Federal Department of Home Affairs FDHAFederal Office of Meteorology and Climatology MeteoSwiss

Status of the COSMO-1 configuration at MeteoSwiss

Guy de Morsier

COSMO-GM-CORSO, Roma, 6.9.2011

2 COSMO-GM-CORSO, Roma, Sept. 2011 / Status of the COSMO-1 configuration at MeteoSwiss Guy de Morsier

Agenda

• Motivation

• Status of the ARPA-SIM collaboration

• Domain

• Outlook

3 COSMO-GM-CORSO, Roma, Sept. 2011 / Status of the COSMO-1 configuration at MeteoSwiss Guy de Morsier

Motivation for COSMO-1

• Operational target is for 2015• Why increase the grid resolution?

- improve representation of forcing (e.g. topography, land use)

- better capture non-linear interaction between different scales (e.g.

convection)

- improve use of observing systems in the assimilation step

• Focus mainly on Alpine region and Alpine specific problems

4 COSMO-GM-CORSO, Roma, Sept. 2011 / Status of the COSMO-1 configuration at MeteoSwiss Guy de Morsier

Target: COSMO-1 suite in 2015

8x dailyCOSMO-1 +24 hours forecasts

1 km grid size, 100 layers

1040 x 700 grid pointsIFS boundary conditions 10 km grid size, 140 layers

4x daily

5 COSMO-GM-CORSO, Roma, Sept. 2011 / Status of the COSMO-1 configuration at MeteoSwiss Guy de Morsier

Target: COSMO-E suite in 2015

2x dailyCOSMO-E +5 days forecasts

3 km grid size 21 members

VarEPS boundary conditions 20 km

2x daily

6 COSMO-GM-CORSO, Roma, Sept. 2011 / Status of the COSMO-1 configuration at MeteoSwiss Guy de Morsier

Status of the ARPA-SIM collaboration

√ Common domain• Test if a common configuration can be used and

a common evaluation of results operated• Nesting strategy

compare C-1 in C-7 with C-1 in C-2• Decrease damping in upper layers

cf. Wolfgang Langhans1)• Tune the orographic filtering to the stability of the

dynamics• Investigate the sensitivity to the asymptotic turbulent

length scale and the vertical level distribution

1) Convergence of numerical simulations of linear hydrostatic gravity wave, March 11, 2011

9 COSMO-GM-CORSO, Roma, Sept. 2011 / Status of the COSMO-1 configuration at MeteoSwiss Guy de Morsier

Large Alpine Domain698 x 528 gridpoints

CPU of COSMO-2 * 4

y

habs

x

habshgrad *5.0)(

300m filter: max. gr. 18°C-1 with 750m filter: 25°

COSMO-2: 15°

11 COSMO-GM-CORSO, Roma, Sept. 2011 / Status of the COSMO-1 configuration at MeteoSwiss Guy de Morsier

Outlook

• Choice of the orographic filtering should be adapted to the model dynamics!

• Try to run unstable cases without horizontal diffusion

• Set up an assimilation cycle for COSMO-1

• Regular runs from the assimilation cycle

• Evaluate against COSMO-2