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Page 1 © Crown copyright 2005 ECMWF User Meeting, June 2006 Developments in the Use of Short and Medium-Range Ensembles at the Met Office Ken Mylne Ensemble Forecasting Manager
Page 2 © Crown copyright 2005 ECMWF User Meeting, June 2006 Contents First Guess Early Warnings – again! Example of EPS Use for Confidence New Applications of EPS Drought-planning Forecasts Best-Member Project Eurorisk PREVIEW Windstorms MOGREPS – The new Met Office short-range ensemble
First Guess Early Warnings - A confession
Page 4 © Crown copyright 2005 ECMWF User Meeting, June 2006 FGEW Verification – an error Over the last few years we have reported on verification results from our First Guess Early Warnings A key feature was a maximum in skill at 4 days Much discussion and investigation With regret and apologies, I have to report that this result was caused by an error in our verification scheme Misalignment of forecast times with verifying times in the verification database Day 4 was correctly aligned, other days wrong
Page 5 © Crown copyright 2005 ECMWF User Meeting, June 2006 Corrected Verification - ROC With the bug corrected the verification shows a near- constant ROC area for days 1-4 of the forecast with a slow decline from day 5 or 6.
Page 6 © Crown copyright 2005 ECMWF User Meeting, June 2006 Corrected Verification - Reliability Reliability diagrams show useful resolution at 2 and 4 days.
Page 7 © Crown copyright 2005 ECMWF User Meeting, June 2006 Corrected Verification – Cost-loss Cost-loss curves show slow reduction in values at longer lead times Largest effect for large C/L ratios Increasing chance of capturing event at high probability
Example of EPS Use for Confidence
Page 9 © Crown copyright 2005 ECMWF User Meeting, June 2006 Example – low spread, high confidence Cold period in November 06 with snow in SW ECMWF EPS gave very high confidence of blocking breakdown Allowed issue of high confidence of return to mild conditions on Wed 30 th 5 days ahead Analysis of 0600 on 30 th confirms this was correct
New Applications of EPS - i) Drought Planning Forecasts
Page 11 © Crown copyright 2005 ECMWF User Meeting, June 2006 Drought planning forecasts Probabilities for 10-day rainfall totals Mod-High probability of below normal Only low risk of very dry (<5mm in 10 days) in SE England
New Applications of EPS - ii) Best Member Project
Page 13 © Crown copyright 2005 ECMWF User Meeting, June 2006 Integrating Ensembles into Operations We would like to make all forecasts probabilistic BUT Met Office customers still demand a best-estimate deterministic forecast Currently use field modification Link UK GM at T+36 with preferred solution later Can we choose an ensemble Best Member? Best fit to preferred solution, or Ensemble Mean? Representative member of largest cluster? Best Member could give: Dynamically consistent forecast at all times Full set of consistent model fields
Page 14 © Crown copyright 2005 ECMWF User Meeting, June 2006 Best Member project Project being run with Operations Centre to test: Can we identify a suitable Best Member? How long does a good EPS member stay good? Can we re-calculate probabilities? Expect BM selected for mesoscale may be different from that for synoptic scale/medium range forecasts. Use error tracking to identify source regions Consider short and medium ranges separately, using MOGREPS and EC EPS respectively.
