What is RTTOV? A brief explanation can be seen here.
Questions for other users and developers can be posted on the RTTOV Forum.
Version 11.3 of RTTOV was released in September 2015. RTTOV is available to licensed users free of charge. To become a licensed user of RTTOV v11, please send a request using the RTTOV v11 Request Form. Note that it is assumed that you have experience of running Fortran 90 code under Linux or UNIX and knowledge of basic radiative transfer theory. A list of requirements for running RTTOV can be found here.
RTTOV code updates, documentation, updated coefficient files and bug reports (click on model version you require)here.