recent developments at dwd
DESCRIPTION
Recent developments at DWD [email protected] Deutscher Wetterdienst , D-63067 Offenbach, Germany based on experiments / plots by Klaus Stephan. Direct Nudging of Radar Radial Velocity Data Status of OPERA Latent Heat Nudging for COSMO-EU. nudging of radar radial velocity: methodology. - PowerPoint PPT PresentationTRANSCRIPT
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 1
Recent developments at DWD
[email protected] Deutscher Wetterdienst, D-63067 Offenbach, Germany
based on experiments / plots by Klaus Stephan
• Direct Nudging of Radar Radial Velocity Data
• Status of OPERA
• Latent Heat Nudging for COSMO-EU
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 2
nudging of radar radial velocity:methodology
pre-processing , done twice (first use time, obs time) for each radar scan
1. at each observation point:
• correct observed radial wind for sedimentation speed of the hydrometeors
• calculate observation increment of radial wind component (at obs point)
(requires: - bi-linear interpolation of model horizontal wind to obs point- project model horizontal wind to radial direction )
• re-folding aliased measurements (according to quality flags of the obs)
• exclude all increments > ± 5 m/s
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 3
nudging of radar radial velocity:methodology
2. at certain model grid points (i,j) (e.g. every 20 km lat / lon) :create vertical profiles of pseudo obs (of radial velocity, as a kind of superobbing)
• assign all obs increments (at obs points)within ±1° (azimuth) and ±10 km (range)horizontally to this model grid point
• pseudo obs (of radial velocity)= radial comp. of model wind+ obs increment (at model level)
(i,j)range
20 km 2°(i,j)
model g. pts.
• get obs increments at model levelsas weighted average of increments at obs points(weights depends on height differences)
verticalcross
section
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 4
nudging of radar radial velocity:methodology
umod
vmod
upseudo
vpseudo
Radar
modelgrid pt.
pseudo observation in radial wind
current model horizontal wind
current model radial wind
current increment in radial wind
current target wind
azimuth processing in nudging at each time step : horizontalplain • project current model wind to radial direction
• current observation increment= pseudo observation of radial velocity - model radial velocity
• increment : - physically: radial velocity
- formally: wind vector, always
in radial direction ! treat like radiosonde wind increment in nudging scheme
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 5
nudging of radar radial velocity:results shown last year
control
nudge vr
0-UTC runsTSS
FF-10m RMSE
FF-10m bias, all sta. sta. < 100 m
sta. > 800 m300m < sta < 800m
100m < sta < 300m
These differences were due to
different external parameters !
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 6
nudging of radar radial velocity:verification against radar precipitation
1 – 27 May 2012
assimilation
threshold: 0.1 mm / h
control (COSMO-DE setup, with LHN)use of radial velocity added
FBI
ETS
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 7
threshold:0.1 mm / h
FSS, 11 g.pts. (30 km)
12-UTC forecast
runs
nudging of radar radial velocity:verif. vs. radar precipitation (1 – 27 May 2012)
00-UTC forecast
runs
ETS
control (C-DE setup, with LHN)use of radial velocity added
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 8
threshold:5.0 mm / h
FSS, 11 g.pts. (30 km)
nudging of radar radial velocity:verif. vs. radar precipitation (1 – 27 May 2012)
00-UTC forecast
runs
ETScontrol (C-DE setup, with LHN)
use of radial velocity added
12-UTC forecast
runs
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 9
nudging of radar radial velocity: summary
• nudging of radar radial velocity implemented
• still code problems with reproducibility (some error rel. to MPI communication)
• experiment May 2012 with additional use of vr (control with LHN !) :
small positive impact on (mainly strong) precipitation otherwise neutral no show cases with strong positive impact
• next: fix reproducibility problem, clean up code, check and improve efficiency include in official COSMO version, add few more tests, make it operational
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 10
Status of OPERA
• currently 27 member states with about 160 radar stations
• OPERA Phase 4 : spring 2013 – 2018 • Programme manager Elena Saltikoff (FMI)• User Group established (total 11 p. from NWP, hydrology, biology)
• three 2-D composites are available every 15 minutes:
• current rain rate, sum over last hour, current maximum reflectivity
• Phillipe Lopez (ECMWF) found out:
• quality has increased in 2013 (with Baltrad QC) but is still not sufficient everywhere
• best quality over UK, France, Poland and Germany
• underestimation over southern Europe
• underestimation in snow cases
• lots of spurious ground echoes
• software transforming it to COSMO grids available (Stephan)
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013
ODC composite
12 Aug 2013, 15 UTC
Status of OPERA
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 Ref-Talk 19.09. 2012 Radial Wind Assimilation
Status of OPERA
‘EY composite: Input for LHN at DWD,
4 different storm-dep. Z-R relationships
OPERA DC composite (C-DE domain):
1 Z-R relationship
differences particularly for low precip rates; (erroneous spaital alignment ?)