New Applications of EPS - iii) Eurorisk PREVIEW Windstorms
Page 16 © Crown copyright 2005 ECMWF User Meeting, June 2006 Ensemble Forecasts PEACE (MeteoFrance) SRNWP-PEPS (DWD) LAMEPS (Met.no) ECMWF EPS (ECMWF) MOGREPS ( Met Office UK) COSMO-LEPS Eurorisk PREVIEW Windstorms Database (Met Office UK) Kalman Filter Wind Gust Calculation (Meteo-France) Windstorm Forecast Products Website (Met Office UK) Risk Mapping Data (SMHI) Windstorm Risk Mapping Products Multi-model ensemble forecasts for Windstorm Risk Adapted existing site-specific database tables for additional ensembles 196 sites across 9 countries
Page 17 © Crown copyright 2005 ECMWF User Meeting, June 2006 Products Traffic light maps for initial alerts Site-specific details: Meteograms Wind-roses Eurorisk PREVIEW Windstorms
Page 18 © Crown copyright 2005 ECMWF User Meeting, June 2006 Eurorisk PREVIEW Windstorms Alert thresholds will be a combination of probability and severity, eg. Severity (Climate Percentile) 90%95%99%99.9% Prob>80% 50-80% 20-50% 1-20% Thresholds referenced to site climates Analysed from ERA40 Calibrated using site observations
MOGREPS – Met Office Global and Regional EPS
Page 20 © Crown copyright 2005 ECMWF User Meeting, June 2006 MOGREPS – The Met Office short-range Ensemble Ensemble designed for short-range Regional ensemble over N. Atlantic and Europe (NAE) Nested within global ensemble ETKF perturbations Stochastic physics T+72 global, T+36 regional Aim to assess uncertainty in short-range, eg.: Rapid cyclogenesis Local details (wind etc) Precipitation Fog and cloud NAE MOGREPS is on Operational Trial for 1 year from September 2005
Page 21 © Crown copyright 2005 NWP Seminar 3 rd Feb 2006 T+12 perturbed forecast T+12 ensemble mean forecast ( - ) + = Transform matrix Control analysis Perturbed analysis 0.9 Pert Pert Pert Pert Pert 5 Ensemble Transform Kalman Filter (ETKF)
Page 22 © Crown copyright 2005 NWP Seminar 3 rd Feb 2006 Stochastic Convective Vorticity (SCV) Unresolved impact of organised convection (MCSs) Not used in the higher resolution regional ensemble Random Parameters (RP) Structural error due to tuneable parameters Stochastic Kinetic Energy Backscatter (SKEB) Similar to ECMWF CASBS scheme Excess dissipation of energy at small scales SKEB implemented in global ensemble in PS11 Stochastic schemes for the UM Impact is propagated to next cycle through the ETKF!
Page 23 © Crown copyright 2005 ECMWF User Meeting, June 2006 Display system
Page 24 © Crown copyright 2005 ECMWF User Meeting, June 2006 Products – Postage stamps
Page 25 © Crown copyright 2005 ECMWF User Meeting, June 2006 Products – Probability charts
Page 26 © Crown copyright 2005 ECMWF User Meeting, June 2006 MOGREPS Site-specific forecasts EPS Meteograms MOGREPS Plume Kalman filter MOS is being implemented for MOGREPS forecasts
Page 27 © Crown copyright 2005 NWP Seminar 3 rd Feb 2006 Verification Verification to date is very basic Verification is being implemented within the Area-based Verification system (ABV) and Site-specific Verification system (SBV) Verification performed over NAE area for forecasts from global ensemble Performed (except where stated) against analysis For 111 cycles between 17/10/05 and 9/1/06
Page 28 © Crown copyright 2005 NWP Seminar 3 rd Feb hPa height – spread and RMSE Spread optimised by variable inflation factor against observations in u, v, T and RH at T+12 Appears too large because verified against analysis (tbc) Ensemble mean skill does not currently improve on control skill Spread and RMSE for 500hPa GPH
Page 29 © Crown copyright 2005 NWP Seminar 3 rd Feb hPa height – rank histogram Rank histogram is encouragingly flat Close to ideal Suggests that ETKF perturbations are representative of genuine analysis errors This performance seems much improved on ECMWF ensemble Rank Histogram at T+72 for 500hPa GPH Solid – operational, Dotted – PS11 upgrade
Page 30 © Crown copyright 2005 ECMWF User Meeting, June 2006 Verification - T+36 6hr total > 0.5mm Global EnsembleRegional Ensemble
Page 31 © Crown copyright 2005 ECMWF User Meeting, June 2006 Verification - T+36 6hr total > 5mm Global EnsembleRegional Ensemble
Page 32 © Crown copyright 2005 ECMWF User Meeting, June 2006 Verification - T+36 6hr total > 0.5mm Global Ensemble GlobalRegional
Page 33 © Crown copyright 2005 ECMWF User Meeting, June 2006 Conclusions FGEW verification resolved! EPS continues to become more integrated in forecasting procedures First-choice for new services (eg drought planning) How to produce best deterministic forecast? Basis of new risk-management services for EU MOGREPS provides a promising new short- range ensemble capability complements EPS for medium-range
Page 1© Crown copyright 2005 Use of EPS at the Met Office Ken Mylne and Tim Legg.
