1. 1 Research activities Climate Services & NCCR Christof Appenzeller et al. Eidgenössisches Departement des Innern EDI Bundesamt für Meteorologie und Klimatologie MeteoSchweiz Research Activities in the Climate Services at MeteoSwiss Federal Office of Meteorology and Climatology MeteoSwiss Christof Appenzeller Michael Begert, Paul Della-Marta, Christoph Frei, Heike Kunz, Mark Liniger, Simon Scherrer, Andreas Weigel, Christian Wüthrich www.meteoschweiz.admin.ch

2. 2 Research activities Climate Services & NCCR Christof Appenzeller et al. Research activities Climate Services (KD) Federal Office of Meteorology and Climatology MeteoSwiss Christof Appenzeller Michael Begert, Christoph Frei, Heike Kunz, Mark Liniger, Simon Scherrer, Andreas Weigel, Christian Wüthrich www.meteoschweiz.admin.ch

3. 3 Research activities Climate Services & NCCR Christof Appenzeller et al. Neue Zürcher Zeitung, 10. August 2007 Quelle: MeteoSchweiz Climate Services products …..

4. 4 Research activities Climate Services & NCCR Christof Appenzeller et al. Eidgenössisches Departement des Innern EDI Bundesamt für Meteorologie und Klimatologie MeteoSchweiz Tasks Climate Services MeteoSwiss To provide reliable weather and climate data and analyses products for the public, government, politics and business, yesterday, today and tomorrow

5. 5 Research activities Climate Services & NCCR Christof Appenzeller et al. KDdmKDdsKDkaKDki Deborah v Geijtenbeek Verena Felix

6. 6 Research activities Climate Services & NCCR Christof Appenzeller et al. Temperature (mean, min, max) Precipitation Sunshine duration Air pressure (partly) Project DigiHom Digitalisation and homogenisation of long term climate series in Switzerland Swiss National Basic Climatological Network (Swiss NBCN) Annual temperature of Basel 1755-2007 Begert et al., 2005 HOMOGENEOUS TEMPERATURE AND PRECIPITATION SERIES OF SWITZERLAND FROM 1864 TO 2000, Int. J. Climatol. 25: 65–80 Begert 2009, to appear.

7. 7 Research activities Climate Services & NCCR Christof Appenzeller et al. EU FP6 ENSEMBPLES WP 5.1: Development of a daily high-resolution gridded observational dataset for Europe precipitation 1960-2004Tmin 1960-2004 Contribution of MeteoSwiss: automated detection procedure for discontinuities in large data sets number of inhomogeneities detected: 0( ), 1( ), 3( ), 4( ), undefined ( ) Begert, M., E. Zenklusen, C. Häberli, C. Appenzeller, L. Klok, 2008, to appear in Met. Zeitschrift.

8. 8 Research activities Climate Services & NCCR Christof Appenzeller et al. Re-Analysis ERA40 & observations Example Ozone over Arosa Kunz, H., S. Scherrer, C. Appenzeller and M. Liniger, 2007: The evolution of ERA-40 surface temperatures and total ozone compared to observed Swiss time series, Meteorol. Z., DOI: 10.1127/0941-2948/2007/0183 Differences total ozone ERA-40 & homogenized observations over Arosa

9. 9 Research activities Climate Services & NCCR Christof Appenzeller et al. New long snow series in the Alpes Digitising of new snow sum (and snow depth) series Reconstruction of days with snow pack via snow depth reconstruction (daily temperature/precipitation) Sils Maria 1864 – 2005 (1798 m asl) cm/yr days/yr Sils Maria 1864 – 2005 (1798 m asl) new snow sum days with snow pack (>1cm) Davos 1999 Savognin 1990 Wüthrich C, et al., 2010: in preparation. Scherrer, S. C., C. Appenzeller, and M. Laternser, 2004: Trends in Swiss Alpine snow days: The role of local- and large-scale climate variability, Geophys. Res. Lett., 31, L13215, doi:10.1029/2004GL020255.

10. 10 Research activities Climate Services & NCCR Christof Appenzeller et al. Gridding in complex topography COST733 Weather classification 1929 Stations (AUT, CH, DL) Heavy Precipitation event in the Alps August 2005 Frei, C, and C. Schär, 1998, A precipitation climatology of the Alps from high- resolution rain-gauge observations., Int. J. Climatol., 18, 873-900. Frei, C, et al, 2006: Starkniederschlagsereignis August 2005, Arbeitsbericht MeteoSchweiz Nr. 211, ISSN: 1422-1381 Christop Frei and Reinhard Schieman

11. 11 Research activities Climate Services & NCCR Christof Appenzeller et al. www.meteoswiss.ch  climate  seasonal outlook Monthly/seasonal climate outlooks

