High-resolution Regional Reanalyses for Europe and Germany Christian Ohlwein 1,2, Jan Keller 1,4, Petra Friederichs 2, Andreas Hense 2, Susanne Crewell 3, Sabrina Bentzien 1,2, Christoph Bollmeyer 1,2, Jessica Keune 1,2, Ieda Pscheidt 1,2, Stephanie Redl 1,3, Sandra Steinke 1,3, David Willms 1,2 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 Kollet 6,7, Mauro Sulis 6 6 Meteorological Institute, University of Bonn 7 Institute for Bio- and Geosciences, Agrosphere (IBG-3), Research Centre Jülich DMG- Kolloquium, Berlin, 20 January 2014
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 Approach è Build up a regional reanalysis system
Outline è Towards a regional reanalysis system Set-up and characteristics Evaluation è Perspectives Next steps and new approaches
Atmospheric Reanalyses Observations Data Assimilation Physical Model 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
Atmospheric Reanalyses 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 COSMO-REA2 COSMO-DE (2 km)
Regional Reanalysis System ERA-Interim Reanalysis (T255) COSMO-REA6 (6.2 km) CORDEX EUR-11 domain Data assimilation COSMO-REA2 (2.0 km) COSMO-DE domain Data assimilation Soil moisture analysis (SMA) Continuous nudging SYNOP, SHIP, PILOT, TEMP, AIREP, AMDAR, ACARS, SST analysis (daily) Snow analysis (6-hourly) Latent heat nudging (LHN)
Regional Reanalysis System ERA-Interim Reanalysis (T255) COSMO-DS6 (6.2 km) CORDEX EUR-11 domain Downscaling only Soil moisture analysis (SMA) Continuous nudging SYNOP, SHIP, PILOT, TEMP, AIREP, AMDAR, ACARS, SST analysis (daily) Snow analysis (6-hourly) Latent heat nudging (LHN)
Model Output Setup B (equal volumes) i=1 i=2 i=3 i=4 i=5 i=6 i=7 i=8 è Domain REA6: 848 824 grid points REA2: grid points i=4 j=8 j=7 è Variables 150 fields (2D/3D) Output interval 60 min (3D) 15 min (2D) CORDEX EUR-11 i=3 i=2 i=1 j=6 j=5 j=4 j=3 j=2 j=1 COSMO-REA6 è Status COSMO-REA6: 5 years (2007 2011) COSMO-REA2: Selected months i=1 i=2 i=3 i=4
Outline è Towards a regional reanalysis system Set-up and characteristics Evaluation è Perspectives Next steps and new approaches
Model Output (REA6/DS6)
Precipitation Distribution 0.08 DJF COSMO-REA6 COSMO-DS ERA-INTERIM Integrated Quadratic Distance* (IQD) COSMO-CORDEX / German SYNOP stations (2011) 0.04 IQ DISTANCE [mm/3h] 0.00 0.16 0.12 0.08 JJA 0.04 0.00 03 06 09 12 15 18 21 00 UTC *) cf. Thorarinsdottir et al. (2013): Using proper divergence functions to evaluate climate models
Precipitation Extremes 2.5 2.0 1.0 SYNOP SYNOP COSMO REA6 COSMO REA6 COSMO DS6 COSMO DS6 ERA INTERIM* 0.8 ERA INTERIM* Occurences [x10 6 ] 1.5 1.0 Occurences [x10 3 ] 0.6 0.4 0.5 0.2 0.0 <0.1 0.1 1.0 1.0 5.0 5.0 10.0 >10.0 Precipitation [mm/3h] 0.0 20 30 30 40 40 50 50 60 >60 Precipitation [mm/3h] Histogram of 3-hourly precipitation events at German SYNOP stations (COSMO-REA6/DS6 simulations, 2011) *) note the change of support
Precipitation Log-Odds Ratio 6 6 Log-odds ratio for 3-hourly precipitation events compared to German SYNOP stations (COSMO-REA6 simulations, 2011)
Model Output (REA6/REA2)
Precipitation Extremes * * Histogram of 3-hourly precipitation events at German SYNOP stations (June August 2011) *) note the change of support
Precipitation Diurnal Cycle Mean precipitation intensities (>0.1 mm/h) at German SYNOP stations (June August 2011)
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 What is a good reanalysis? Difficult to answer
Further Evaluation Clouds Brightness temperature (10.8 µm) COSMO-REA (LHN test runs at 2.8 km)
Further Evaluation Frozen Hydrometeors AMSU-B COSMO-REA6
Outline è Towards a regional reanalysis system Set-up and characteristics Evaluation è Perspectives Next steps and new approaches
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
Next steps è Assimilation of rain gauge measurements Disaggregation Rain gauge measurements Covariates such as MSG T B Assimilation via LHN Prerequisite for long-term runs of COSMO-REA2 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 Hybrid LETKF/ensemble nudging
New approaches è Enhanced representation of soil-vegetation-atmosphere processes Integrated modeling system TerrSysMP (ParFlow-CLM3.5-COSMO) 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
Outline è Towards a regional reanalysis system Set-up and characteristics Evaluation è Perspectives Next steps and new approaches
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
High-resolution Regional Reanalyses for Europe and Germany Christian Ohlwein 1,2, Jan Keller 1,4, Petra Friederichs 2, Andreas Hense 2, Susanne Crewell 3, Sabrina Bentzien 1,2, Christoph Bollmeyer 1,2, Jessica Keune 1,2, Ieda Pscheidt 1,2, Stephanie Redl 1,3, Sandra Steinke 1,3, David Willms 1,2 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 Kollet 6,7, Mauro Sulis 6 6 Meteorological Institute, University of Bonn 7 Institute for Bio- and Geosciences, Agrosphere (IBG-3), Research Centre Jülich DMG- Kolloquium, Berlin, 20 January 2014