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WGNE 27 High Resolution Modeling

Compiled by Bill Lapenta & Gary Dietachmayer

Thanks to WGNE Members for the contributions

Model Configuration

•  Main deterministic UK models: • Global 25km (DA) –

•  North Atlantic and Europe 12km (DA) to 48 hours

•  UK 4km and 1.5km (DA) to 36 hours

•  New 4km downscaler model - Runs reconfiguring from Global analysis and driven directly by (3 hourly) global LBCs to 5 days

•  To provide weather detail at longer range (e.g. shower advection)

•  Improved performance over UK4 for some metrics – benefits of simpler nesting / up-to-date LBCs outweigh loss of benefits of DA

Temperature/Wind (mean rms errors: 17th March-10th Sept)

Surface Temperature and Wind

Temperature (VT 3,9,15,21z) Wind (VT 3,9,15,21z)

Temperature (VT 0,6,12,18z) Wind (VT 0,6,12,18z)

UK4

UK4X

Experimental 1.5km system •  Aim for system capable of using

radar data •  3dVAR (3 hourly initially) •  Latent Heat nudging •  Doppler winds

•  Best coverage is over Eastern NSW (Sydney Domain)

• Main foci so far •  Radar & QPE quality control •  Doppler (clear air) wind QC •  Assessing model performance •  Configuring 3dVAR and Latent Heat

Nudging (ongoing)

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•  Address model issues •  Still have issues with excessive vertical

velocities •  Resolution does matter! Model & DA

•  Still hopeful for operational 1.5km assimilation of tropical convection

•  Brisbane & Darwin provide useful data sets

•  Includes ARM site

•  Explore other cases •  Severe storms in Melbourne and Sydney

•  Model better behaved

• Objective verification •  Rainval, Rainval-hourly, blob-based

motion verification

Area & Volume vs Rainfall Rate

•  1.5km – too much convection & too strong •  4,5 & 6 hour forecasts •  Model calibration •  3dVAR small effect •  Latent Heat Nudging needs calibration

•  0.05o (5km) & 0.11o (12km) problems with heavy precipitation too

•  3,4,5,….,14 hour forecasts •  Little sensitivity to forecast length •  APS0 5km delivers lot of rain at low rate,

and has odd peak at 100 mm/hour

Obs 3dVAR+LHN 3dVAR only

Obs 3dVAR+LHN 0.05o (FC only) 0.11o 4dVAR

mm/hour

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Observed (Radar + Gauge) 1.5km 3dVAR 1.5km 3dVAR + LHN

Problem with latent heat nudging when “adding” convection

Latent heat nudging worked better when “removing” convection

Examples of 3dVAR and Latent Heat Nudging at 1.5km

Hourly Accumulated Precipitation Ending 08 UTC 10 Jan 2011

Overview high resolution modeling activities in CMA�

•  Motivation –  To implement a 3-km resolution operational NWP system

covered the whole China in the next 2 or 3 years

•  Upgrade activities of GRAPES_Meso –  Improve the model dynamic core: high-accuracy advection scheme; 4th order

horizontal diffusion with orographic flux limiting –  Two-moment microphysics scheme development –  GPS/PW assimilation –  Radar radial wind & reflectivity assimilation –  AWS assimilation –  Cloud analysis

•  Current status –  Test system in Guangzhou Meteorological Bureau�

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Main features of high resolution GRAPES_Meso�

•  Model   Non-hydrostatic   Arakawa C-grid & terrain-following

Z   2-time-level SISL, but piecewise

Rational Method for scalar advection   Raymond filter to remove the

unresolved topo. & mitigate the steepness

  4th-order horizontal diffusion with orographic flux limiting

  Physics package   RRTM LW & Dudhia SW   Two-moment microphysics   NOAH land surface   YSU nonlocal PBL

•  3D-VAR   Model grid space incremental

analysis   GTS, local radio sonde,

Doppler radar VAD, AWS, GPS/PW, FY-2C/2D cloud drift wind, Doppler radar radial wind & reflectivity

  Cloud analysis based on radar reflectivity

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Model Domain �

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 NCEP 1.33 km Resolution within 4km CONUS NAM nest

 Application to Hurricane Irene over the Bahamas

  12 UTC 24 Aug to 00 UTC 26 Aug   MSLP (mb)   10m wind   1h precip (in)

 NCEP 1.33 km Resolution within 4km CONUS NAM nest

 Application to Hurricane Irene over the Bahamas

  12 UTC 24 Aug to 00 UTC 26 Aug   10m wind   Simulated reflectivity

GME Δx = 30/20 km

COSMO-RU7 Δx = 7 km

COSMO-RU2 Δx =2.2 km Domain: 900 km * 1000 km Grid: 420*470 * 50 Step: 2.2 км Time step: 15 сек Forecast: 24 час. Cores: 400

