Hirlam Physics Developments

Hirlam Physics Developments

Sander TijmHirlam Project leader for physics

Overview Results of this year Verification Shallow convection Turbulence and convection for mesoscale Tuning of synoptic scale model

Hirlam physics developments

Mesoscale

Verification Surface Turbulence &

shallow convection Deep convection? Radiation

Synoptic scale EPS & boundaries Verification Surface (tuning) Turbulence Shallow convection Deep convection Radiation Wave drag

Results this year Hirlam physics in IFS (Convection, turbulence and

radiation, Sass, Rontu and Niemela) Moist CBR (Sass & Tijm) MSO/SSO (Rontu) Surface scheme (snow and forest, talk of Stefan after

this one) Sloping surfaces radiation (Senkova) Stable PBL (GABLS, De Bruijn, Perov & friends)

Snow on ice (Vihma) Lake model (Kourzeneva & Tisler) Urban characteristics (Baklanov & Mahura)

Moist CBR Impact on cloud water profiles

Moist CBR Impact on precipitation

Snow scheme

Verification Verification working group to check physics of

mesoscale model Cooperation with Aladin Focus on relatively normal weather, which is challenge

for physics List of cases and progress of work can be found on:

http://www.knmi.nl/~tijm/Verif/Verifworkg.html

Verification of models against observations Model intercomparison Baseline for future model improvement

Verification

Cloud top temperatures (Zingerle)

KF-RKREFObs

Entrainment/Detrainment

Overprediction of high clouds Too much deep convection, too little

convection of intermediate depth Too little entrainment (lowering of

updraft temperature) and/or detrainment (stopping updraft mass flux)

Can also be seen in shallow cumulus

Specific humidity profiles for ARM with LES (left) and Hirlam 1D using =z-1 and =0.00275

Shallow convection (De Rooy)

Mass flux profiles for LES (left) and =z-1 + =0.00275 (right)

Shallow convection

Massflux profiles for LES (left) and =z-1 + new (right) where depends on cloud depth and critical fraction

Shallow convection

qt profiles for ARM with LES (left) and Hirlam SCM (right) with =1/z and new formulation c

Shallow convection

EDMF scheme (Siebesma)

•Nonlocal (Skewed) transport through strong updrafts in clear and cloudy boundary layer by advective Mass Flux (MF) approach•Remaining (Gaussian) transport done by an Eddy Diffusivity (ED) approach

zinv

EDMF

h (km)

x(km)

0

5

1

Use LES to derive updraft model in clear boundary layer.

0

Updraft at height z composed

of those grid points

that contain the highest p%

of the vertical velocities:

p=1%,3%,5%:

EDMF scheme One scheme for boundary layer and cumulus convection Will be developed within AROME framework, as an

option Cooperation with ECMWF

After successful implementation in mesoscale model, incorporate in synoptic scale model to limit boundary effects

Surface developments New surface scheme (Gollvik) for synoptic scale

Extension of surface scheme with lake model (Kourzeneva)

Extension with improved description of snow on ice (Vihma)

Urban impact to be included (Mahura and Baklanov) Tuning of surface characteristics (Garcia)

Modeled temperature, sensitivity to lake depth(Flake model, Kourzeneva)

Tuning of syn. Hirlam Sytematic errors in synoptic scale Hirlam:

too much fog too many and intense small scale lows too strong convection dynamics feedback (noisy pressure

pattern) Overestimation of evaporation over sea may be an

important factor in the development of these phenomena, together with:

Vertical diffusion in stable and neutral conditions Deep convection parameterization

Tuning of syn. Hirlam

Small scale developments

Summary Many developments for turbulence, shallow and deep

convection, surface modelling. Shift of main effort towards the mesoscale physics Synoptic scale remains important, for mesoscale

boundaries and SREF Synoptic physics as close as possible to mesoscale

physics, to reduce boundary effects