Future Plans

Future Plans

We welcome suggestions for new or updated capabilities via the NWP SAF Helpdesk. Summaries of results from RTTOV user surveys is available on the documentation page.

The plans outlined below may be subject to change in light of newly identified user requirements.

Nominal release schedule:
RTTOV v14.0 – January 2025 (more details available here)
RTTOV v14.1 – ~November 2025
RTTOV v14.2 – ~July 2026
RTTOV v15.0 – September 2027

Developments planned or under consideration for future RTTOV releases include:

  • Improvements to UV simulation capability (v14.x)
  • MFASIS-NN aerosol simulation capability (v14.1)
  • Implement alternative (more efficient) cloud overlap option(s) for visible/IR scattering simulations (v14.1)
  • Updated BRDF atlas based on MODIS Collection 6 (v14.1)
  • Further improvements to MFASIS-NN cloud simulation accuracy (v14.2)
  • Further improvements to improve spectral consistency in scattering simulations (v14.x)
  • Investigate further improvements to the gas optical depth parameterisation based on v13 predictors including eliminating negative optical depths in the regression (v14.x)
  • Investigate inclusion of 3D effects in MW, visible and IR scattering simulations
  • Investigate parameterisation of aerosol optical properties in terms of particle size
  • Improved tools for generating scattering property files for use with RTTOV at all wavelengths
  • Add CMake support for building RTTOV.
  • Investigate compiling/running RTTOV on GPU architectures.
  • ** Consider removal of PC-RTTOV capability unless strong user requirements are identified (v15) **

On-going general developments

  • Keep up to date with latest spectroscopy and LBL models
  • Updates to the RTTOV GUI to support new capabilities
  • Updates to the Python/C++ wrapper to support new capabilities
  • Code optimisation to increase speed and reduce memory usage

We have had requests for the following capabilities/updates, but we currently do not plan to implement them for reasons of complexity and/or prioritisation of resources:

Making coefficient generation software available to users
This software is complex and would require considerable resources to support users in running it which we feel would be better spent developing RTTOV itself. We also prefer to be able to retain control over the official RTTOV coefficients that are available in order to maintain consistent quality among them. The NWP SAF is responsive to all user requests for new coefficients. This includes coefficients for theoretical instruments which may involve multiple variations of channel specifications: we are actively supporting a number of users in this regard currently.

Simulation of ground-based sensors
Clear-sky simulations of ground-based MW sensors are possible using the RTTOV-gb package. The NWP SAF does not develop or maintain this package. We do not have the resources to develop this capability further.

Simulation of airborne sensors
This was investigated and proved to be impractical with the current optical depth parameterisation used by RTTOV. This could be revisited in the future if an alternative optical depth parameterisation is implemented.

Implement RTTOV wrapper for language X
Currently the wrapper allows much RTTOV capability (direct and Jacobian model clear-sky and scattering simulations including use of land surface emissivity/BRDF atlases) to be called from C, C++ or Python code. The current wrapper capability will be maintained in future versions and will be extended to support new RTTOV capabilities. However the implementation of the wrapper for a given language requires a significant development effort with additional effort required for maintenance as RTTOV develops. Therefore we do not plan to support additional languages in the wrapper.

Support for the RTTOV TL/AD models in the Python/C++ wrapper
These would require considerable development effort to implement and maintain. If required the TL and AD can be computed from the Jacobian (K) model wrapper, though this is less efficient than computing them directly.