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Overview

OpenIFS 48r1 is based on the ECMWF operational IFS cycle 48r1 which has been the ECMWF operational model since June 27th 2023 (see Model upgrade increases skill and unifies medium-range resolutions)

OpenIFS 48r1 is a significant scientific and technical upgrade from the previous OpenIFS 43r3v2 model release and includes, amongst other things, a moist physics upgrade, incorporation of multi-layer snow scheme,  inclusion of operational CAMS chemistry and many more updates to the model physics parametrizations. Technical upgrades includes a new build system (move from FCM to ecbuild/cmake), major restructure of the code, inclusion of the single column model (SCM) and inclusion of ifs-test

Anyone wishing to use OpenIFS must have a OpenIFS license (see the list of Licensed Institutes).

It is important to note that OpenIFS 48r1 will not produce the same results as the previous releases based on 43r3.

Support

Please report any issues or problems with this release to either the OpenIFS User Forums or openifs-support@ecmwf.int.

Model Documentation 

OpenIFS 48r1 is scientifically identical to the forecast model of IFS 48r1. For a full description of the IFS 48r1 operational model, please see IFS documentation, noting that Part I and II and any sections on Observations and Data Assimilation are not applicable to OpenIFS. 

Summary of scientific changes compared to OpenIFS 43r3v2

Changes to the operational IFS can be found on the website (search for “ECMWF IFS changes”)

https://www.ecmwf.int/en/forecasts/documentation-and-support/changes-ecmwf-model

45r1 – Cloud microphysics, soil physics

• Improved numerics for warm-rain cloud microphysics and vertical extrapolation for semi-lagrangian trajectory;

• Increased methane oxidation rate to improve (increase) water vapour in the stratosphere;

• Improved representation of super-cooled liquid water in convection, and minor convection updates;

• Correction of soil thermal conductivity formulation and addition of soil ice dependency;

• Modified parameter for non-orographic gravity-wave drag scheme for 91 levels.

46r1 – Radiation and aerosol, convection 

• Improvements in convection scheme (entrainment, CAPE closure, shallow convection);

• Activate LW scattering in radiation scheme;

• 3D aerosol climatology replaces 2D climatology;

• Correct scaling of dry mass flux in diffusion scheme. 

47r1 – Albedo, ocean waves drag, quintic interpolation 

• Surface albedo changes including: 1) the use of six climatological fields from MODIS, 2) a better handling of the spectrum from the MODIS datasets;

• Total Solar Irradiance (TSI) and Green House Gases (GHG) timeseries are updated with more recent ones from CMIP6;

• Quintic interpolation in the vertical for semi-Lagrangian advection;

• The drag coefficient over the oceans is reduced for strong winds to account for observational evidences whereby the drag coefficient reduces sharply for high winds;

• Stability corrections to the mid-level and deep convective closures (neutral) and reduced bounds for parcel perturbations.