Valerio Lucarini University of Camerino & CINFAI soon University of Bologna

1. Does the Danube exist?Versions of reality given byvarious climate models and climatological datasets Valerio Lucarini University of Camerino & CINFAI soon University of Bologna

2. Intro • Territorial planning and management require the development of deep knowledge concerning some key hydro meteorological and hydrological processes: • Water is central to human and environmental welfare; • About 70% of all natural disasters in the world are caused by hydro-meteorological events • HYDROCARE (INTERREG IIIB – CADSES): Time: 2006-2007, Budget: 2.5 M€; Partnership 11 institutions from 6 countries (Italy, Germany, Greece, Poland, Romania, and Slovakia). Lead Partner, CINFAI, Italy • Mission: Analysis of the hydrological cycle of the CADSES area by adopting an integrated and multidisciplinary approach. • Web-site: http://www.hydrocare-cadses.net • The assessment of the reliability of the current RCMs for the climatology of the water balance (mean value & variability), of the basin of the Danube river is crucial, because of its relevance at social, economical and environmental level. This the reason for its centrality in the project HYDROCARE.

3. Two words on the project:Hydrological cycle of the CADSES regionsHYDROCARE Project part-financed by the EU

4. Basic Information Programme: INTERREG IIIB – CADSES – 3rd call Priority/Measure 4 - Environment protection, resource management and risk prevention4.3 - Promoting integrated water management and prevention of floods Start/End date: 01/01/2006-31/12/2007 Total Budget: 2.466.200,00 € (ERDF Cofinancing: 1.441.625,00 €) Lead Partner National Consortium of Universities for the Physics of Atmospheres and Hydrospheres – CINFAI (IT) Partnership 11 Project Partners from 6 countries (IT, GR, DE, SK, PL, RO)

5. Project Partners • National Consortium of Universities for the Physics of the Atmospheres and of the Hydrospheres (IT) • National Agency for the Environmental Protection and Technical Services - Department of Internal and Marine Waters Protection (IT) • Marche Region - Public Works Design Service (IT) • University of Camerino - Department of Earth Sciences (IT) • Autonomous Province of Trento - Service for Hydraulic Works (IT) • National Technical University of Athens - Department of Water Resources, School of Civil Engineering (GR) • Municipality of Kefalonia (GR) • Potsdam Institute for Climate Impact Research (DE) • Slovak Hydrometeorological Institute (SK) • Institute of Meteorology and Water Management - Branch of Wroclaw (PL) • National Institute of Hydrology and Water Management (RO) • 11 PPs, 6 countries • Local Authorities • Technical Services • Scientific Institutions

6. Objectives • Development of an integrated view of the water resource management, bridging the evaluation of the water resources of the CADSES area with the study of the large and basin-scale hydrological cycle. • Development of effective, internationally shared tools for public and private institutions for the correct management of the water resources as well as for planning future development of the CADSES area. • Development of set of standards at European level for the collection, evaluation, storage and interpretation of the hydro-meteorological data, with particular regard to extreme events of great potential impact on the welfare of the population and on the state of the environment.

7. Work Packages 3 kinds of activities • In-depth activities • In-extension activities • Outreach activities

8. Reconstruction of the Hydrological cycle • NCEP and ERA 40 reanalyses • IPCC 4AR global climate models simulations • Regional Climate Models simulations (e.g. PIK) • Observations (local and remote) • Mostly PP1, PP2, PP5, PP6, PP8 will be involved

9. Hydrological data on basins and sub-basins Main river basins in Poland (PP10) Danubian sub-basin in Slovakia (PP9) Watersheds in Kefalonia (PP6,7) Bratislavadistrict(2053 km2)

10. Erosion and Badlands (PP4) • Seawater-freshwater interaction near estuaries (PP3)

11. Back to the Danube. Basics Courtesy of CIA • Data sources: • ERA-40 reanalysis data • NCEP/NCAR reanalysis data • Regional Climate Models Control data – Prudence project • Global Runoff Data Center – GRDC • Met Office, Hadley Center, UK (driving data) • Daily values of: • Precipitation (P) • Evaporation (E) • Runoff (R) • Observed discharge data (GRDC) • Area of interest: • Danube: length river 2850 Km, Area basin 807 000 km2 • Period of 30 years: 01.01.1961 – 31.12.1990 • Calculation of integral values (over the area, using GIS tools) of: P, E, R, Precipitation – Evaporation (hydrological balance), (P - E) Mass conservation:

12. Regional CM (PRUDENCE 5 FP)

13. Other data (Verification)

14. Data Gridding Voronoi Polygon

15. Statistics of the Yearly time series • Balance (Precipitation – Evaporation) • Precipitation • Evaporation • Runoff

16. Mean vs. Variability High Med μ NCEP Low ERA-40 σ

17. P vs. E μ(E) NCEP Med ERA-40 High Low μ(P)

18. Correlation with Driving AGCM (1)

19. P-E Feedback

20. Correlation with Driving AGCM (2)

21. Runoff vs Balance High μ(B) Not good! Med Low NCEP ERA-40 μ(R)

22. Seasonal Cycle • Balance (Precipitation – Evaporation) • Precipitation • Evaporation • Runoff

23. 100% Max Min Max Min PRECIPITATION

24. Negative balance Max 100% Min Min EVAPORATION

25. Negative balance 100% Max Min BALANCE

26. Phase Amplitude Max Min RUNOFF

27. Geographical limits to water transport? • The Mediterranean Sea play a relevant role in the hydrology of the Danubian region both for the mean state and the extreme events. • The largest impact in terms of precipitation of the Mediterranean water vapor is in the regions downwind of the Sea, thus including Central-Eastern Europe. • The Danube depends almost entirely on precipitated water of Mediterranean origin. Similarly, a very strong Mediterranean influence exists for Elbe, Oder, and Vistula, since they or their main tributaries originate from mountains (Carpatians, Sudety, Erzebirge) which catalyze the precipitation of Mediterranean water

28. Most of the major floodings occurred in central-eastern Europe are due to a typical Mediterranean meteorological pattern, the Genoa cyclone.

29. Conclusions • NCEP and ECMWF Reanalyses are largely inadequate for representing the hydrology of the Danube basin; • RCMs feature large discrepancies for the climatology of water balance: most underestimate the discharge of the Danube; they act as differently parameterized downscaling of the driving GCM; • Only few models (METNO, SHMI, KNMI) provide estimates which are consistent with the observed discharge values of the Danube at its Delta; • Most RCMs have a large and anticipated mean seasonal cycle (small damping); problems in representation of snow depletion: KNMI model agrees remarkably well with observed data; • The agreement between mean integrated P-E and runoff is not perfect; • The considered approach relies on the mass conservation principle at the air-land interface and bypasses the details of soil modelling and will be used for analyzing climate change scenarios. • Analysis of meteorological processes and of transport of water vapor of Mediterrabean origin is crucial • Meteorological Hydrological Cycle, not Geographical Hydrological Cycle

30. Sligthly tragically .. • While the RCMs actually act as strongly constrained downscaling models, at the same time, once outputs are upscaled via spatial integration procedure on a finite - not too large, not too small domain, as discussed earlier - domain, information may be, and actually in most cases is, degraded.