1 / 16

Influence of Blended Ship Log Book on Mediterranean Climate Back to 1750

This study explores the impact of blended ship log book data on Mediterranean temperature and precipitation trends back to 1750. Findings suggest significant correlations and predictive skill in understanding climate variability.

arva
Télécharger la présentation

Influence of Blended Ship Log Book on Mediterranean Climate Back to 1750

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Influence of the blended ship log book and station SLP data set on Mediterranean temperature & precipitation back to 1750June 23 2008 Jürg Luterbacher and collaborators Oeschger Centre for Climate Change Research and Institute of Geography University of Bern, Bern, SwitzerlandEmail: juerg@giub.unibe.ch

  2. Outline • Introduction, why is the Mediterranean of importance? • CCA between the blended SLP data and Mediterranean winter climate 1750-2006 main patterns, trends and crossvalidation • Future scenarios • Conclusions

  3. Network, Winter SLP 1817 after Tambora (April 1815) and Verification statistics L L H Very good quality Küttel et al. 2008

  4. European Winter temperature and SLP anomalies 1817 - + Luterbacher et al. 2007; Fischer et al. 2007; Küttel et al. 2008

  5. + - + Tambora (April 1815), produced the “year without a summer 1816” Luterbacher et al. 2007; Fischer et al. 2007; Küttel et al. 2008

  6. Why is the Mediterranean of importance? • The area is a ‘Hot-Spot’ for which potential climate change impacts on the environment and other activity sectors are particularly pronounced • Local/regional feedbacks (e.g. soil moisture-precipitation feedback), changes in atmospheric circulation and modes of natural variability are of importance • Importance of hydrological cycle, winter precipitation is crucial Water resources & water quality Agriculture & environment Economics & social development & behaviour

  7. Importance of winter precipitation compared tothe annual rainfall (in %) Xoplaki 2002

  8. Data and Methods Independent reconstructions • Gridded temperature 1750-2006, Mediterranean land areas(Luterbacher et al. 2004, 1901-2006 Climatic Research Unit) • Gridded precipitation 1750-2006, Mediterranean land areas(Pauling et al. 2006, 1901-2006 Climatic Research Unit) • Gridded SLP 1750-2006, combined station pressure and CLIWOC/ICOADS data(Allan and Ansell, 2006; Küttel et al. 2008) Method • Canonical Correlation Analysis (CCA) selection of optimally correlated patterns between SLP and Mediterranean temperature & precipitation

  9. CCA1(SLP – temperature/precipitation 1750-2006) dryer and warmer (North), wetter and cooler (South) + warm & dry cool & wet wetter and cooler (North), drier and warmer (South) Xoplaki et al. 2008, work in progress

  10. CCA2(SLP – temperature/precipitation 1750-2006) _ dry and warm, pos NAOI warm & dry + wet and cool, neg NAOI Xoplaki et al. 2008

  11. Mediterranean winter precipitation and temperature trends 1966-2006 Precipitation Temperature Overall drying trend Overall warming trend GISS/NASA

  12. Cross-validation; importance of SLP to explain Winter precipitation and temperature variability1750-2006 Precipitation Temperature Good skill: northern parts and Iberia Good skill: northern and eastern parts Xoplaki et al. 2008

  13. Impacts of recent climate change in the Mediterranean (deforestation, desertification, drought, fires …)

  14. A1B-Scenario for Winter 2021-2050(with respect to 1961-1990) Sea Level Pressure + 2 hPa Temperature Precipitation + 1–2°C - 10–30% Giorgi and Lionello 2008

  15. Conclusions • New dataset allows dynamical studies on the large scale influence on European climate back to AD 1750 • Crossvalidated results indicate good predictive skill in the north and west (precipitation) and north and east (temperature) • Recent dry and warm winter conditions over the entire Mediterranean are not unique in the context of the past 250 years Regional differences • Recent trend towards drier and wamer conditions seems to be exceptional • The combined influence of two atmospheric patterns (NAO, East Atlantic / Western Russia) account significantly for the recent drier and warmer trend • Scenarios indicate a trend towards more high pressure situations (similar patterns found through CCA) drier and warmer winter conditions  Implications on environment, economy and society

  16. Thank you very much for your attention!

More Related