Cycle 40r1v1

IFS cycle 40r1 was the operational model at ECMWF from 19th November 2013 to 12th May 2015.

Several significant changes have been made since the previous release, particularly with regard to convection where the diurnal cycle is much improved (see ECMWF Newsletter 136 - pages 15-22).

For more information on the IFS 40r1 release, see the description of the IFS 40r1 cycle, more detailed summary of changes in IFS cycle 40r1 is also available.

Please note these changes are relative to the previous operational model. As OpenIFS models are not released as frequently as the operational model, interested users should also see the changes between all IFS operational cycles 40r1 and 38r1.

Model documentation

The IFS cycle 40r1 model documentation (PDF manuals) is available from the main ECMWF website.

Brief summary of changes:

91 -> 137 vertical levels.
OpenIFS 40r1 now includes ECMWF wave model.
Reduced vertical resolution dependence in the subgrid orography scheme.
Bugfix for the spectral-band split of the albedo in the radiation.
Modified treatment of turbulent diffusion in stable conditions (implying a reduction of the diffusion).
Adjustment of the drag over orography and the low level blocking.
Adjustment of the land-atmosphere coupling for high vegetation.
Modification of the PBL height diagnostic according to the findings of Seidel et al. 2012.
Diurnal cycle extension of CAPE for land and water that significantly improves diurnal variation of convection.
Formulate CAPE in J/V instead of J/kg from which mass flux follows naturally.
New interface to the physics.
Support for the PGI compiler has been withdrawn.
Support for GNU compiler version 6 added.

Note some features from Fortran 2003 are now used, that may require more recent versions of compilers (allowing support of the ASSOCIATE construct). We also do not recommend version 15 of the Intel compiler which has known issues with the OpenIFS code.

Grib-api

Please note that the minimum version of grib-api for use with Cycle 40r1 is 1.11.0.
If you see the following error when compiling, please upgrade your version of grib-api:

Error: There is no specific subroutine for the generic 'grib_write_bytes'

OpenIFS 40r1v1 does not currently support the ECMWF ecCodes library: the replacement library for grib_api. Please continue to use grib_api. If this is not possible, contact openifs-support@ecmwf.int.

Namelist changes

Some namelists and namelist variables have changed. For more details please see the model code.

A key change is:

LFPOS=.T. should be replaced by the new variable NFPOS=2,

Acknowledgements

The OpenIFS team would like to acknowledge the research and support of ECMWF scientists involved in this release.