Extreme weather and nuclear power plants (EXWE) Midterm seminar

Transcription

1 Extreme weather and nuclear power plants (EXWE) Midterm seminar Climatological and meteorological research: Hilppa Gregow, Pauli Jokinen, Matti Lahtinen, Ari Venäläinen, Kirsti Jylhä, Kimmo Ruosteenoja, Pentti Pirinen, Markus Peura, Seppo Saku, Juha Aalto, Jenni Rauhala Marine research: Milla Johansson, Hilkka Pellikka, Kimmo Kahma, Hanna Boman, Katri Leinonen, Anu Karjalainen Ilmatieteenlaitos/PowerPoint-ohjeistus/N.N

2 Aim of the Project: A comprehensive study about the frequency, intensity, spatial and temporal variation and the impacts of the extreme weather and sea level events that are relevant from the point of safety of nuclear power plants in Finland taking into account the influence of climate change on the extreme events. Ilmatieteenlaitos/PowerPoint-ohjeistus/N.N

3 OUTLINE Millenium simulations Weather extremes and variation: Heat and cold Storms Lake-snow-effect Freezing rain PYHÄJOKI Baltic Sea extremes and variation Meteotsunamis Sea level rise global regional OLKILUOTO LOVIISA Ilmatieteenlaitos

4 MILLENIUM GRID Single Parameters and weather patterns A combination of relevant weather parameters and weather patterns Ilmatieteenlaitos/PowerPoint-ohjeistus/N.N

5 Hot temperatures Typical weather patterns for extreme heat (200-yr return period) Three days before At the time of extreme occurrence Ilmatieteen laitos

6 Return level studies: example Loviisa For example the best estimates of the 1000 year return level extreme temperatures in Loviisa are C and -38 C Based on observations only, C and C, respectively RESULT: Uncertainty in the estimates decreased Ilmatieteen laitos

7 Duration studies: example Olkiluoto Extremely warm cases occurring once in 200 years (meaning average estimate 33,3 C) Maximum durations (hours) Year Ilmatieteen laitos

8 Cold spells Typical weather patterns for extreme cold (200-yr return period) Three days before At the time of extreme occurrence Ilmatieteen laitos

9 Monthly distribution: example Pyhäjoki Cases occurring once in 200 years Number of cases Cold spells Heat waves Month Ilmatieteen laitos

10 LAST TWO CENTURIES BASED ON THE MILLENIUM SIMULATIONS APPEAR TO BE WINDIER THAN BEFORE Ilmatieteen laitos

11 Time series of the annual maximum geostrophic wind speeds based on five simulations in Finland PYHÄJOKI LOVIISA OLKILUOTO L 955 Pressure gradient effect Geostrophic wind Coriolis effect True wind Friction effect Isobar Ilmatieteenlaitos

12 Extreme storms Examples of extreme storm weather patterns (200-yr return period) October November Ilmatieteen laitos

13 In five simulations (alltogether 6000 years) ALL THESE STORM RELATED RESULTS MEAN THAT: 12 risk for stronger storms than have been observed in Finland is real and existing this supports earlier findings on return periods of strong winds Millenium based results are also in line with the climate projections that say strong wind speeds are projected to increase in northern Europe Number of cases occurring once in 200 years Month Loviisa Olkiluoto Pyhäjoki Ilmatieteen laitos

14 Estimated gust wind speeds of 51 strong storms in Europe in Estimated maximum gust wind speed (ms-1) durign the storm ERA-40 ERA-Interim Year Higher resolution gives stronger winds (in this case the difference is %) Ilmatieteenlaitos

15 Lake-effect-snow Needs an open water surface as source of humidity and energy Needs very large temperature gradients Cold air ( ºC) moving at certain speed from the cold continent over the warmer water surface We tested the model with cases known from Sweden and then applied this method to Finland Kuva 1. Tutkakuva lumikanuunatilanteesta etelärannikolla 21. joulukuuta Ilmatieteenlaitos

16 Lake-effect snow main results Typical weather pattern during a severe case in Olkiluoto Three days before At the time of extreme occurrence Ilmatieteenlaitos

17 Snow load example: Loviisa Snow load estimate Snow load (kg/m 2 ) Year Ilmatieteenlaitos

18 Risk for sudden large snow amount due to lake-effect Number of cases (every 6 hour case is inlcluded) Month Ilmatieteenlaitos

