Operations at CNMCA

COSMO model at CNMCA (ITAF-Met)

Last updated: March 2019

1. Basic model set-up

The Operational Center for Meteorology (CNMCA) of Italian Air Force (ITAF) operates the COSMO model in two different configurations: COSMO-ME and COSMO-IT. Each COSMO configuration is initialized by an ensemble data assimilation scheme based on the Local Ensemble Transform Kalman Filter (LETKF) scheme.

COSMO-ME is integrated over the European area with a 5km grid spacing (Fig.1) using interpolated CNMCA-LETKF deterministic analysis as initial state and IFS forecast fields as lateral boundary conditions.

COSMO-IT is the very high resolution configuration of COSMO model integrated over the Italian domain (Fig.1) and initialized by the high resolution KENDA-LETKF deterministic analysis, using COSMO-ME fields as boundary conditions.

Fig.1: Overview of the operational ITAF NWP system

The atmospheric short-range ensemble prediction system COSMO-ME EPS is running with 40 members over the Euro-Mediterranean domain initialised by the CNMCA-LETKF analysis and driven by EPS boundary fields.

The convection permitting ensemble prediction system COSMO-IT EPS, is running pre-operationally with 20 members over the Italian domain using KENDA-LETKF and COSMO-ME EPS fields respectively as initial and boundary conditions.

Characteristics of configurations
	COSMO-ME	COSMO-IT
Domain Size	1083 x 559	576 x 701
Horizontal Grid Spacing	0.045o (≈5)	0.02o (≈2.2)
Number of Layers	45	65
Time Step (sec)	45	20
Forecast Range (h)	48 (06)/72 (00,12,18 UTC)	30 (06,18 UTC)/48 (00,12 UTC)
Initial Time of Model Runs	00, 06, 12, 18 UTC	00, 06, 12, 18 UTC
Lateral Boundary Conditions	IFS	COSMO-ME
LBC Update Frequency (h)	3	1
Initial State	CNMCA-LETKF	KENDA-LETKF
Initialization	NONE	NONE
External Analyses	SST, SNOW COVER MASK	SST
Cosmo Version	5.06	5.06
Hardware	Hybrid CPU/GPU cluster (CPU Intel, GPU NVIDIA)	Hybrid CPU/GPU cluster (CPU Intel, GPU NVIDIA)
No. of processors used	576 (on 24 nodes)	576 (on 24 nodes)

2. Data Assimilation

The main characteristics of the CNMCA-LETKF data assimilation system, used to initialize COSMO-ME (COSMO-5M of ARPAE) and COSMO-ME EPS, are:

Domain and resolution: the system is running on the Mediterranean-European domain (Fig.2) with 40 ensemble members plus a deterministic member, having a 0.0625° grid spacing (~7 km) and 49 vertical levels. The configuration is defined on a rotated regular grid, the coordinates of rotated north pole are (47.0,-10.0).
Assimilation cycle of 3 hours
Observations: the observational dataset operationally ingested comprises radiosonde ascents (RAOB), surface pressure observations from land and sea stations (SYNOP, SHIP, BUOY), manual and automatic aircraft observations, atmospheric motion vectors from Meteosat, European wind profilers, scatterometer winds from METOP A-B, NOAA/MetopA-B MSUA/MHS and NPP ATMS radiances.
Lateral Boundary conditions: from IFS deterministic run perturbed using ECMWF-EPS.
Surface perturbations: climatological perturbed sea surface temperature.
Model and sampling error: "Relaxation-to-prior spread" multiplicative inflation method according to Whitaker et al. 2012 and additive noise from scaled ECMWF EPS forecasts.

Fig. 2: CNMCA LETKF analysis domain

The main characteristics of the high-resolution KENDA-LETKF data assimilation system, used to initialize COSMO-IT and COSMO-IT EPS, are:

Domain and resolution: the system is running on the Italian domain with 20 ensemble members plus a deterministic member, having a 0.02° grid spacing (~2.2km) and 65 vertical levels.
Assimilation cycle of 3 hours
Observations: the observational dataset operationally ingested comprises radiosonde ascents (RAOB), surface pressure observations from land and sea stations (SYNOP, SHIP, BUOY), manual and automatic aircraft observations, MODE-S data, atmospheric motion vectors from Meteosat, European wind profilers, scatterometer winds from METOP A-B, NOAA/MetopA-B MSUA/MHS and NPP ATMS radiances.
Lateral Boundary conditions: they are from the COSMO-ME EPS members.
Surface perturbations: Stochastic perturbations of soil moisture and SST
Model and sampling error: "perturbation" multiplicative inflation method and climatological additive covariance inflaction.

3. Operational configuration

COSMO-ME and COSMO-IT run four times a day (00UTC, 06UTC, 12UTC and 18UTC). COSMO-ME performs 72 h forecasts for the runs at 00,12 and 18 UTC, while it performs 48 h forecasts for the runs at 06 UTC. COSMO-IT is integrated until 48 h for the runs at 00 and 12 UTC, while it is integrated until 30 h for the runs at 06 and 18 UTC.

Besides the atmospheric forecast models, a wave prediction system (NETTUNO) based on the ECMWF version of the WAM is operationally run (in cooperation with ISMAR-CNR) in two configurations. In NETTUNO-ME WAM is model integrated over the whole Mediterranean (3’) basin driven by COSMO-ME forecast winds. Forecast fields (mean wave period and direction, significant wave height, etc.) are given every 3 hrs up to 72 hrs. In NETTUNO-IT WAM model runs over the Italian domain (1') driven by COSMO-IT wind forecast.

In the atmospheric COSMO-ME EPS, the COSMO model is integrated 40 times with a grid spacing of 7 km, 779x401 grid points/layer and 45 layers. The initial conditions are derived from the CNMCA-LETKF system and the lateral boundaries conditions are from the most recent ECMWF-EPS run. It performs 72 h forecasts for the 00 and 12 UTC runs. The COSMO-ME EPS system provides atmospheric forcing to the NETTUNO-EPS sea state probabilistic model - 3' resolution running up to 48 hour for the 00 UTC run.

In the atmospheric COSMO-IT EPS, the COSMO model is integrated 20 times on the same domain of the COSMO-IT system with a grid spacing of 2.2 km, 576x701 grid points/layer and 65 layers. The initial conditions are from the high resolution KENDA-LETKF system and the lateral boundaries conditions are derived from the COSMO-ME EPS fields. It performs 48 h forecasts for the 00 and 12 UTC runs.