12. 12 Research activities Climate Services & NCCR Christof Appenzeller et al. MeteoSwiss research within National Centre for Competence in Research – Climate NCCR I at MetCH: 2001-05 NCCR II at MetCH: 2005-09 See www.meteoswiss.ch  Research  Projects  NCCR-Climate IIwww.meteoswiss.ch

13. Eidgenössisches Departement des Innern EDI Bundesamt für Meteorologie und Klimatologie MeteoSchweiz MeteoSwiss research within National Centre for Competence in Research – Climate Some recent high lights: A. Weigel, M. Liniger, C. Appenzeller

14. 14 Research activities Climate Services & NCCR Christof Appenzeller et al. Skill of today seasonal forecast system (ECMWF Sys 3) 2m temperature SpringSummer AutumnWinter bad good 1 0 RPSSd Can discriminate in 55-60% of the cases

15. 15 Research activities Climate Services & NCCR Christof Appenzeller et al. A perfect ensemble forecasts Consider a climatology of observed outcomes

16. 16 Research activities Climate Services & NCCR Christof Appenzeller et al. A perfect ensemble forecasts Due to a predictable signal (e.g. anomaly in SST), the distribution of possible outcomes is shifted and sharpened

17. 17 Research activities Climate Services & NCCR Christof Appenzeller et al. A perfect ensemble forecasts A reliable forecast samples the distribution of possible states, given the predictable signal

18. 18 Research activities Climate Services & NCCR Christof Appenzeller et al. A realistic ensemble forecasts  Overconfident forecasts are too sharp while being centered at the wrong location (uncertainty ε)

19. 19 Research activities Climate Services & NCCR Christof Appenzeller et al. A realistic ensemble forecasts  Overconfident forecasts are too sharp while being centered at the wrong location (uncertainty ε)

20. 20 Research activities Climate Services & NCCR Christof Appenzeller et al. Statistical post-processing Muotathaler Method 1: multi-model approach (ECMWF, UK MetOffice, Météo France) Muotathaler Weigel, A., M. Liniger and C. Appenzeller, 2008: Can multi-model combination really enhance prediction skill of ensemble forecasts ?, Q. J. R. Meteorol. Soc. 134: 241–260 (2008) DOI: 10.1002/qj.210 Weigel, A., M. Liniger and C. Appenzeller, 2009: Seasonal ensemble forecasts: Are recalibrated single models better than multi- models?, in preparation. Method 2: Climate conserving recalibration (inflation) of single models

21. 21 Research activities Climate Services & NCCR Christof Appenzeller et al. Ensemble forecasts  Overconfident forecasts are too sharp while being centered at the wrong location (uncertainty ε)

22. 22 Research activities Climate Services & NCCR Christof Appenzeller et al. Ensemble forecasts Combining 2 overconfident models

23. 23 Research activities Climate Services & NCCR Christof Appenzeller et al. Ensemble forecasts Combining 3 overconfident models

24. 24 Research activities Climate Services & NCCR Christof Appenzeller et al. Ensemble forecasts Combining “many” overconfident models The effect of multi- model combination is to widen the ensemble spread and to reduce the uncertainty in the ensemble mean

25. 25 Research activities Climate Services & NCCR Christof Appenzeller et al. ECMWF UKMO Multi-models (example JJA forecasts) More improvement possible by weighting…. 1 0 RPSSd

26. 26 Research activities Climate Services & NCCR Christof Appenzeller et al. Recalibration Cheaper and easier to implement than multi-model The recalibration destroys part of the predictable signal 

27. 27 Research activities Climate Services & NCCR Christof Appenzeller et al. raw Average RPSS Recalibration versus multi-models High predictability inflated multi E: ECMWF U: UK Met Office C: Météo France Example: 1 month lead JJA 2m temperature forecasts

28. 28 Research activities Climate Services & NCCR Christof Appenzeller et al. raw Average RPSS Recalibration versus multi-models Low predictability inflated multi E: ECMWF U: UK Met Office C: Météo France

29. 29 Research activities Climate Services & NCCR Christof Appenzeller et al. Day 5-11 Day 12-18Day 19-25 Day 26-32 Monthly forecasts warmer than normal cooler than normal normal VarEPS: 32-day EPS (calculated once per week)

30. 30 Research activities Climate Services & NCCR Christof Appenzeller et al. 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 -0.1 -0.2 Monthly temperature forecast skill Day 5-11 Day 12-18 Results: annual mean RPSS D for week 1, 2, and 3 monthly forecast. Day 19-25 …depends on region, season, lead-time (Weigel et al. 2008a, MWR, accepted)

31. 31 Research activities Climate Services & NCCR Christof Appenzeller et al. Seasonal variability and lead time dependence of skill for Europe (Weigel et al. 2008a, MWR, accepted)

32. 32 Research activities Climate Services & NCCR Christof Appenzeller et al. Eidgenössisches Departement des Innern EDI Bundesamt für Meteorologie und Klimatologie MeteoSchweiz I wish you a nice stay in Zürich