified to directly use the scattering phase function rather than its Legendre moments. The model output isn't sigificantly affected - if anything it should be slightly more accurate. The huge advantage, however, is the considerable reduction of memory consumption and computational speed (it takes more than 10000 Legendre moments for an ice cloud phase function in the shortwave but only around 600 grid points are required to tabulate the phase function). For those of you familiar with disort2: The radiative transfer calculation is still done with the first nstr Legendre moments, but for the Nakajima intensity correction the phase function is used instead. The implementation is rather tricky, but hopefully you won't notice any difference, except that the optical property files are much smaller now (actually, they are not because the space saved by the change above has been used to increase the number of wavelength grid points). The old, unmodified disort2 is also stillavailable as "rte_solver disort2_original" * As a consequence of the above change, the optical property files (in data/wc, data/ic, data/aerosol) have been updated for the new format. A much better wavelength resolution is now possible e.g. for "wc_properties mie". You may obtain them from the libRadtran Downloads page (careful: more than 1 GByte data!) * Polarization is finally fully included (that is, all the optical properties including water and ice clouds are available now for polarization calculations). However, please be aware that our current implementation of the polRadtran solver is not appropriate for calculating radiances for strongly peaked phase functions. We are looking for a solution to allow better calculations of polarized radiances in cloudy atmospheres. * First order rotational Raman scattering may be included in spectral calculation by the 'raman' option. Raman scattering is treated as a perturbation similar to the approaches of Vountas et al. (1998) and Spurr et al. (2008). A special radiative transfer solver, qdisort, is needed to solve the radiative transfer equation including Raman scattering. The qdisort solver is based on the pseudo-spherical sdisort solver. The 'raman' option has been extensively tested and verified. However, it is a new option and should be used with care. Also it is not optimized for speed. It is thus computationally expensive. Major improvements in speed are planned for future releases. * A first version of a graphical user interface (GUI) has been included. This tool is still far from complete but it might already be very helpful for users to create input files. In order to try the GUI, go to the GUI directory and run 'python GUI.py'. For the GUI to run properly you need - to install python and wxPython (don't complain! python doesn't cost anything and it is very useful) - to set the libRadtran data path (LIBRADTRAN_DATA_FILES) - to include uvspec in your binary path ** Smaller changes: * Several smaller bug fixes. * Bug fix: When the Kato/Kato2 k-distribution was chosen, functions such as h2o_mixing_ratio and co2_mixing_ratio did not have any effect on the results. We apologize for that one! The latest version is available at http://www.libradtran.org, as usual. And now, have fun! * Bernhard Mayer (bernhard.mayer_at_lmu.de) * Claudia Emde (claudia.emde_at_lmu.de) * Robert Buras (robert.buras_at_lmu.de) * Ulrich Hamann (ulrich.hamann_at_dlr.de) * Arve Kylling (arve.kylling_at_gmail.com)