Grid: 368 642 * 60 Step: 30 / 20 км Time step: 110 сек Forecast: 7 суток

Гидрометеорологический центр Российской Федерации

COSMO-RUsib Δx =14 km

DWD (Germany) global model GME: initial and boundary data

Domain: 4900 km * 4340 km Grid: 700*620 * 40 Step: 7 км Time step: 40 сек Forecast: 78 час. Cores: 800

Domain: 5000 km * 3500 km Grid: 360*250 * 40 Step: 14 км Time step: 80 сек Forecast: 78 час. Cores: 48.

12 11/7/11 Rivin Gdaly, HMC of Russia

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"   Initial and boundary data: 00,06,12 and 18 UTC, GME (DWD)

"  Forecast: 24 h "  Grid step 2.2 km "   Grid:

420 * 470 * 50 (Moscow) 420 * 470 * 50 (Sochi)

"   SGI  Al'x  4700  (1664 cores) (832 processors Itanium 2, 3,3 Tb memory)

"   Run time for 24 h. 27 min: 400 cores

Гидрометеорологический центр Российской Федерации

COSMO-RU02: domain, time of run with MPI

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COSMO-­‐RU2,  12-­‐23  February  2011,  T2m  (prepared  by  A.  Bundel  &  Versus2,  

 Krasnaya  Polyana    &  Sochi  ,)  

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ECMWF 2011 Slide 15

Plans for next two years

 Experimentation with a fast Legendre transform

 Experimentation towards a future operational implementation of T2047 (~10km)

 Global case studies at T3999 (~5km) and T7999 (~2.5km) resolution.

  Increased vertical resolution to 137 levels

 Further testing of the (moist) non-hydrostatic IFS model formulation and evaluation of various efficiency gains.

  Improving the conservation of tracers and cloud species.

 Further extend the applicability of the IFS model towards cloud resolving scales.

Simulation of deep convective systems on the small planet

IFS NH dynamics coupled with the prognostic microphysics of the current cycle is used to simulate deep convective systems on a small planet at resolutions where explicit convection is permitted by the dynamics (Δx<3 km).   Idealized test cases (Weisman and Klemp, 1982, 1984) are qualitatively well reproduced by the IFS

 Without parametrized convection the IFS results are quite sensitive to the numerics and to the tuning of the microphysics.  The results suggest limits to the applicability of the existing convection scheme for resolutions 5 km< Δx <9 km.

BACKUP SLIDES

© Crown copyright Met Office

Plan to routinely run a 2.2 km ensemble from 2012 (MOGREPS-UK), embedded within MOGREPS-R (EU) (18 km -> 12 km) ensemble.

Convective-scale Ensemble

Nigel Roberts

36-hour forecasts 12 members 6-hour cycling Downscaling – No high-resolution initial perturbations or forecast perturbations to start with Case study experiments 24 members 1.5 & 2.2 km

© Crown copyright Met Office

Morpeth flood event 5-6 Sept 2008 Probability of exceeding 50mm in 17 hours

UKV 24 members 2.2km 24 members

Neighbourhood 13.5 x 13.5 km (3x4.5km pixels)

© Crown copyright Met Office

Comparison of ensemble sizes and resolution

Agreement (using Fractions skill score) between smaller and degraded resolution ensembles and full 24 member 1.5km ensemble

On-going development of Arome ensemble prediction system

Downscaling of global Ensemble Prediction System

Mesoscale Ensemble prediction system, first trials

Probability of reaching 50mm threshold for 24-hour precip.

Obs reaching 50mm = red squares 21

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COSMO-DE- Ensemble Prediction system

Susanne Theis, Christoph Gebhardt, Zied Ben Bouallègue, Michael Buchhold

since 9 Dec. 2010 the pre-operational phase has started (20 members)

motivation: simulations with a convection-permitting model (COSMO-DE with 2.8 km horizontal grid size) have a strong non-deterministic behaviour use an EPS to asess the model uncertainties

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Probability Maps

+ 13h + 10h

+ 7h probability of snow > 5cm

produced by ensemble

Current status of Arome at Météo-France

Operational since december 2008

grid : 2.5km

60 levels up to 1hPa

3D-Var every 3 hours

Coupled to global model Arpege

Assimilation of conventional, satellite and radar (radial winds and reflectivities)

Reflectivity observations

In 2014,

resolution will increase from 2.5 km to 1.3km,

From 60 to around 90 levels

Over the Alps, example of resolution change

More levels in lower

troposphere