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Aspects of climate extremes in Finland Ari Venäläinen, Kirsti Jylhä, Andrea Vajda, Tiina Kilpeläinen, Seppo Saku…. CLIMATE RISKS IN FINLAND storms low pressures, tornadoes, down bursts snow slipperiness icing fox turbulence floods an drought hot and cold spells lightning.
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Aspects of climate extremes in FinlandAri Venäläinen, Kirsti Jylhä, Andrea Vajda, Tiina Kilpeläinen, Seppo Saku…
CLIMATE RISKS IN FINLAND • storms • low pressures, tornadoes, down bursts • snow • slipperiness • icing • fox • turbulence • floods an drought • hot and cold spells • lightning
Number of deep low pressures and rapid change of air pressure in Kajaani
980 hPa cases Above 20 hPa change 250 Above 9 hP gradient 200 150 Deviation from mean (%) 100 50 0 1959 1963 1967 1971 1975 1979 1983 1987 1991 1995 1999 2003 Year Helsinki, Jokioinen, Sodankylä storms
TORNADOES Kontiolahti 20.8.2004
Tornadoes in different fujita classes F2+ 1796-1996: 45 % 1997-2003: 8 %
Helsinki 200 150 Preciptation (mm/day) 100 50 0 10 100 1000 Return period (years) Daily precipitation 20 50 500 500 50 20
Summer rain events in Helsinki in 1951-2000: duration and precipitation amount Return period of the duration (hour) of a rain event Return period of precipitationamount (mm) in a rain event Ref: Tiina Kilpeläinen
1, 2, 3, 6 and 12 month precipitation amounts in Finland Monthly Three months Two months Six months Twelve months
1- month 2- months 3- months 6- months 12- months
15 45 wind temp accum. prec 10 40 5 35 0 30 -5 25 -10 (kg/m2) Wind speed (m/s) temeperature (°C) Precipitation (mm) accumulated snow -15 20 -20 15 -25 10 -30 5 -35 -40 0 1.1. 1.2. 1.3. 1.10. 1.11. 1.12. Date Kuusamo 1993-1994
ACCLIM • part of Finnish adaptation research • ”Climate extremes and estimated climate change based on the latest climate scenarios” • In the first part of the study return periods of several parameters are calculated
And the future? December 2006 mean temperature in Helsinki was +4.0 ºC and March 2007 temperature +3.1ºC. The return periods of this high temperatures is more than 500 years This two months demonstrate the difficulty to estimate the reliably the return periods in rapidly changing climate. How to explain all this to media and general public?