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High-resolution Regional Reanalyses for Europe and Germany Christian Ohlwein1,2, Jan Keller1,4, Petra Friederichs2, Andreas Hense2, Susanne Crewell3, Sabrina Bentzien1,2, Christoph Bollmeyer1,2, Jessica Keune1,2, Ieda Pscheidt1,2, Stephanie Redl1,3, Sandra Steinke1,3, David Willms1,2 1 Hans-Ertel-Centre for Weather Research – Climate Monitoring Branch 2 Meteorological Institute, University of Bonn 3 Institute for Geophysics and Meteorology, University Cologne 4 Deutscher Wetterdienst DWD In cooperation with Stefan Kollet6,7, Mauro Sulis6 6 Meteorological Institute, University of Bonn 7 Institute for Bio- and Geosciences, Agrosphere (IBG-3), Research Centre Jülich
DMG-‐Kolloquium, Berlin, 20 January 2014
Approach è Build up a regional reanalysis system
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Objective è Develop methods for monitoring regional climate for
operational use at the DWD § Synthesis of heterogeneous observations § High resolution in space and time § Assessment of uncertainty
Outline è Towards a regional reanalysis system
§ Set-up and characteristics § Evaluation
è Perspectives § Next steps and new approaches
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Atmospheric Reanalyses
è Data assimilation with a physical model § Synthesize heterogeneous monitoring networks § Provide four-dimensional fields
§ Physically consistent in space and time and between variables § Unobserved variables
è Alternative concepts § Spatio-temporal interpolation § Dynamical downscaling from global reanalyes § …
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Observations Data Assimilation Physical Model
Atmospheric Reanalyses
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Current reanalyses ERA-Interim ECMWF T255 L60 1989-present
ERA-40 ECMWF T159 L60 1958-2001
Japanese Reanalysis (JRA-25) JMA T106 L40 1979-2004
NCEP Reanalysis AMIP-II (R2) NCEP T62 L28 1979-present
NCEP Reanalysis I (R1) NCEP T62 L28 1948-present
MERRA NASA 0.5° x 0.5° 1979-2010
Climate Forecast System Reanalysis (CFSR) NCEP T382 L64 1979-????
20th Century Reanalysis (20CR) NOAA T62 L28 1871-2008
North American Regional Reanalysis (NARR) NCEP 32 km 1979-present
Arctic System Reanalysis (ASR) PMG 10-20 km 2000-2010 www.reanalysis.org
Regional Reanalyses
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
COSMO-REA2 COSMO-DE (2 km)
Regional Reanalysis System
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Continuous nudging SYNOP, SHIP, PILOT, TEMP, AIREP, AMDAR, ACARS,…
SST analysis (daily) Snow analysis (6-hourly)
COSMO-REA6 (6.2 km)
§ CORDEX EUR-11 domain § Data assimilation …
ERA-Interim Reanalysis (T255)
Soil moisture analysis (SMA)
COSMO-REA2 (2.0 km)
§ COSMO-DE domain § Data assimilation … Latent heat nudging (LHN)
Continuous nudging SYNOP, SHIP, PILOT, TEMP, AIREP, AMDAR, ACARS,…
SST analysis (daily) Snow analysis (6-hourly)
Soil moisture analysis (SMA)
Latent heat nudging (LHN)
Regional Reanalysis System
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
COSMO-DS6 (6.2 km)
§ CORDEX EUR-11 domain § Downscaling only
ERA-Interim Reanalysis (T255)
Model Output è Domain
§ REA6: 848 × 824 grid points § REA2: … × … grid points
è Variables § ≈ 150 fields (2D/3D) § Output interval
§ 60 min (3D) § 15 min (2D)
è Status § COSMO-REA6: 5 years (2007–2011) § COSMO-REA2: Selected months…
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
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i=1 i=2 i=3 i=4
i=1
i=2
i=3
i=4
i=1 i=2 i=3 i=4 i=5 i=6 i=7 i=8
j=1
j=2
j=3
j=4
j=5
j=6
j=7
j=8
Setup B (equal volumes)
CO
SM
O-R
EA
6
CO
RD
EX
EU
R-1
1
Outline è Towards a regional reanalysis system
§ Set-up and characteristics § Evaluation
è Perspectives § Next steps and new approaches
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Model Output (REA6/DS6)
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
IQ D
ISTA
NCE
[mm
/3h]
DJF
0.00
0.04
0.08
JJA
03 06 09 12 15 18 21 00UTC
0.00
0.04
0.08
0.12
0.16
ERA-INTERIMCOSMO-DSCOSMO-REA6
Precipitation – Distribution
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
*) cf. Thorarinsdottir et al. (2013): Using proper divergence functions to evaluate climate models
Integrated Quadratic Distance* (IQD) COSMO-CORDEX / German SYNOP stations (2011)
Precipitation – Extremes
<0.1 0.1−1.0 1.0−5.0 5.0−10.0 >10.00.0
0.5
1.0
1.5
2.0
2.5
Precipitation [mm/3h]
Occ
uren
ces
[x10
6 ]
SYNOPCOSMO−REACOSMO−DSERA−INTERIM
20−30 30−40 40−50 50−60 >600.0
0.2
0.4
0.6
