OpenIFS reference pages

# OpenIFS reference case studies

Two weather events have been chosen to show the OpenIFS model capabilities and to provide reference cases for the users. Numerous model experiments have been achieved; their input data, namelists as well as the reference (re-analysis) data and the output figures can be downloaded from this page.

## Case studies

Storm events with severe impact over Europe and governed by large-scale dynamics have been selected.

Storm Xaver hit the North Sea region and several adjacent countries on 5 December 2013. The cyclone developed around 00 UTC on 4 December northeast of Newfoundland and it was situated between converging northerly and southerly airstreams. Problems were caused by the high wind speeds and the related storm surge. The operational forecast was skillful: the cyclone presented in the forecasts 8-9 days before the event and the forecasts indicated the very strong wind gust 3-4 days in advance.

Storm Desmond caused severe flooding, travel disruption and a power outage across northern England, parts of Scotland and Ireland on 5 December 2015. It broke the United Kingdom's 24-hour rainfall record. Orographical precipitation enhancement played a major role in the event. The forecast skill of the ECMWF operational model was weak: although it picked well the highest rainfall amounts over the orographical barriers, the forecast underestimated the peak precipitation values and overestimated the precipitation amount in lee of the hills.

Several experiments have been conducted with OpenIFS for these two cases with the aim to test the effect of different starting dates and forecast lengths, initial conditions as well as spatial resolutions to the forecast quality. The experiment details are summarized in the Meteorological Evaluation part of the OpenIFS home page.

## Input data

The input data (consisting of initial conditions and namelists) are packed in .tar.gz files and structured into directories named after the case studies (i.e., Xaver_201312, Desmond_201512) and subdirectories indicating the main experiment characteristics (e.g., T255L91_ERA5). Separate archive files were prepared for the different starting dates (e.g., gs0c_2015120300.tar.gz).

ERA-Interim and ERA5 re-analyses are used as reference for evaluation of the experiment results. The data are available for some meteorological variables in GRIB format in the input package. They are located in .tar.gz files in the reference folder, the filenames (e.g., ei_20151201-20151206.tar.gz) indicate the data source (ei for ERA-Interim and ea for ERA5) and the covered time period.

The requested archives can be downloaded by clicking on them one by one in the corresponding folders:

Retrieval of the complete package is also possible using wget (wget builds up the same directory structure as in the ftp site):

document.write("% INPUTDIR=" +location.href.replace(/[^/]*$/, '')) % wget -c -r -l2 --no-parent -A.gz${INPUTDIR}data/Xaver_201312     # to download all data for Xaver
% wget -c -r -l2 --no-parent -A.gz ${INPUTDIR}data/Desmond_201512 # to download all data for Desmond % wget -c -r -l3 --no-parent -A.gz${INPUTDIR}data                  # to download all data

The md5sum.out file is provided to check the download. The file also has to be retrieved and then the downloaded data can be compared against it:

% md5sum -c md5sum.out

If the download is not complete, the following (exemplary) warning message can be given:

% md5sum -c md5sum.out
T255L91_ERAI/gryg_2015120100.tar.gz: OK
T255L91_ERAI/gryg_2015120200.tar.gz: OK
T255L91_ERAI/gryg_2015120300.tar.gz: OK
T255L91_ERAI/gryg_2015120400.tar.gz: OK
T255L91_ERAI/gryg_2015120500.tar.gz: OK
...
md5sum: T1279L137_ERAI/gs23_2015120300.tar.gz: No such file or directory
md5sum: WARNING: 1 listed file could not be read

The retrieved .tar.gz files have to be uncompressed (the filename can be different):

% tar zxf gryg_2015120300.tar.gz

An example for content of the experiment archive files (dates and sizes are different for the different cases and resolutions):

