COSMO-D2 model at DWD

Last updated: 26 May 2020

Contents

1. Going to a higher resolution
2. Basic model set-up
3. Data assimilation
4. Operational Schedule

1. Going to a higher resolution

After the extension of the operational HPC at DWD (from Cray XC30-IvyBridge to XC40-Haswell/Broadwell) the high-resolution COSMO application of DWD (COSMO-DE) was upgraded to a bigger domain, more vertical levels and a higher horizontal resolution.

2. Basic model set-up

The integration domain of COSMO-D2 covers the whole of Germany, Switzerland Austria and parts of the other neighboring countries. It has 651x716 grid points in the horizontal and 65 vertical levels. The lowest level is 10 meters above ground, similar as in COSMO-DE. It also uses the same rotation with pollat=40.0^o and pollon=-170.0^o. The resolution used now is 2.2 km (0.02^o). The rotated lat-lon coordinates of the lower left and the upper right corner of the integration domain are lon = -1.92^o, lat = -2.72^o and lon = 11.08^o, lat = 11.58^o, respectively. Figure 1 shows the integration domain with the domain of the former COSMO-DE indicated.

Fig. 1: Orography (height in m) of the operational domain of the COSMO-D2 at DWD.

COSMO-D2 is running 8 times a day (at 00, 03, 06, 09, 12, 15, 18, 21 UTC) for up to 27 hours. It runs on the Cray XC40 with 2328 cores (97 Haswell Nodes). The MPI decomposition is 43x54 and 6 asynchronous IO tasks.

3. Data assimilation

Since April 2017 the KENDA technique is used as assimilation system for the atmospheric fields for COSMO-DE and it is used now also for COSMO-D2. In addition, the following external analyses are performed for the COSMO-D2.

• A sea surface temperature (SST) analysis (00 UTC),
• a snow depth analysis (00, 06, 12 and 18 UTC)

The latent heat nudging for assimilating radar data is performed for all runs of the COSMO-Model at 00, 03, 06, 09, 12, 15, 18, 21 UTC.

4. Operational schedule

DWD runs COSMO-Model 5.07 (since 21.04.20) and INT2LM 2.07 (since 11.12.19) in operations.