COSMO model activities in theatmospheric dynamics group at ETH

Heini WernliClaudia FrickStephan PfahlAndreas Winschall

Astrid KerkwegMaxi BöttcherMatthias ZimmerGregor GläserChristiane Hofmann

What for do we use the COSMO model?

Studies on the dynamics of weather systems

Studies on the atmospheric water cycle

Studies on atmospheric chemistry and transport

How do we use the COSMO model?

Studies on the dynamics of weather systems

high-resolution model simulations

sensitivity experiments (on/off of physical processes)

test / improvement of physical parameterizations

Studies on the atmospheric water cycle

COSMOtag: implementation of water tagging

COSMOiso: implementation of stable water isotopes

Studies on atmospheric chemistry and transport

development of ECHAM5-COSMO-MESSy

(comprehensive, online-coupled global-regional chemistry model system)

EUMETSAT: RGB-composite

Saharan dust storm March 2004

0°E

airborne dust

clouds

40°N

20°NSahara Desert

1000 km

Gläser & Knippertz

NS

Z

Y

coldpoolρc > ρsρs

threshold for |v10m| ≈ 10-12 m/s

how to exceed the threshold ??

Concept of the dust mobilisation

resulting flow

vres= vb + |vc| vres= vb - |vc|

vb

vcvc

vbvb

vb: background flow

vc: outflow out of the coldpool

Gläser & Knippertz

coldpool

heating due to condensation, freezing, resublimation

cooling due to evaporation, melting, sublimation

Dipole of latent heating/cooling

N-S-cross-section at 4°E COSMO 2.8 km

northern latitude, deg

pres

sure

, hP

a

K/h

Gläser & Knippertz

Gust front moving into the Sahara

longitude, deg

latit

ude,

deg

max: > 14 m/s

min: < 2 m/s

"undisturbed" flow: Ø 8-10 m/s

→ Δ = ± 6-8 m/s !

COSMO 2.8 km 10m wind field

(m/s)

Gläser & Knippertz

19-21 December 2005

low-level PV and SLPfrom ECMWF analyses

Pressure deepening of34hPa/24h !

Rapid North Atlantic cyclogenesis

Maxi Böttcher

Rapid North Atlantic cyclogenesis

COSMO model hindcast simulations

Horizontal resolution of 14km, 40 vertical layers

Initial and boundary data (every 6h) from ECMWF analyses

4 model simulations for early phase of development:

- control- dry run- no LHR in box- SST-3K in box

ECMWF analysis

Maxi Böttcher

control dry

no LHR in box

Rapid North Atlantic cyclogenesisCOSMO model sensitivity experiments (+42h)

SST-3K in box

Maxi Böttcher

Parameterization of snow melting

Intense snow storms occur during situation with Ts ≈ 0°C, typically with presence of melting layer above the surface

current melting scheme: if T > 0°C then snow rain

Claudia Frick

Parameterization of snow melting

Intense snow storms occur during situation with Ts ≈ 0°C, typically with presence of melting layer above the surface

current melting scheme: if T > 0°C then snow rain

Now with 1D-COSMO in cooperation with Axel Seifert:development of new scheme with liquid water fraction

T(z,t) from radiosonde snow mixing ratio(z,t) snowmelt mix. ratio(z,t)

Claudia Frick

+ 00-UTC runso 09-UTC runs

Verification of COSMO model QPFs with SAL

Summer 2007, German part of COPS regionForced frontal convection High-pressure convection

COSMO-EUCOSMO-DE

Matthias Zimmer

18R0

18R1 < 18R018R2 < 18R1

In principle, stable isotopes allow to reconstruct water transport paths and atmospheric conditions during phase transitions (e.g. temperature) simultaneously.

Stable water isotopes in the COSMO model

Stephan Pfahl

Water transport and phase transitions in the model

Inclusion of parallel water cycle in the model affects:

• advection (Bott scheme)• turbulent transport

• implicit numerical scheme (not positive def.)• influence of subgrid scale clouds (?)

• convection parameterization• cloud microphysics, saturation adjustment

• still missing: land surface scheme

Output: δ18Ovap(x,t), δ18Oprec(x,t), δ2Hvap(x,t), δ2Hprec(x,t)

Stephan Pfahl

deuterium excess in near-surface water vapour

left: COSMO simulation; right: alternative Lagrangian diagnostic

First application of COSMOiso (18 Nov 2001)

Stephan Pfahl

MACCHIATO Modeling AtmosperiC CHemIstry And Transport fom the global tO the local scales

Modeling of atmospheric chemistry on all scales

consistent treatment of chemistry on all scales use ECHAM5/MESSy (boundary data) develop COSMO/MESSy

MESSy: Modular Earth Submodel System

contains submodels for chemistry calculation and diagnostic; each process (chemistry, deposition, sedimentation etc.) is a seperate (switchable) submodel

Aims: zooming option for e.g., campaign modelling, down-scaling of climate projections, chemical weather forecasts etc.

Astrid Kerkweg & Patrick Jöckel (DLR)

An arbitrary number ofCOSMO models run in parallel in the same MPI environment and provide therequired boundary data via MPI exchange on-line. => avoid dumping, storage and input of huge data amounts (e.g., some 100 chemical species)

COSMO 1

COSMO 2 COSMO 3 COSMO X . . .

COSMO 31 COSMO 32

COSMO 321

ECHAM5

COSMO 12

The vision of “ONLINE-COUPLING”

Summary

COSMO is the meteorological model in our groupStrong interest in exchange & cooperation with MeteoSwiss and C2SM

Model applications

- detailed analysis of real case study (sensitivity) experiments

for various weather events

- idealized channel-model baroclinic wave experiments

Model development

- new melting scheme with liquid water fraction

- implementation of tagging and stable water isotope physics

- coupling with ECHAM5-MESSy for high-resolution chemistry

simulations with consistent boundary conditions