19 Freezing rain The vertical temperature profile, large scale weather pattern distribution only indicate the possibility of a freezing rain episode - for a model with coarse resolution this is a challenge We developed the best possible detection method when only Millenium-data was availabe and calculated the ice loads and compared these to the ones reported in Sweden, Russia and Canada Freezing rain in Russia Unusually warm air moved over Russia from south At surface temperatures were below zero by >10 degrees Ilmatieteenlaitos

20 MOST SEVERE MILLENIUM FREEZING RAIN CASE IN FINLAND Three days before October 22 nd 1973 NOTE: this weather pattern is a little bit like the case in Russia BUT here very relevant is the temperature difference between the surface and the 850hPa level - it needs to be larger Ilmatieteenlaitos

21 Freezing rain main results Very little observations from Finland, Sweden but many from Canada The 8 cases (4-7 mm) from Finland were found ( ) based on archives but also interviews Typical more influencal situation covers Sweden, Finland, Baltic countries and parts of Russia SMHI helped in finding the 23rd October 1921 case in this particular case sleet and temperature variations played an important role not the freezing rain Class Freezing rain Effect KNOWN Theoretically possible mm small mm moderate mm severe mm very severe 5 > 60 mm catastrophy Ilmatieteenlaitos

22 Meteotsunamis work on-going Meteotsunamis: long tsunami-like waves caused by mesoscale atmospheric pressure disturbances and resonance effects Three meteotsunami cases were reported by eyewitnesses on the Finnish coast in 2010 and 2011: rapid sea level fluctuations of up to 1 m and strong currents with varying direction (Pellikka et al. 2013) Squall line over water New statistical methods for detecting the meteotsunamis from the archives are being developed Ilmatieteenlaitos

23 Meteotsunamis main results Observed meteotsunami events were caused by squall lines or gust fronts moving above the sea at a resonant speed Propagation speed resolved from radar data Strongest known meteotsunamis in Sweden and Finland m Historical evidence of stronger possible meteotsunamis from the Polish coast Preliminary result: meteotsunamis have become more common on the Finnish coast reason unknown (research continues) European Conference on Severe Storms, Helsinki Baltic Sea Science Congress, Klaipeda Squall line propagation over the Gulf of Finland Ilmatieteenlaitos

24 Regional sea level rise Global sea level rise: cm in (combining recently published scenarios) Adjusted to take in account regional effects: Regional fingerprints of glacier and ice sheet contributions (changes in Earth s gravity field) Land uplift Wind conditions => Gulf of Finland cm Bothnian Sea cm Bothnian Bay cm (Johansson et al. 2012, in press) Greenland ice sheet fingerprint (Mitrovica et al. 2001) Ilmatieteenlaitos

25 Curved sea level scenarios were constructed following the intrepolation methods applied e.g. in Johansson et al. (2013) The results show considerably less deviation from high scenarios but the observations still follow the first quartile of the scenarios. Ilmatieteenlaitos/PowerPoint-ohjeistus/N.N

26 SUMMARY 1/2 COLD SPELLS AND HEAT WAVES We obtained new return levels especially for the longer return periods and minimized the uncertainty in the calculations STORMS Based on the millenium results and climate change projections being prepared for worse storms than we have experienced is necessary LAKE EFFECT SNOW The theoretically possible extreme lake effect snow could in Finland cause around 100 kg/m 2 snow loads in 1-3 days FREEZING RAIN The theoretically possible extreme freezing rain in Finland may reach 20 mm during a freezing rain episode Ilmatieteenlaitos/PowerPoint-ohjeistus/N.N

27 SUMMARY 2/2 METEOSTUNAMIS The strongest known meteotsunamis on the Finnish and Swedish coasts are about meters high and these oscillations are included in distributions of sea level extremes It appears that the frequency of rapid sea level oscillations has increased during the past decades SEA LEVEL MAXIMA AND SCENARIOS The annual sea level maxima on the Finnish coast have increased by cm from the 1930s The average changes in wind conditions will result in 6 7 cm higher sea levels by 2100 compared to the current climate - the full scenario range extending from a 4 cm decline to a 19 cm increase The sea level rise observations still follow the first quartile of the scenarios THANK YOU FOR LISTENING Ilmatieteenlaitos/PowerPoint-ohjeistus/N.N