© Crown copyright Met Office UM 4D-Var Regional Reanalysis Progress Richard Renshaw, Stephen Oxley,...
-
Upload
jessica-saunders -
Category
Documents
-
view
217 -
download
0
Transcript of © Crown copyright Met Office UM 4D-Var Regional Reanalysis Progress Richard Renshaw, Stephen Oxley,...
© Crown copyright Met Office
UM 4D-Var Regional Reanalysis ProgressRichard Renshaw, Stephen Oxley, Adam Maycock, Peter Jermey,
Dale Barker, DingMin Li
© Crown copyright Met Office
Contents
Progress with technical work
First attempt at reanalysis
Developments for 2012/13
© Crown copyright Met Office
Set up and demonstrate an advanced regional reanalysis system
Based on operational North Atlantic/Europe LAM
Planning to analyse 2010 & 2011
WP2.1 Building capacity for advanced regional data assimilation
© Crown copyright Met Office
12km grid
480 x 384
MetO Regional Reanalysis: Horizontal Domain
© Crown copyright Met Office
Technical work
Build a reanalysis system
• to run at ECMWF
• taking observations,
start file,
boundary conditions
from ECMWF archives
• storing analyses in ECMWF archives
• and producing data to validate the reanalysis.
© Crown copyright Met Office
Running atECMWF
ECMWF
“interface”
Met Office
© Crown copyright Met Office
Technical Highlights
• Set up Met Office systems on ECMWF IBM• Use observations from mars (ECMWF BUFR format)• Preprocess satellite radiances
• reconstruct level 1b files from BUFR data• convert level 1b counts to level 1c radiances (AAPP)• map between instrument grids (e.g. AMSU+MHS to IASI)
• Convert and map ERA-Interim GRIB files to UM file format, for start files and boundary conditions
• Use ‘CYLC’ to develop and run a reanalysis suite
© Crown copyright Met Office
CYLC: Scheduling System
CYLC, written by Hilary Oliver (NIWA)
http://hjoliver.github.com/cylc/
+ROSE – adds interfaces and configuration management
© Crown copyright Met Office
Why CYLC ?
• Will replace ageing Met Office system• Can build, run, monitor suites of any complexity• Portable – Open source• Flexible• Intelligent job scheduling
- define dependencies for each task
- tasks will run early if possible
© Crown copyright Met Office
sample CYLC suite
© Crown copyright Met Office
Dale’s challenge
Regional reanalysis
- why bother ??!
© Crown copyright Met Office
Evidence from operational NWP
25km Global
vs
12km NAE
© Crown copyright Met Office
...the benefits of resolution
forecast range
screen temperature rms error (K)
global 25km
NAE 12km
© Crown copyright Met Office
...and the disadvantage of boundaries!
forecast range
mean sea level pressure rms error (Pa)
global
NAE
© Crown copyright Met Office
ERA-Interim vs 12km EURO4M
• 12km, 70 levels• 36km 4D-Var• 6-hour analysis window• assimilate:
• conventional obs incl vis• satellite radiances• Ground-based GPS• Cloud• Precipitation
• Initial state and boundary conditions from ERA-Interim analyses
• T255 (80km), 60 levels• T159 (125km) 4D-Var• 12-hour analysis window• assimilate:
• conventional obs• satellite radiances
© Crown copyright Met Office
model orography
ERA-Interim
Model T255 (80km)
Var T159 (125km)
Met Office
Model 12km
Var 36km
© Crown copyright Met Office
First attempt at reanalysis...