File name   Description Size
2015120300/ : directory for a given starting date 0 MB
2015120300/ecmwf/ : subdirectory containing the namelists and some outputs 0 MB
2015120300/ecmwf/namelistfc : namelist with detailed experiment setup 4.6 KB
2015120300/ecmwf/NODE.001_01.model.1* : text output (log) file including all the important information about the model run 3.8 MB
2015120300/ecmwf/ifs.stat.model.1* : information about model steps (useful for debugging) 26 KB
2015120300/ecmwf/wam_namelist : namelist of the coupled wave model 3.1 KB
2015120300/ICMCLgs0cINIT : input file containing surface and soil information (albedo, soil temperature etc.) 9.3 MB
2015120300/ICMGGgs0cINIT : input file containing gridpoint surface initial data 7 MB
2015120300/ICMSHgs0cINIT : input file containing initial data for the prognostic variables in spectral representation 35 MB
2015120300/ICMGGgs0cINIUA : input file containing initial data for the prognostic variables in gridpoint representation 101 MB
2015120300/wam_grid_tables : model grid and tables for the wave model 52 MB
2015120300/wam_subgrid_0 : information for model advection, including sub-grid parametrisation for the wave model 12 MB
2015120300/wam_subgrid_1 : information for model advection, including sub-grid parametrisation for the wave model 25 MB
2015120300/wam_subgrid_2 : information for model advection, including sub-grid parametrisation for the wave model 25 MB
2015120300/cdwavein : initial value of drag coefficient for the wave model 63 KB
2015120300/specwavein : initial wave spectra for the wave model 7.6 MB
2015120300/uwavein : initial value of wind speed for the wave model 63 KB
2015120300/sfcwindin : initial value of 10-meter horizontal wind components and sea ice fraction for the wave model 2.2 MB
* NODE.001_01.model.1 and ifs.stat.model.1 files are from an OpenIFS run at ECMWF and they are provided for comparison with the user run.

An example for content of the re-analysis archive files (dates and sizes are different for the different cases and re-analysis sources):

File name   Description Size
README_ei : summary of the content 1037 B
ei_t2_20151201-20151206.grib : 2-meter temperature analysis from ERA-Interim for 20151201-20151206 in every 6 hours 4.1 MB
ei_mslp_20151201-20151206.grib : mean sea level pressure analysis from ERA-Interim for 20151201-20151206 in every 6 hours 4.1 MB
ei_gust_20151201-20151206.grib : 10-meter wind gust forecast from ERA-Interim for 20151201-20151206 in every 3 hours 8.2 MB
ei_p_20151201-20151206.grib : total precipitation forecast from ERA-Interim for 20151201-20151206 in every 3 hours 8.2 MB
ei_t850_20151201-20151206.grib : temperature analysis at 850 hPa from ERA-Interim for 20151201-20151206 in every 6 hours 3 MB
ei_q700_20151201-20151206.grib : relative humidity analysis at 700 hPa from ERA-Interim for 20151201-20151206 in every 6 hours 3 MB
ei_z500_20151201-20151206.grib : geopotential analysis at 500 hPa from ERA-Interim for 20151201-20151206 in every 6 hours 3 MB
ei_u250_20151201-20151206.grib : u and v wind component analysis at 250 hPa from ERA-Interim for 20151201-20151206 in every 6 hours 6.1 MB
ei_u100_20151201-20151206.grib : u and v wind component analysis at 100 hPa from ERA-Interim for 20151201-20151206 in every 6 hours 6.1 MB

## Output figures

The produced figures of the experiments and the re-analysis fields are collected in PNG form. The maps are grouped according to the experiments, the initial dates and the variables. They can be watched by clicking on them one by one in the corresponding folders:

Some figures are gathered in a structured way into a document to have a complete visual impression about the impact of the initial condition, the lead time and the resolution on the forecast quality. These documents are available for storm Desmond at and for storm Xaver at .

Retrieval of the complete package is also possible using wget (wget builds up the same directory structure as in the ftp site):

document.write("% INPUTDIR=" +location.href.replace(/[^/]*$/, '')) % wget -c -r -l4 --no-parent${INPUTDIR}figs/Xaver/     # to download all figures for Xaver
% wget -c -r -l4 --no-parent ${INPUTDIR}figs/Desmond/ # to download all figures for Desmond % wget -c -r -l5 --no-parent${INPUTDIR}figs/           # to download all figures