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. Should you know of anybody who might be interested in libRadtran and whose name is not on the distribution list, please let us also know as well. Attached to this eMail is the second libRadtran Newsletter. The main issue of this Newsletter is to announce the new version, *** libRadtran 1.0-beta *** And now, we wish you all a merry christmas and a happy and successful new year! Bernhard Mayer and Arve Kylling. ------------------------------------------------------------------ Dr. Bernhard Mayer Bernhard.Mayer_at_dlr.de Deutsches Zentrum fuer Luft- und Raumfahrt (DLR) Institut fuer Physik der Atmosphaere, Oberpfaffenhofen, D-82234 Wessling, Germany. Phone: +49 8153 282568, Fax: +49 8153 281841, Homepage: http://www.bmayer.de ------------------------------------------------------------------ /*---------------------------------------------------------------- * libRadtran Newsletter No. 2 * * December 23, 2002 * * Bernhard Mayer (bernhard.mayer_at_dlr.de) * Arve Kylling (arve.kylling_at_nilu.no) * * ### More info: http://www.libradtran.org ### *----------------------------------------------------------------*/ Welcome to the second libRadtran Newsletter! The main issue of this Newsletter is the announcement of *** libRadtran 1.0-beta *** Since the release of version 0.99 in December 2001, many new options have been added. After about 10 years development of uvspec and libRadtran we decided that the current version is complete and self-consistent enough to be called 1.0. A "beta" was added because introducing new features often implies the introduction of more bugs. Please be warned that the new release 1.0-beta is likely to have more bugs than the last stable release, 0.99. The new features have been tested to some degree, but with the available number of input options it is nearly impossible to test all possible combinations of input options. Here we need the help of all users: If you find a bug, please send us a message including all the relevant information. This will help to further improve libRadtran. *** Features of version 1.0-beta compared to 0.99 *** - General: o First of all it is important to note that, although some small inconsistencies were fixed, no major bugs were found. Hence, the output from 1.0-beta should be within 1% or less of the 0.99 output, with very few exceptions. o The vertical grids of molecules (atmosphere_file), aerosols, water and ice clouds are now completely independent (previously all components had to be defined on the same vertical grid). Now it is possible to use e.g. one of the standard atmospheric profiles together with the following water cloud file (wc_file) 3.2 0.0 10.0 2.2 0.1 10.0 If wc_layer was set as well, this data would be interpreted as a homogeneous cloud between 2.2 and 3.2 km. The difference to the previous version is: - The cloudless layers don't need to be explicitely listed (except for the 3.2km level in this example which defines cloud top) - The atmospheric data are now automatically interpolated to the cloud layers defined here. The same is true for aerosols and ice clouds. *** To make sure that uvspec really does what you want it to *** *** do it is recommended to always do a monochromatic test *** *** run with 'verbose' switched on *** o The gas absorption parameterization from SBDART has been included and can be invoked with 'correlated_k SBDART'. This allows pseudo-spectral calculations throughout the complete solar and thermal spectral ranges. Please read the section on "Spectral resolution" in the libRadtran manual. o The manual has been improved considerably. In particular, a chapter about "Spectral resolution" has been added which explains in detail the different ways to do spectral calculations in uvspec. The manual is now provided as pdf rather than Postscript. libRadtran.pdf is now the user manual while libRadtran_developer.pdf contains some more information about some of the library functions provided with libRadtran (you won't usually need the latter). - Molecular absorption: o New option 'rh_file' to define a profile of relative humidity which defines the water vapour concentration and affects the aerosol o Added NO2 absorption; the column may be either set with no2_column_du [DU] or no2_column_moleccm-2 [molec cm-2] o Added OClO and OBrO absorption; o Added a new and much simpler way to define columns and profiles of several absorbers (O3, NO2, H2O, BrO, OClO, CO2), 'dens_column' and 'dens_file'. - Aerosol: two minor fixes o Better treatment of 'aerosol_visibility': aerosol optical thickness and visibility are now treated consistently which they were not when unreasonable combinations of 'aerosol_visibility' and the optical thickness were chosen (e.g. the default visibility of 50km and an optical thickness of 2). o Changed aerosol vertical profile interpolation from logarithmic to linear which allows a more consistent altitude profile calculation. - Several new options to process the output: 'output sum' sums the output over wavelength; very useful e.g. in combination with 'correlated_k ...' o 'filter_function_file' allows the user to define a wavelength-dependent filter function which is applied to the output data. o 'reflectivity' calculates real reflectivities; check documentation of 'reflectivity' and 'transmittance' o 'brightness' calculates brightness temperatures instead of radiances and fluxes. - Added ocean surface BRDF parameterization; Cox and Munk, taken from Seiji Kato's well-tested routine. New uvspec input parameters are 'cox_and_munk_u10' (wind speed), 'cox_and_munk_pcl' (pigment concentration), and 'cox_and_munk_sal' (salinity) Does only work with 'rte_solver DISORT2' - More intelligent handling of wavelength ranges: If transmittance_wl_file or correlated_k are specified, wvn may be omitted - RTE solvers: The parameters to adjust the compile-time parameters of all DISORT variants are now to be found in one single file, src_f/DISORT.MXD, rather than several files. - Added 'include' option to include files into the uvspec input - More examples - Many many small changes and new input options which are not discussed here in detail. The latest version is available at http://www.libradtran.org, as usual. And now, have fun! Bernhard Mayer (bernhard.mayer_at_dlr.de) Arve Kylling (arve.kylling_at_nilu.no)