May 2010
June 2010
July 2010
• Floods in Poland, eastern Europe
• Severe storms France/Spain
• Russian heatwave spreading West, forest fires
© Crown copyright Met Office
Poland floods, 16th May 2010
http://eca.knmi.nl/
e-obsgridded
24hr rainfall
© Crown copyright Met Office
Poland floods, 16th May 2010
Czech Hydrometeorological Institute
radar24hr rainfall
© Crown copyright Met Office
12km reanalysise-obs
Poland floods, 16th May 2010
© Crown copyright Met Office
ERA-Interime-obs
Poland floods, 16th May 2010
© Crown copyright Met Office
Russian heatwave, July 2010
Tmax, 10-07-2010
e-obs
© Crown copyright Met Office
Tmax10-07-10
ERA-Interim
12km EURO4M
obs
© Crown copyright Met Office
Verification vs Radiosonde
T+0 T+6
Temperature rms error
ERA-Interim
EURO4M 12km
© Crown copyright Met Office
Verification vs Radiosonde
T+0 T+6
Vector wind rms error
ERA-Interim
EURO4M 12km
© Crown copyright Met Office
Developments for 2012/13
• Variational bias correction
• ODB – obs monitoring
• Extend observations dataset
• Cloud and Precipitation assimilation
• Validation – extreme statistics
• Collaborate on cross-validation
© Crown copyright Met Office
n
ib
airi
scan xfccbias1
)(
Variational Bias Correction
Airmass-dependent bias correction of satellite radiances (based on Harris and Kelly, 2001)
Currently coeffs c are calculated off-line monthly
VarBC will give smooth and automatic updating
Work is underway – finish in 2012
(DingMin Li, Dale Barker, Andrew Lorenc)
© Crown copyright Met Office
ODB – obs monitoring database
• Established ECMWF database + utilities• Array of tools available “for free”
• Metview macros (quick look)• Obstat (detailed stats / graphics)
• Replaces several diverse monitoring tools at MO• Joint development
• Currently ~1.5 years into 3 year joint funded post at ECMWF (Peter Kuchta)
• Setting up Obstat at MO
• Other NMSs already using ODB (CAWCR, KMA)
© Crown copyright Met Office
Extend observations dataset
• Work with UEA (WP2.5) to extend surface
and sonde datasets
• Seeking sub-daily raingauge data...
© Crown copyright Met Office
Cloud + Precip assimilation
• Operational UK models assimilate cloud products (satellite) and rainfall (radar, latent heat nudging)
• For EURO4M, plan to assimilate cloud reports and raingauge accumulations from surface stations
• Needs development work (2012/13):• source sub-daily raingauge accumulations• decode and interpret surface reports (Peter Francis)• quality control• assimilate rainfall accumulations in 4D-Var• reduce effect that analysis increments trigger rain in
model
© Crown copyright Met Office
Validation - Extremes
• High impact weather• Should show a benefit for regional reanalysis• Focus on:
• precipitation• temperature• winds
• Need to look at probability distributions (pdf’s), e.g.• number of values outside 10th/90th percentile• count consecutive days with high/low values• accumulated precipitation over several days
© Crown copyright Met Office
Collaboration – Cross-Validation
Compare our reanalysis against:• SMHI• ERA• Obs climatologies• Others ?
© Crown copyright Met Office
Summary
• Reanalysis system ready to run
• Already better than ERA-Interim in some features, but not all (yet!)
• Science development and testing this year
© Crown copyright Met Office
Questions ?
With thanks to:
Tom Green, Nigel Atkinson, Sreerekha Tr, others...
© Crown copyright Met Office
Extra slides...
© Crown copyright Met Office
First attempt at reanalysis...
May 2010
June 2010
July 2010
• 3 x 1 month runs, with overlap
© Crown copyright Met Office
How long to spin up ?
rms surface pressure
© Crown copyright Met Office
How long to spin up ?
rms screen temperature
© Crown copyright Met Office
100km 4D-Var12km 4D-Var
Impact of Var resolution
© Crown copyright Met Office
Verification vs Radiosonde
T+0 T+6
Relative Humidity rms error
ERA-Interim
EURO4M 12km
© Crown copyright Met Office
Global ODB trial output
NH Surface T mean (o-b)