Jürg Luterbacher and collaborators Oeschger Centre for Climate Change Research and
description
Transcript of Jürg Luterbacher and collaborators Oeschger Centre for Climate Change Research and
Influence of the blended ship log book and
station SLP data set on Mediterranean
temperature & precipitation back to 1750
June 23 2008
Jürg Luterbacher and collaboratorsOeschger Centre for Climate Change Research andInstitute of GeographyUniversity of Bern, Bern, SwitzerlandEmail: [email protected]
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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
Outline
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Küttel et al. 2008
Network, Winter SLP 1817 after Tambora (April 1815) and Verification statistics
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Very good quality
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European Winter temperature and SLP anomalies 1817
Luterbacher et al. 2007; Fischer et al. 2007; Küttel et al. 2008
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Tambora (April 1815), produced the “year without a summer 1816”
Luterbacher et al. 2007; Fischer et al. 2007; Küttel et al. 2008
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> 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
Why is the Mediterranean of importance?
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Importance of winter precipitation compared tothe annual rainfall (in %)
Xoplaki 2002
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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
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CCA1(SLP – temperature/precipitation 1750-2006)
dryer and warmer (North),wetter and cooler (South)
wetter and cooler (North),drier and warmer (South)
+warm
& dry
cool
& w
et
Xoplaki et al. 2008, work in progress
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CCA2(SLP – temperature/precipitation 1750-2006)
dry and warm, pos NAOI
wet and cool, neg NAOI
warm & dry
Xoplaki et al. 2008
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Mediterranean winter precipitation and temperature trends 1966-2006
GISS/NASA
Precipitation Temperature
Overall drying trend Overall warming trend
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Cross-validation; importance of SLP to explain Winter precipitation and temperature variability1750-2006
Xoplaki et al. 2008
Precipitation Temperature
Good skill: northern parts and Iberia Good skill: northern and eastern parts
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Impacts of recent climate change in the Mediterranean (deforestation, desertification, drought, fires …)
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A1B-Scenario for Winter 2021-2050(with respect to 1961-1990)
Giorgi and Lionello 2008
Sea Level Pressure
Temperature Precipitation
+ 2 hPa
+ 1–2°C - 10–30%
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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
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Thank you very much forThank you very much foryour attention!your attention!