RTTOV Overview

Please note that resources and documentation for older versions of RTTOV can be found on the archived old site.

Introduction

Current version: v11.3, September 2015

RTTOV (Radiative Transfer for TOVS) is a very fast radiative transfer model for passive visible, infrared and microwave downward-viewing satellite radiometers, spectrometers and interferometers. It is a FORTRAN 90 code for simulating satellite radiances, designed to be incorporated within user applications.

Given an atmospheric profile of temperature, water vapour and, optionally, trace gases, aerosols and hydrometeors, together with surface parameters and a viewing geometry, RTTOV will compute the top of atmosphere radiances in each of the channels of the sensor being simulated.

In addition, RTTOV also optionally computes the Jacobian matrix which describes the change in radiance for a change in any element of the state vector assuming a linear relationship about a given atmospheric state. For a brief mathematical overview of radiative transfer modelling see this page.

The most recent version of RTTOV is v11.3, released in September 2015.

Some example applications of using RTTOV software are given on the RTTOV applications page.

Obtaining RTTOV

RTTOV is available to licensed users free of charge. To become a licensed user of RTTOV, please register with the NWP SAF (or login if you have already done so) and add RTTOV to your list of software preferences. Older versions of RTTOV are available to download to maintain compatibility with certain software but are not supported by the NWP SAF.

It is recommended (though not mandatory) to compile RTTOV against the HDF5 library (v1.8.8 or later required). This enables the use of HDF5 format coefficient files (the preferred format for hyperspectral sounders), the land surface emissivity and BRDF atlases, the Python and C++ interface to RTTOV and the RTTOV GUI.

If you do not compile against the HDF5 library you can still use the land surface emissivity and BRDF atlases and the Python/C++ interface if you compile RTTOV against the netCDF library (v3.6 or later).

In order to compile the RTTOV GUI or to call RTTOV from Python scripts you must also have F2PY (part of NumPy ) installed.

The GUI has additional requirements which are given in the GUI users’ guide.

Documentation and Resources

Instructions for compiling and running the most recent version of RTTOV may be found here. The User Guide also contains comprehensive details of the new features in RTTOV v11 and the changes from RTTOV v10. Further documentation, including the RTTOV ‘Science and validation report’ can be found on the RTTOV 11 homepage.

Resources (coefficients, atlases, etc.) compatible with RTTOV v11 can be accessed on the downloads page.

Details of future development planned for RTTOV can be found on the Future Plans page. Users wishing to make suggestions for new features should contact the helpdesk.