12 Aug.2013
15 UTC
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 13
Status of OPERA
• 3-D reflectivity and radial wind:
• reflectivity sent by almost all member states,
radial wind only by few(but increasing)
(Courtesy Hidde Leijnse, * indicates max. number)
• HIRLAM already gets access to volume data, but possible also for other consortia
• dissemination of volume data to member states planned for end of 2014 (to be decided: with or without quality information ?)
• discussion about meta data / quality issues are ongoing(e.g. to distinguish ‘zero echo’ – ‘no data’ (compare with raw data))
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 14
Latent Heat Nudging for COSMO-EU
Motivation
•Reanalysis Project of HErZ would like to use LHN also on its larger domainconfiguration (COSMO-CORDEX, x = 7km)
•Does it work ?
Is there a negative interaction between LHN and the deep convection scheme ?
Experiments
•2 periods: Summer: August 2012 (incl. convective cases)
Winter: 1 Nov. – 15 Dec. 2012 (incl. snow cases)
•operational COSMO-EU setup (Cosmo V4_27, tk?min=0.4)
•operational LHN setup except: • no blacklist information used• no bright band detection• LHN within first 25 minutes of forecast (will be ~ 2.5h in operational run)
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013
• same data as for COSMO-DE,
currently•17 German Doppler radar stations
quality controlled•2 Dutch stations•2 Belgian stations•9 France stations•3 Swiss stations•2 Czech stationssoon extended by 2 Polish stations
• every 5 minutes
• future: can be extended by OPERA composite outside COSMO-DE domain
LHN for COSMO-EU:radar data coverage
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013
hourly precipitation at 2 Aug. 2012, 00 UTC + 4h
Radar Control (rout) LHN Experiment
LHN for COSMO-EU:case study
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013
12 UTCLHNROUT
LHN for COSMO-EU:SYNOP verification, summer: positive
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013
00 UTCLHNROUT
LHN for COSMO-EU:SYNOP verification, winter: slightly positive
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013
Experiment ControlBIAS RMSE
LHN for COSMO-EU:TEMP verification, summer / winter: neutral
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013
Assimilation 0.1 mm/hAssimilation 0.1 mm/h
LHNROUT
LHN for COSMO-EU:Verification against radar precip (summer)
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013
12 UTC 0.1 mm/h 12 UTC 2.0 mm/h
00 UTC 2.0 mm/h00 UTC 0.1 mm/h
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013
• LHN in COSMO-EU is beneficial; forecast impact:
• Summer:
• precipitation improved (esp. convective cases)
• most surface parameters improved
• Winter:
• most surface parameter slightly improved
• impact on precipitation and low stratus neutral
• Work started to extend data coverage using OPERA radar composite
LHN for COSMO-EU:Summary
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 23
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 24
nudging of radar radial velocity:verification against radar precipitation
1 – 27 May 2012
precipitation against radar
FSS , 11 g.pts. (30 km)
threshold : 2 mm / h
control (COSMO-DE setup, with LHN)
use of radial velocity added
assimilation
00-UTC forecast runs 12-UTC forecast runs
[email protected] Radial Velocity, OPERA, LHN for COSMO-EUCOSMO GM, Sibiu, 2 September 2013 25
nudging of radar radial velocity:example
radial velocity at lowest elevation (0.5°) of radar site Feldberg (30 Jan. 2012, 21 UTC).
observation
Azimuth
Ran
ge
(in m
)
model (COSMO-DE)
observation increment
Azimuth
Ran
ge
(in m
)
southwesterly wind above 2500 m a.s.l.