Regional Reanalysis

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EURO4M – WP2: Regional Reanalysis
Overview
Dale Barker, Tomas Landelius, Eric Bazile, Christoph Frei, Phil Jones
2 April 2012
© Crown Copyright 2012
2012.Source:
Source:Met
MetOffice
Office
EURO4M WP2
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WP2.1 Building capacity for advanced regional data assimilation (MetO)
WP2.2 Dynamical downscaling of ERA (SMHI).
WP2.3 2D mesoscale downscaling (Météo France).
WP2.4 Evaluation (MeteoSwiss).
WP2.5 Improvement of input data for reanalyses (UEA)
Now
© Crown Copyright 2012. Source: Met Office
WP2.1 Building capacity for
advanced regional data assimilation
Current
12km grid
480 x 384
• Horizontal domain unchanged from last year.
• Decision made in FY2011-12 to align EURO4M vertical levels, physics, etc with
global NWP/climate model (previously aligned with regional NWP ensemble).
© Crown Copyright 2012. Source: Met Office
ECMWF
“interface”
Met Office
UM
Running at
ECMWF
© Crown Copyright 2012. Source: Met Office
Regional NWP – Why Bother?
Benefit Of European Regional NWP vs 25km global model (UM):
Regional NWP
+ Regional DA
Surface Wind-Speed
T+6 – T+48
T+0 – T+6
Cloud Amount
T+0 – T+48
T+0 – T+6
Visibility
T+0 – T+48
T+0 – T+12
Surface Temperature
T+0 – T+48 (UK only)
T+0 – T+12/24 (NAE/UK)
Upper-Air Temperature
Upper-Air Wind Speed
PMSL
6hrly Acc. Precipitation
Focus for EURO4M: ‘Regional Reanalysis – Why Bother?’
© Crown Copyright 2012. Source: Met Office
Global/Regional Reanalysis Configurations
ERA-Interim
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T255* (80km), 60 levels
T159 (125km) 4D-Var
12-hour analysis window
Assimilate:
• conventional obs
• satellite radiances
* Note ERA-Clim up to T511 (~40km)
EURO4M
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12km, 70 levels
12-36km 4D-Var
6-hour analysis window
assimilate:
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conventional obs incl visibility
satellite radiances
Ground-based GPS
Cloud
Precipitation
• Initial state and boundary
conditions from ERA-Interim/
Clim analyses
© Crown Copyright 2012. Source: Met Office
First attempt at reanalysis...
• Floods in Poland,
May 2010
eastern Europe
• Severe storms
June 2010
France/Spain
• Russian heatwave
July 2010
spreading West,
forest fires
© Crown Copyright 2012. Source: Met Office
ERA-Interim
Russian heatwave,
July 2010
e-obs
12km EURO4M
Tmax
10-07-10
© Crown Copyright 2012. Source: Met Office
Verification vs Radiosonde
European Temperature rms error: May-July 2010
T+0
T+6
ERA-Interim
EURO4M 12km
© Crown Copyright 2012. Source: Met Office
GA3: See Renshaw talk
Developments for 2012/13
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Variational bias correction
ODB – obs monitoring. ECMWF collaboration.
Extend observations dataset
Cloud and Precipitation assimilation
Validation – extreme statistics
Collaborate on cross-validation
• ‘Pre-Production’ Reanalysis: 2010 – 2011 period
• Impact of 4D-Var assimilation resolution (12-36km)
© Crown Copyright 2012. Source: Met Office
Dynamical downscaling and reanalysis over
Europe (WP2.2 – 2.3)
3D-Var Re-analysis at 22 km,
60Levels over Europe (SMHI)
Downscaling
Dx ~ 5 km over Europe
Courtesy of T. Landelius (SMHI)
More observations
2D analysis at Dx ~5 km
By adding details with topography and more observations,
the quality of the analysis should improve … ~ 4000 obs
(1200 over France)
© Crown Copyright 2012. Source: Met Office
WP2.3 2D reanalysis (SMHI)
HIRLAM 22 km
© Crown Copyright 2012. Source: Met Office
Downscaled to 5 km
MESAN t2m analysis
(observations as black dots)
WP2.3 observations for
2D reanalysis (SMHI)
In total some 10,000 unique stations.
This is still far from all observations available in the national archives!
GA3: See Unden, Landelius talks
© Crown Copyright 2012. Source: Met Office
WP2.3 Ongoing work
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Validation of the analyses
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Against observations (particularly for T2m, Rh2m, 24-h cumulated precipitation)
Assessment of the snow depth and the river flow by using a surface scheme and a
hydrological module forced with reanalyses surface variables.
Improvement of the downscaling method:
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Problem of the vertical interpolation over the mountainous areas especially for the
temperature ;
usage of a lake climatology to improve the lake surface temperature.
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Development of precipitation analysis, the usage of Tmin and Tmax for reanalysis
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Technical issues:
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To create a reanalysis domain (~5km scale) over Europe that best fit SMHI domain (at
22 km scale), i.e. changing the geometry from rotated lat-lon to Lambert conformal);
Converting GRIB files from SMHI to specific format type
Usage of additional observations not available in GTS.
Specific treatment for the wind with a dynamical adaptation or by DFI ?
GA3: See Soci talk
© Crown Copyright 2012. Source: Met Office
WP2.5 Improved Input Data
(UEA)
Overall Process
GA3: See Jones talk
© Crown Copyright 2012. Source: Met Office
WP2.4 Evaluation
(MeteoSwiss)
• Formally begins April 2012.
• MeteoSwiss: precipitation variations in Alpine regions.
• Met Office: Reanalysis sensitivity to resolution, technique. Observation
impact.
• SMHI: compare MetO/HIRLAM reanalyses.
• MeteoFrance: Evaluate MESAN/SAFRAN.
• DWD: verify WV, cloud, precip, radiation with CM-SAF Investigate
satellite radiance calibration.
Using existing datasets, reanalyses, and datasets developed in WP1
© Crown Copyright 2012. Source: Met Office
WP2.4 Evaluation
(MeteoSwiss)
20 km grid
5 km grid
Precipitation at meso-scale in complex topography (Alpine region)
Consistency between obs. datasets (spatial pattern, annual cycle) for precip extremes?
High-resolution regional reanalyses vs. global reanalysis?
Representation of interannual to decadal variations by regional reanalyses?
© Crown Copyright 2012. Source: Met Office
GA3: See Frei discussion
EURO4M WP2
Deliverables/Milestones
Year 1
Year 2
Now
Year 3
Year 4
• Deliverables on track.
• Year 1-2, largely preparation (much technical work).
• Year 3-4 ‘pre-production’ runs plus evaluation (enhanced collaboration).
© Crown Copyright 2012. Source: Met Office
Questions/Discussion?
© Crown Copyright 2012. Source: Met Office
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