Ensemble Configuration

Ensemble Prediction System COSMO-ME-EPS (Operational since 2014)
The atmospheric short-range ensemble prediction system (COSMO-ME EPS) based on the LETKF analysis and the COSMO model is running operationally at COMET (pre-operational since July 2013). The relevant characteristics of the atmospheric COSMO-ME EPS are:
  • Domain and resolution: COSMO model is integrated 20 times on the same domain of the LETKF system.
  • IC and BC: initial conditions are derived from the LETKF system; lateral boundaries conditions are from the most recent ECMWF-EPS run.
  • Model error: stochastics physics perturbation tendencies.
  • Forecast range: 72 hours at 00/12 UTC.

Convection Permitting Ensemble Prediction System COSMO-IT-EPS (Operational since 2018)
The atmospheric short-range ensemble prediction system (COSMO-IT EPS) based on the high-resolution LETKF analysis and the COSMO model is running operationally at COMET. The relevant characteristics of the atmospheric COSMO-IT EPS are:
  • Domain and resolution: COSMO model is integrated 20 times over Italy, with 2.2 km resolution and 65 vertical levels.
  • IC and BC: initial conditions are derived from the high-resolution LETKF system; lateral boundaries conditions are from the most recent ECMWF-EPS run.
  • Model error: stochastics physics perturbation tendencies.
  • Forecast range: 48 hours at 00/12 UTC.
The main features of the operational implementations of the COSMO-ME-EPS and COSMO-IT EPS are summarized in the following table:
System COSMO-ME EPS COSMO-IT EPS
Domain Size (grid points) 779 x 401 576 x 701
Hor. Grid Spacing(degree / km) 0.0625/7 Km 0.02/2.2 Km
Number of members 20 20
Number of layers 45 65
Time step (sec) 60 20
Forecast range (h) 72 hrs 48 hrs
Initial time of Model Runs (UTC) 00,12 UTC 00,12 UTC
Lateral Boundary Conditions most recent ECMWF-EPS most recent ECMWF-EPS
LBC Update Frequency (h) 3 1
Initial state KENDA-LETKF(7 km) KENDA-LETKF(2.2 km)
Model Perturbation SPPT SPPT
Hardware Hybrid CPU/GPU cluster (CPU Intel, GPU NVIDIA) Hybrid CPU/GPU cluster (CPU Intel, GPU NVIDIA)