WGNE report. Jean Noël Thépaut & Ayrton Zadra. WGNE co chairs. Working Group on Numerical Experimentation

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1 WGNE report Jean Noël Thépaut & Ayrton Zadra WGNE co chairs ECMWF 1 Role of WGNE Working Group on Numerical Experimentation Jointly established by the WCRP and the WMO Commission for Atmospheric Sciences (CAS) Responsibility of fostering the development of atmospheric circulation models for use in weather prediction and climate studies on all time scales and diagnosing and resolving shortcomings. What we do, in a nutshell Advice, liaison Co ordinated experiments Workshops, publications, meetings ECMWF 2 Page 1

2 ECMWF 3 Co ordinated projects and experiments Transpose AMIP testing climate models in weather mode Grey zone representation of cold air outbreaks at different resolutions Verification NWP performance (eg TCs, precipitation) Polar (CBS style; ConcordIASI intercomparison) PPP Climate metrics Issues with verification against own analysis MJO / Boreal Summer Intraseasonal Oscillation intercomparisons and forecast metrics (MJO TF) S2S Comparison of model momentum budgets how do they differ? What is right? Importance of aerosols for weather and climate assessing the level of complexity required ECMWF 4 Page 2

3 Transpose AMIP (co sponsored by WGCM) K. Williams ECMWF 5 Transpose AMIP (co sponsored by WGCM) K. Williams ECMWF 6 Page 3

4 Transpose AMIP (co sponsored by WGCM) K. Williams ECMWF 7 GASS Grey Zone project [from report by J. Petch presented at WGNE-30] Motivation Most operational models are in or approaching the Grey Zone We do not know how to parameterize overturning related processes in the Grey Zone Yet it is these processes (clouds, turbulence, convection) that are key for weather and climate. ECMWF 8 Page 4

5 GASS Grey Zone project [from report by J. Petch presented at WGNE-30] Objectives Show how faithfully fluxes, variances, cloud structures, etc. can be represented Guide improvements in current schemes. Gain some insight and understanding of what can (and what cannot/should not) be done without parametrizations. Explore the importance/relevance of stochastic parameterizations. Ultimately provide guidance for the design of scale aware parameterizations. An extra-tropical case Cold-air outbreaks are of general interest for various communities Proposal: Constrain cold-air outbreak experiment 31 January 2010 Full case description see: ECMWF 9 GASS Grey Zone project [from report by J. Petch presented at WGNE-30] 1 st Grey Zone Workshop MPI for Meteorology, Hamburg, Germany Dec 2014 Some early conclusions LAM & LES reproduce the breakup of the Scu into the Cu very well Global Models (despite a similar resolution) show a poorer performance Microphysics does has a strong influence on the results Switching on/off the convection scheme at O(1km) resolution has different impact depending on model Area averaged metrics (LW, SW) do not vary greatly with changed resolution, despite the fact that the used parametrizations are not explicitly scale-aware formulated. Quite a bit to do but could move to new case in parallel ECMWF 10 LWP+IWP from 3 participating global models Page 5

6 GASS Grey Zone project [from report by J. Petch presented at WGNE-30] Next Steps April Sept 2015: Analysis and wrap up case Oct-Dec 2015: Reporting in peer reviewed journals ( 1 LES-paper / 2 combine GCM/LAM papers & one overview paper ). Discussion is open for a next case (Preferred one which is addressing deeper convection). This could be based on an already existing case -- with right volunteers it might be time to move to the tropics ECMWF 11 OLR from 6 participating Limited Area European Centre for Medium Range Weather Models Forecasts at ~ 1km resolution. Objective WGNE Aerosols project [S. Freitas] Evaluate the impact of aerosols on Numerical Weather Prediction Approach Select events of aerosol pollution Perform model runs with and without feedback from the aerosol interaction with radiation and clouds. Evaluate aerosol simulation of AOD (aerosol optical depth) or related parameter Evaluate aerosol impact on meteorology (2 meter temperature, dew point temperature, 10 meter wind, rainfall, surface energy budget, etc.) ECMWF 12 Case 2 Pollution over China -- SW Radiation at Surface Impact: difference European Centre for Medium Range Weather between Forecasts Aero and NoAero runs from 4 participating models Page 6

7 WGNE Aerosols project [S. Freitas] ECMWF 13 3 strong or persistent events of aerosol pollution that could be fairly represented European in the Centre current for Medium Range NWP models Weather Forecasts WGNE Aerosols project [S. Freitas] ECMWF 14 Page 7