© Crown copyright Met Office Recent & planned developments to the Met Office Global and Regional Ensemble Prediction System (MOGREPS) Richard Swinbank,
Page 1© Crown copyright Operational Use of ECMWF products at the Met Office: Current practice, Verification and Ideas for the future Tim Hewson 17 th June.
Slide 1 Forecast Products User Meeting June 2006 Summary Forecast Products User Meeting: June 2006 Summary.
Page 1© Crown copyright Some Strengths and Weaknesses of ECMWF Forecasts for the UK Tim Hewson 15 th June 2006 Contributors include: Eleanor Crompton,
Page 1© Crown copyright 2004 Presentation to ECMWF Forecast Product User Meeting 16th June 2005.
ECMWF Slide 1Met Op training course – Reading, March 2004 Forecast verification: probabilistic aspects Anna Ghelli, ECMWF.
Slide 1 Forecast Products User Meeting June 2006 Slide 1 ECMWF medium-range forecasts and products David Richardson Met Ops.
Page 1© Crown copyright 2004 ECMWF Forecast Products Users Meeting 15th June 2006.
HB 1 Forecast Products Users'Meeting, June 2005 Users meeting Summary Performance of the Forecasting System (1) Main (deterministic) model -Outstanding.
Training Course 2009 – NWP-PR: The Seasonal Forecast System at ECMWF 1 The Seasonal Forecast System at ECMWF Tim Stockdale European Centre for Medium-Range.
© Crown copyright Met Office Investigating a perturbed physics scheme in a wave ensemble system Ray Bell (Line manager: Francois-Bocquet) Ocean Iced Tea.
Slide 1 ECMWF Data Assimilation Training Course – May 2010 Ensemble Data Assimilation Massimo Bonavita ECMWF Acknowledgments: Lars Isaksen, Elias Holm,
ECMWF User Meeting / 1 Pertti Nurmi Juha Kilpinen Annakaisa Sarkanen ( Finnish Meteorological Institute ) Probabilistic Forecasts.
Training Course 2009 – NWP-PR: Calibration of EPSs 1/42 Calibration of EPSs Renate Hagedorn European Centre for Medium-Range Weather Forecasts.
© Crown copyright Met Office Use of Ensembles in Variational Data Assimilation DAOS WG. Sept Andrew Lorenc.
The THORPEX Interactive Global Ensemble (TIGGE) Multi-model ensembles and Tropical cyclone forecasting Richard Swinbank, with thanks to the GIFS-TIGGE.
Page 1© Crown copyright 2005 Met Office seasonal predictions and applications Richard Graham Chris Gordon, Matt Huddleston, Mike Davey, Alberto Arribas,
F. Prates Data Assimilation Training Course April Error Tracking F. Prates.
Forecast users meeting Reading, June 2005 ECMWF medium range forecasts and products Model changes (Medium Range) Forecast performance New products/
ECMWF Forecast Products User Meeting, E. Zsoter, June 2006 Severe Weather Forecasts Severe Weather Forecasts Ervin Zsoter.
Page 1© Crown copyright 2004 Seasonal forecasting activities at the Met Office Long-range Forecasting Group, Hadley Centre Presenter: Richard Graham ECMWF.
Ensemble Prediction Systems and Probabilistic Forecasting Richard (Rick) Jones SWFDP Training Workshop on Severe Weather Forecasting Bujumbura, Burundi,
Seasonal forecasting: status and plans David Anderson Tim Stockdale, Magdalena Balmasda, Arthur Vidard, Alberto Troccoli, Paco Doblas-Reyes, Kristian Morgensen,
ECMWF Stochastic representations of model uncertainty: Glenn Shutts March 2009 Stochastic representations of model uncertainty Glenn Shutts ECMWF/Met Office.
The COSMO-LEPS system at ECMWF Chiara Marsigli, Andrea Montani, Tiziana Paccagnella ARPA-SIM, Bologna, Italy.
ECMWF Training course 2010 slide 1 Towards an adaptive observation network: monitoring the observations impact in ECMWF forecast Carla Cardinali Office.
Slide 1 Predictability training course 2013, EPS applications: Droughts © ECMWF Applications of the EPS: Droughts Emanuel Dutra
© Crown copyright Met Office Met Office progress report Andy Brown WGNE, Tokyo, October 2010.
1 Development of the deterministic forecast system (June 2006) Martin Miller (Head of Model Division) with input from many colleagues.
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