COSMO-DE model at DWD

Last updated: September 2017


Contents

  1. Development of a COSMO-Model Version for very high-resolution
  2. Basic model set-up
  3. Data assimilation
  4. Operational Schedule

1. Development of a COSMO-Model Version for very high-resolution

In 2003, DWD started the Aktionsprogramm 2003, a temporary programme to improve the weather forecasting in Germany. One of the subprojects was the development of a model-based nowcasting system. For that, the COSMO-Model was used, but several extensions have been implemented, to suit the needs of such a system. The main new developments for the COSMO-Model are:

Since April 2007, the new version of the COSMO-Model is running operational in the COSMO-DE application of DWD. This application is described in more detail here.

2. Basic model set-up

The integration domain of COSMO-DE covers the whole of Germany, most part of the alps and some smaller parts of the neighboring states. It has 421x461 grid points in the horizontal and 50 vertical levels. The lowest level is 10 meters above ground, similar as in COSMO-EU. COSMO-DE uses the same rotation as COSMO-EU, with pollat=40.0o and pollon=-170.0o. The resolution used right now is 2.8 km (0.025o). The rotated lat-lon coordinates of the lower left and the upper right corner of the integration domain are lon = -5.0o, lat = -5.0o and lon = 5.5o, lat = 6.0o, respectively. Figure 1 shows the integration domain with 421x461 grid points.

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

COSMO-DE is running 8 times a day (at 00, 03, 06, 09, 12, 15, 18, 21 UTC) for up to 24 hours. It runs on the same computer as COSMO-EU on 256 processors.

3. Data assimilation

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

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

4. Operational schedule

Table 1: The operational suites for COSMO-DE at DWD in September 2017.
Suites Pre-processing Interpolation COSMO-DE Post-processing
Analysis Snow Depth
Sea Surface Temp
same as FCST namelist
YUSPECIF
 
Forecast (FCST) - namelist
OUTPUT
namelist
YUSPECIF