The Met Office 1D-Var package is a stand-alone system for doing 1D-Var retrievals with user-provided files of observation and background error covariances. The package is configured to support ATOVS, AIRS and IASI sensors, and is capable of supporting any nadir-sounding sensor for which a suitable radiative transfer model is available. The code is written in Fortran-90, using many of the intrinsic features. It is tailored to be flexible for research purposes and for portability rather than being streamlined for operational running within an NWP model. Users who require the code to run efficiently within their NWP system should expect to do some optimisation of the code for their platform.

Version 3.2 of the Met Office 1D-Var was released in May 2007 and is available to licensed users free of charge.

Version 3.2 adds support for the RTTOV-8 radiative transfer model. To become a licensed user of the Met Office 1D-Var code v3.2, please send a request using the Met Office 1D-Var Request Form.

Please note that the radiative transfer model RTTOV is required for most applications of the Met Office 1D-Var. RTTOV is available from the NWP SAF, also free of charge, under a separate licence.

• Further information
  • Overview of the NWP SAF 1D-Var packages (PDF)

• Met Office 1D-Var:

• Product specification (PDF)
• Top-level design (PDF)
• Portability guide (PDF)
• User’s Guide

• Bug reports and fixes