0.8
1.0
Precipitation [mm/3h]
Occ
uren
ces
[x10
3 ]
SYNOPCOSMO−REACOSMO−DSERA−INTERIM
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Histogram of 3-hourly precipitation events at German SYNOP stations (COSMO-REA6/DS6 simulations, 2011)
*) note the change of support
* * 6
6 6
6
Precipitation – Log-Odds Ratio
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Log-odds ratio for 3-hourly precipitation events compared to German SYNOP stations (COSMO-REA6 simulations, 2011)
6 6
Model Output (REA6/REA2)
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Precipitation – Extremes
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Histogram of 3-hourly precipitation events at German SYNOP stations (June–August 2011)
*) note the change of support
* *
Precipitation – Diurnal Cycle
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Mean precipitation intensities (>0.1 mm/h) at German SYNOP stations (June–August 2011)
What is a “good” reanalysis? – Difficult to answer…
Further Evaluation è Standard evaluation
§ Analysis increments § Water and energy cycle § …
è Remote sensing data
§ AMSU-B Microwave Humidity Sensor § MSG brightness temperature § IWV from GNSS measurements § Ceilometer measurements § …
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Further Evaluation – Clouds
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Brightness temperature (10.8 µm) – COSMO-REA (LHN test runs at 2.8 km)
Further Evaluation – Frozen Hydrometeors
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
AMSU-B COSMO-REA6
Outline è Towards a regional reanalysis system
§ Set-up and characteristics § Evaluation
è Perspectives § Next steps and new approaches
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Next steps
è Time slots in the past § COSMO-REA6: 1979–1983, … § COSMO-REA2: one year within the RADAR period
è Start operational use at DWD
§ COSMO-REA6 planned to become operational in mid/late 2014
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Next steps è Assimilation of rain gauge
measurements § Disaggregation
§ Rain gauge measurements § Covariates such as MSG TB
§ Assimilation via LHN § Prerequisite for long-term
runs of COSMO-REA2
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
3 August 2007, 02–03 UTC
New approaches
è UERRA: Uncertainties in Ensembles of Regional Re-Analysis § Multi-model ensembles § EU FP7-SPACE: 12 European partners (EURO4M consortium) § HErZ: Ensemble data assimilation
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Hybrid LETKF/ensemble nudging
New approaches è Enhanced representation of soil-vegetation-atmosphere processes
§ Integrated modeling system TerrSysMP (ParFlow-CLM3.5-COSMO)
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Shrestha et al. (2012)
New approaches è Enhanced representation of soil-vegetation-atmosphere processes
§ Integrated modeling system TerrSysMP (ParFlow-CLM3.5-COSMO)
è Status § Drainage test on CORDEX EUR-11
è Synergies § TR32 and Geoverbund ABC/J § Planned CRC TerraWatt
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Outline è Towards a regional reanalysis system
§ Set-up and characteristics § Evaluation
è Perspectives § Next steps and new approaches
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
Summary è Towards a high-resolution regional reanalysis system
§ Current status § COSMO-REA6 (6.2 km): 2011 and 2007–2011 § COSMO-REA2 (2.0 km): Jun–Aug 2011
§ Multi-parameter evaluation
§ Representation of spatio-temporal variability § Coherence between model and independent observations
è Perspectives § Ensemble data assimilation methods § Enhanced representation of soil-vegetation-atmosphere processes
Christian Ohlwein ■ Hans-Ertel-Centre for Weather Research ■ Climate Monitoring Branch
High-resolution Regional Reanalyses for Europe and Germany Christian Ohlwein1,2, Jan Keller1,4, Petra Friederichs2, Andreas Hense2, Susanne Crewell3, Sabrina Bentzien1,2, Christoph Bollmeyer1,2, Jessica Keune1,2, Ieda Pscheidt1,2, Stephanie Redl1,3, Sandra Steinke1,3, David Willms1,2 1 Hans-Ertel-Centre for Weather Research – Climate Monitoring Branch 2 Meteorological Institute, University of Bonn 3 Institute for Geophysics and Meteorology, University Cologne 4 Deutscher Wetterdienst DWD In cooperation with Stefan Kollet6,7, Mauro Sulis6 6 Meteorological Institute, University of Bonn 7 Institute for Bio- and Geosciences, Agrosphere (IBG-3), Research Centre Jülich
DMG-‐Kolloquium, Berlin, 20 January 2014
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