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Precipitation variations over the Iberian peninsula under climate change conditions

Precipitation variations over the Iberian peninsula under climate change conditions. C. Rodríguez Puebla y S. Nieto Dept. de Física General y de la Atmósfera Universidad de Salamanca. Seminario CLIVAR_Es , Madrid 11-13 Febrero 2009. Motivation.

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Precipitation variations over the Iberian peninsula under climate change conditions

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  1. Precipitation variations over the Iberian peninsula under climate change conditions C. Rodríguez Puebla y S. Nieto Dept. de Física General y de la Atmósfera Universidad de Salamanca Seminario CLIVAR_Es , Madrid 11-13 Febrero 2009

  2. Motivation Why precipitation shows a trend to decrease over the Iberian peninsula? Trenberth, et al. 2007: Observations: Surface and Atmospheric Climate Change. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge UniversityPress, Cambridge

  3. IPCC report 2007

  4. Observed precipitation time series (DJFM) Datos de la AEMet Datos grid (CRU-Ensembles)‏ Kendall’Z = -2.2 Kendall’Z = -1.2 Precipitation trend AEMet Precipitation trend Cru_Ensemble)

  5. Links between precipitation (DJFM) and the NAO for observations R= -0.67 ± 0.06 Precipi (mm/mes)‏ Lamb & Peppler 1987, BAMS Hurrel et al. 2003, Geophysical Monograph vol. 134 NAO pattern for DJFM (shaded) Correlation pattern between mean precipitation over the IP and sea level pressure (SLP) R= -0.95 ± 0.002

  6. NAO effects on precipitation (DJFM) EOF1 of precipitation_OBS (shaded) and correlation between NAO and precipitation(contour lines) R= -0.92 ± 0.03 Var=74% R= -0.67 ±0.06

  7. What models tell us about the trend of precipitation ? 7

  8. Data: WCRP CMIP3, PCMDI http://www-pcmdi.llnl.gov/

  9. Experiments

  10. Mean precipitation patterns over the Iberian peninsula 20C3M CRU-ENSEMBLES SRES A1B SRES A2

  11. Precipitation simulations averaged over the Iberian peninsula: 20C3M and SRES A2 Multi-model precipitation averaged over the IP Precipitation trend

  12. Precipitation simulations averaged over the Iberian peninsula: 20C3M and SRES A1B Multi-model precipitation averaged over the IP Precipitation trend

  13. Precipitation simulations averaged over the Iberian peninsula: 20C3M and SRES B1 Multi-model precipitation averaged over the IP

  14. Relative precipitation changes: (SRES– 20C3M)*100/20C3M SRES A2 SRES A1B SRES B1

  15. Mehods to obtain the NAO • EOF (Bretherton, 1992, Wallace 1981) • Selection of stations (Jones, 1997) • SLP averaged over areas (Stephenson 2006, Kuzmina 2005) • Project the SLP of model data onto the NAO pattern from reanalysis data.

  16. Precipitation response to NAO

  17. Precipitation response to NAO for multi-models

  18. Links between precipitation and NAO 20C3M NAO pattern for DJFM (shaded) Correlation pattern between mean precipitation over the IP and sea level pressure (SLP) EOF1 of precipitation_model (shaded) and Correlation between NAO and precipitation (contour lines) R= -0.907 ± 0.004 R= -0.89 ± 0.03

  19. Links between precipitation and NAO SRES A2 NAO pattern for DJFM (shaded) Correlation pattern between mean precipitation over the IP and sea level pressure (SLP) EOF1 of precipitation_model (shaded) and Correlation between NAO and precipitation (contour lines) R= -0.979 ± 0.001 R= -0.84 ± 0.04

  20. Links betweenprecipitation and NAO SRES A1B NAO pattern for DJFM (shaded) Correlation pattern between mean precipitation over the IP and sea level pressure (SLP) EOF1 of precipitation_model (shaded) and Correlation between NAO and precipitation (contour lines) R= -0.979 ± 0.001 R= -0.92 ± 0.02

  21. Links between precipitation and NAO SRES B1 NAO pattern for DJFM (shaded) Correlation pattern between mean precipitation over the IP and sea level pressure (SLP) EOF1 of precipitation_model (shaded) and Correlation between NAO and precipitation (contour lines) R= -0.978 ± 0.001 R= -0.91 ± 0.02

  22. Summary and Conclusions • Observed precipitation over the Iberian peninsula shows: • a trend to decrease in DJFM • opposite correlation with NAO • 21 st century simulations indicate a decrease in precipitation with greater significance for strong CO2 forcing. • The links between precipitation and NAO will become more significant for 21 st century simulations with strong forcing of CO2. • Therefore, the rate to decrease of Iberian precipitation will accelerate under climate change conditions.

  23. Acknowledments To the AEMet and Institute of Meteorology and Geophysics of Portugal for precipitation data. EU-FP6 project ENSEMBLES (http://www.ensembles-eu.org) and ECA&D (http://eac.knmi.nl .) for precipitation data. To the modelling groups for the model data CMIP3 and PCMDI that archives and distributes the data. To the NCEP/NCAR for the reanalysis data and the CPC for SLP and teleconnection indices. This research is supported with National and Regional projects CGL2005-06600-CO3- 01/CLI, CGL2008-04619/CLI and CyL SA123A08. To the software developers GrADS and CDAT

  24. Thank you very much for your attention

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