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  • A more consistent formulation of boundary layer turbulence, shallow convection and sub-grid cloud including:

    • Simplified and more consistent treatment of sub-grid cloud saturation adjustment,

    • Consistent treatment of subgrid cloud from boundary layer turbulent mixing without separate statistical cloud scheme,

    • Consistent computation of mixing height for unstable turbulent boundary layer and convection scheme,

    • Change from double to single iteration of turbulent mixing scheme;

  • New method for computing inversion strength based on moist entropy for distinguishing stratocumulus and cumulus cloud;

  • Limit to convective overshoot based on tropopause stability;

  • New parametrized deep convection closure with an additional dependence on total advective moisture convergence;

  • Change from exponential-exponential cloud vertical overlap to random-exponential overlap in closer agreement with observations;

  • Include vapour deposition process for growth of falling snow particles;

  • Change from linear to cubic interpolation for cloud liquid, ice, rain and snow semi-Lagrangian departure point calculations, including 3D quasi-monotone limiter;

  • Interpolation of cloud and precipitation to radiation grid changed from in-cloud to grid-mean;

  • Inclusion of full supersaturation adjustment in the ensemble SPPT stochastic perturbations;

  • Mass-weighting and relaxation timescale introduced for ensemble SPPT stochastic perturbations;

  • Bug fix for vertical interpolation of 3D aerosol climatology;

  • Improved calculation of extinction coefficients for near-surface visibility in fog, rain and snow;

  • Revised gustiness parametrization;

  • Improved calculation of the peak wave period for multi-peaked ocean wave spectra.

48r1 – Multi-layer snow, climate fields, water and energy conservation, interactive ozone, freezing drizzle

  • Multi-layer snow scheme;

  • Revised climate fields – improved orographic fields for atmospheric drag;

  • Improved water and energy conservation (dynamics and physics);

  • Radiatively interactive prognostic ozone using new Hybrid-Linear Ozone (HLO) scheme;

  • New precipitation category - freezing drizzle and revised microphysical processes;

  • Revised computation of Semi-Lagrangian advection departure points;

  • New model top sponge layer formulation and semi-Lagrangian vertical filter;

  • Revised SPPT, removed cloud saturation adjustment from tendency perturbations.


Summary of technical changes compared to OpenIFS 43r3v2

  • OpenIFS 48r1 ECbuild/cmake build system
    • the build system has been changed from FCM to ECbuild/cmake. This change means that 
      • OpenIFS uses the same build system as the IFS and can therefore capitalise on the pre-existing build options such as enablling single and/or double precision 
      • Simplifies the creation of OpenIFS from IFS
    • Associated changes in OpenIFS build scripts, please see Build OpenIFS 48r1
  • OpenIFS 48r1 can be built using single and/or double precision
  • OpenIFS includes CAMS chemistry and aerosol as implemented in the corresponding IFS cycle, i.e. 48r1, by default
    • Thus, as well as an upgrade, this release consolidates OpenIFS and OpenIFS/AC into one single code base, with one development workflow.
    • More aligned with the IFS
  • OpenIFS 48r1 includes the single column model (SCM) and builds the SCM alongside the 3-D model by default
  • OpenIFS 48r1 includes ifs-test with
    • 21 t21 tests of forecast-only functionality with and without chemistry
    • 1 SCM test
    • ifs-test can be used to
      • validate the installation, i.e., validate the build and basic simulation capability
      • genarate "known good output" for a given system and compiler, which can be used to test any code changes

Experiment data and namelist changes

There have been a significant number of changes to the model namelists and initial data format compared to OpenIFS 43r3. It is recommended that users do not attempt to use OpenIFS 43r3 namelists with OpenIFS 48r1 but should obtain new experiment data and matching namelists suitable for model cycle 48r1.

The recommended way to obtain initial experiment data for forecast experiments with OpenIFS is to use the OpenIFS Data Hub. For any data requests that are currently not served by the Data Hub please contact OpenIFS support by emailing openifs-support@ecmwf.int.