8 WGNE Aerosols project [S. Freitas] Ongoing work Establish database and web platform for model assessment and comparison against observations. WGNE data sets: standard format was defined (to conform with EuMetChem's); data to be converted to standardized NetCDF. Meteo station data format being converted to a format compatible with CPTEC's GrADS Online Looking into OpenDAP/GDS to supply simulation data and meta-information to the public Next steps Perform data evaluation Produce a report and a paper Second phase? (seasonal ECMWF 15 timescales) Merge/collaborate with other activities? MICS (Model Intercomparison Study Asia phase III) suggested a meeting suggested to integrate European Centre for Medium Range the Weather initiatives Forecasts (e.g. GAW/WGNE) WGNE Drag Project [A. Zadra] Main goal: compare the parametrized or physics component of this surface stress, i.e. the stress from parametrizations such as the planetary boundary layer (PBL) and the subgrid orographic (SGO) schemes. Basic output requested: x- and y-components of the parametrized stress, in units of N/m2, averaged over the 1st day (24h) of a month of forecasts. The months proposed were Jan and Jul ECMWF 16 Page 8

9 WGNE Drag Project [A. Zadra] ICON 15km DWD pbl, sgo, res ECMWF 17 WGNE DRAG project inter comparison of stress fields IFS (ECMWF) UM (UKMetO) u-component of PBL stress (N/m2) Jan h average ECMWF 18 Page 9

10 WGNE Drag Project Recent developments, ongoing and planned activities Website and 1 st report submitted to participants Concept paper in preparation (to be submitted to BAMS) Results presented at 21 st Symposium on Boundary Layer and Turbulence (Jun 2014, Leeds, UK) World Weather Open Science Conference (Aug 2014, Montreal, Canada) Workshop on Angular Momentum Budget (April 2015 at Univ. Reading, organized by Dr. T. Shepherd) Julio Bacmeister is WGNE s contact with climate community Proposed session on momentum-related issues at next Systematic Errors Workshop (date & location to be determined) ECMWF to organize a workshop in 2016 (Irina Sandu) ECMWF 19 GEWEX/SPARC/WGNE workshop on Drag processes and their links to large-scale circulation ECMWF, Reading, UK, 12th-16th September 2016 Programme Committee Co-chairs: Irina Sandu (ECMWF) and Felix Pithan (University of Reading) Julio Bacmeister (NCAR) Andreas Dörnbrack (DLR) Ted Shepherd (University of Reading) Gunilla Svensson (MISU) Ayrton Zadra (Environment Canada) Aim: to assess the current state of our understanding of drag processes and their impact on the large-scale circulation on timescales ranging from numerical weather prediction to climate Thematic axes Underlying processes and sources of inter-model spread in the WGNE Drag Project Ground truth through observations and fine-scale modelling Representation of drag across scales: What are the implications of increasing resolution? Impact of uncertainty associated with drag in NWP and climate models Interpretation of tendencies/increments from NWP analysis and reanalysis ECMWF 20 Page 10

11 MJO Task Force Joined WGNE 2years ago, Continues to make progress towards its overall goal to facilitate improvements of the MJO in weather and climate models. 6 current subprojects: 1. Process oriented diagnostics/metrics for MJO simulation 2. Boreal summer monsoon ISV monitoring and forecast metrics 3. Assessment of CMIP5 model capability to simulate realistic intraseasonal variability 4. MJO TF + GASS Multi Model Diabatic Processes Experiment 5. MJO air sea interaction 6. The MJO and the Maritime Continent (with S2S). ECMWF 21 MJO TF activities J. Gottschalck ECMWF 22 Page 11

12 Future directions Short-range weather prediction Changing focus cloud, rain, surface temperature (not Z500!) Increased emphasis on high resolution especially convection permitting 25km Grey-zone project Appropriate metrics for high resolution models (with JWGVR) and routine use of them Link to climate downscaling? 1.5km ECMWF 23 Future directions Earth system prediction (Ensemble) atmospheric weather prediction models coupled to ocean, composition, air quality, hydrology, ice... Time evolution of coupled model SST errors Bringing together communities (GODAE/DAOS/WGNE coupling modelling and assimilation workshop Spring 2016) Importance of aerosol for NWP: review and test cases, extend timescales TRANSPOSE-CMIP? ECMWF 24 Page 12

13 Future directions Traditional model evaluation and development Still important and importance underrecognized Champion (with partners) e.g. Conferences Specific projects to engage community and tackle key issues Coordinate verification activities: WGNE/WGCM metrics panel, JWGVR) ECMWF 25 Future directions: short term focus and immediate actions Comparison of model momentum budgets Consolidate results, engage with more participants Define way forward, publish, workshop (2016) Importance of aerosols for weather and climate Expand cases, refine protocols, expand beyond NWP angle, etc. Support to S2S Systematic error workshop, special focus on teleconnections, workshop (2017) Support to PPP (PCPI) Verification (quality of (re )analyses), observational system design, etc. Support to CMIP High resolution time slice intercomparisons ECMWF 26 Page 13

14 Thank You ECMWF 27 Page 14