Transcript Folie 1

Storminess in Northern Italy, the Adriatic Sea
and a comparison to some other EU areas
Christoph Matulla
Central Institute for Meteorology and Geodynamics, Austria
Environment Canada, Toronto, Canada
Hans von Storch
Institute for Coastal Research, GKSS Research Center,
Germany and KlimaCampus Hamburg, Germany
27 October 2008, CORILA meeting in Venice
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1851 foundation of the Austrian weather service,
since 1872 located at Hohe Warte 38, architect:
Johann Heinrich Freiherr von Ferstel
1873 foundation of the International Meteorological Organization
(IMO) in Vienna -- precurser organization of the WMO
Natural disasters 1980 - 2006 Percentage
distribution worldwide
© 2007 NatCatSERVICE, Geo Risks Research, Munich Re
Taken from a presentation given by Mr Berz in Innsbruck at
a COST meeting (2008)
Overall losses:
US$ 1,700bn*
3% wildfire 2% winter damage, frost
7% heat wave, drought
19% earthquake
<1% landslide
1% flash flood
12%
Insured losses:
US$ 400bn*
23% flood
2% wildfire
1 % heat wave, drought 2,5% winter damage, frost
6,25% earthquake
1% flash flood
0,25% tsunami
6% flood
3% hail
5,5%
7% 6,5%
81%
<1% volcanic activity
1% tsunami
24%
44%
29% tropical storm
1% hail
5% severe storm
2% tornado
6% winter storm, blizzard
1% other storms
11% severe storm
4% tornado
1% other storms
20%
49% tropical storm
*original values
13% winter storm,
blizzard
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Storminess in Northern Italy, the Adriatic sea
and a comparison with some other areas
What is happening to extratropical
storminess? Is it presently evolving
outside its range of natural variability?
At first sight this question appears to be best answered by
the help of wind statistics, but wind time series are almost
always
• inhomogeneous
• too short
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One example from Vienna
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Pressure based proxies are one way
to assess storminess (WASA, 1998)
Air pressure readings are usually homogenous and extend
far back in time (pressure measurements are the ‘flagship’
of the meteorological measuring program)
Storm-proxies may be:
Annual/seasonal percentiles of geostrophic wind derived from
triangles of pressure readings (e.g., 95 or 99%iles); such percentiles
of geostrophic wind and of “real” wind are linearly related.
frequency of events with geostrophic wind equal or larger than 25 m/s
frequency of 24 hourly local pressure change of 16 hPa in a year
frequency of pressure readings less than 980 hPa in a year
Hovmöller diagrams
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What it is about
Northern Italy
and the
Adriatic Sea
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Data across southern Europe are
retrieved from http://eca.knmi.nl/
normalized
21 year Gaussian filtered
Southern European data were
downloaded from the European Climate
Assessment & Dataset homepage
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Homöller diagrams of seasonal
pressure readings @ Hvar
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The same for the tendencies @Hvar
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Percentiles of daily pressure
readings taken @ Lugano
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TENDENCIES
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Percentiles of daily pressure observations
@ Gospic
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Gospic‘s tendencies
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What‘s up?
•There is remarkable variablity within the
pressure readings and their tendencies on a
decadal timescale or so.
•The Hovmöller diagrams reveal not much
change in strom proxies over the past century.
•That doesn‘t mean that there is no change
ahead. It simply says that presently we don‘t
experience a change in the storm climate
triggered by climate change.
•Climate change is distinct in thermic
parameters (continental temperatures,
extention of sea ice, sea level, glacier retreat,
etc.) but not conveyed in storminess right now.
•Do we have to fear powerful changes?
Regarding storminess it doesn‘t look like this.
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What‘s out there in other areas? How does
the Italian result match with other regions
in Europe?
99%iles of annual
Relevant publications
geostrophic wind speeds
for a series of station
triangles in the North Sea
regions and in the Baltic
Sea region.
Alexandersson et al., 2002
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Putting geo-wind stories across
Europe together
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What may happen in the future?
RCAO/ECHAM4
A2 Szenario
IPCC 2007
2008-03-13
OEKT-10, Wien
RCAO/HadAM3H
Conclusion
1. Monitoring extra-tropical storminess may be based on air pressure
proxies.
2. This allows assessments for 100 and more years, which is essential.
3. Decades long upward and downwards trends have been detected.
4. These trends are not sustained and have shown recent reversals in all
considered regions.
5. Recent trends are not beyond the range of natural variations, as given
by the historical past, but are more of intermittent character. Regional
temperatures rose significantly at the same time.
6. In N Europe the present absence of a detectable signal is consistent
with RCM simulations.
7. In C Europe a positive trend to average storminess is to be observed
8. The areas we looked on in Europe show no significant change in
storminess there seems to be no significant tend.
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N Europe storminess
Relevant publications
Schmidt, H. and H. von Storch, 1993: German Bight storms analyzed. - Nature 365, 791
Alexandersson, H., T. Schmith, K. Iden and H. Tuomenvirta, 1998: Long-term trend variations of
the storm climate over NW Europe. The Global Atmos. Oc. System 6, 97-120
WASA, 1998: Changing waves and storms in the Northeast Atlantic? - Bull. Amer. Met. Soc. 79,
741-760
Bärring, L. and H. von Storch, 2004: Northern European Storminess since about 1800. Geophys.
Res. Letters 31, L20202, doi:10.1029/2004GL020441, 1-4
Rockel, B., and K. Woth, 2007: Future changes in near surface wind extremes over Europe from an
ensemble of RCM simulations. Climate Change, 10.1007/s10584-006-9227-y
Matulla, C., W. Schöner, H. Alexandersson, H. von Storch, and X.L. Wang, 2007: European
Storminess: Late 19th Century to Present, Climate Dynamics DOI 10.1007/s00382-007-0333-y
The BACC author team, 2008: Assessment of Climate Change in the Baltic Sea Basin, Springer
Verlag Berlin - Heidelberg; ISBN 978-3-540-72785, 473 pp
von Storch, H., and R. Weisse, 2008: Regional storm climate and related marine hazards in the
Northeast Atlantic, In Diaz, H.F. and Murnane, R.J. (eds.), Climate Extremes and Society,
Cambridge: Cambridge University Press (in press)
Matulla, C., and H. von Storch, 2008: Changes in Eastern Canadian Storminess since 1880. under
revision
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Shall we pay more
money to
insurance
companies?
2008-03-13
OEKT-10, Wien