Assessing Impacts of Climate Variations and Change on Different Time Scales

Ilmaston muutoksella tarkoitetaan ilmaston keskimääräisen tilan muutosta pitkän ajan, yleensä 30 vuoden tai sitä pidemmän ajanjakson aikana. Ilmaston luonnollinen vuosien välinen vaihtelu taas kuvaa lyhemmässä aikaskaalassa ilmastojärjestelmän sisäistä vaihtelua. Tässä väitöskirjassa on tutkittu viime jääkauden lopun luonnollisen ilmaston muutoksen vaikutusta ihmisten määrään Euroopassa, ihmisten aiheuttaman ilmastonmuutoksen vaikutusta metsäpalovaaran ja voimakkaisiin tuuliin Euroopassa sekä stratosfäärien tuulien ja Arktisen värähtelyn tilastollista yhteyttä nykyilmastossa. Tässä väitöskirjassa karkean erottelukyvyn jääkausi-ilmastosimulaatio alueellistettiin regressiomallilla, joka hyödynsi hilamuotoista aineistoa sekä nykyilmastosta että yleisen kiertoliikkeen mallin jääkausisimulaatioista. Mallinnettujen väestömäärien vaihtelut korreloivat merkitsevästi riippumattoman arkeologisen aineiston väestömäärän muutosten arvioiden kanssa. Ilmastollisten metsäpaloherkkyyteen vaikuttavien suureiden viimeaikaista trendiä Euroopan alueella tutkittiin ERA-Interim- ja ERA-40-uusanalyysiaineistojen avulla. Metsäpaloriskin havaittiin kasvaneen Etelä- ja Itä-Euroopassa jaksolla 1980–2012, kun taas muualla Euroopassa selvää trendiä ei ollut havaittavissa. Ihmisten aiheuttaman ilmaston muutoksen vaikutusta tuulisuuteen Pohjois-Euroopassa kuluvan vuosisadan aikana tutkittiin yhdeksällä yleisen kiertoliikkeen mallilla. Tulosten perusteella keskimääräisten ja voimakkaimpien geostrofisten tuulien muutokset ovat muutaman prosentin luokkaa; mallinnukset kuluvalle vuosisadalle näyttivät näiden tuulien voimistuvan joitakin prosentteja osassa Luoteis-Venäjää ja Itämeren eteläosia ja heikkenevän muutamia prosentteja Norjanmerellä. Tässä väitöskirjassa tutkittiin stratosfäärin tuulien ja arktisen värähtelyn yhteyttä tilastollisesti. Hyödyntämällä stratosfääristä saatavaa signaalia pystyttiin 3-6 viikon päähän ulottuvia säämalleilla tehtyjä Pohjois-Euroopan viikkokeskilämpötilojen ennusteita hieman parantamaan.Climate change refers to a change in the mean state of the climate that persists for an extended period, typically 30 years or longer. The natural inter-annual variability of climate refers to internal variation of the climate system in shorter time-scales. In this thesis I have studied the climate of the last glacial and its impact on human population sizes in Europe during the end of the last glaciation, the change in forest fire danger and strong winds in Europe under the on-going human-induced climate change, and the relationship between the stratospheric winds and the phase of the Arctic Oscillation in present climate. A regression model was developed to downscale low-resolution dynamical EMIC simulations to regional scale. The regression model was calibrated by gridded data of regional scale resolution observations of present day climate and simulations of glacial climate. The downscaled climate was used in estimating the size of human population in Europe during the end of the last glaciation, between 30,000 and 13,000 years ago. The simulated changes in human population size correlated significantly with an independent archeological data of changes in human population size. The change in the forest fire danger in Europe was investigated by ERA-Interim and ERA-40 reanalysis. The forest fire danger was found to have increased in Southern and Eastern Europe during the period 1980–2012, whilst no significant trend was found elsewhere in Europe. The projected changes in the geostrophic wind speeds under human-induced climate change in Northern Europe during the current century were explored from simulations of nine general circulation models. According to the simulations, the changes in mean and extreme wind speeds are going to be small; in parts of northwestern Russia and southern Baltic Sea the winds might increase by 2-4% and over the Norwegian Sea the winds might decrease by 2-8%. In this thesis the connection between the stratospheric winds and surface Arctic Oscillation was studied statistically. The found stratospheric connection was applied in post-processing the European Centre for Medium-Range Weather Forecasts two-week mean temperature reforecasts for weeks 3–4 and weeks 5–6 in Northern Europe during boreal winter, and the skill scores of those weeks were slightly improved

Statistical downscaling of a climate simulation of the last glacial cycle : Temperature and precipitation over Europe

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The association between physical activity during preschool hours and early numeracy

Previous findings suggest positive association between physical activity (PA) and children's cognitive outcomes. Early numeracy (EN) refers to young children’s mathematical proficiency, including relational and counting skills. EN has been shown to strongly predict later mathematical and academic achievements. Previous research has mainly focused on school-age children; however, research in early ages is scarce. No previous studies have used device-based measurement of PA with an individual test of EN to understand the associations between preschool PA and EN. The study investigated the relationship between PA during preschool hours and EN in 4-5-year-old children (N = 95, Mage = 4.6). PA was measured during 5 consecutive preschool days using hip-worn accelerometers, while EN was assessed using the Finnish Early Numeracy Test. Results revealed no significant correlation between preschool PA level and EN. Furthermore, latent profile analyses identified three profiles with high, medium, and low PA, whereas EN did not significantly differ among the profiles. While the results showed significantly different amounts of PA among children during preschool, the current study suggests no direct relation between preschool PA and EN

The risk of overheating and energy demand of new and old Finnish apartment buildings in the cooling season

This study has compared the risk of overheating of a new and old apartment building in Finland and aimed to improve the indoor temperature conditions of the new apartment building using the passive strategies (sun shading, window opening, and window properties) and an active cooling system. So that seven different cases were defined and simulated. Regarding the results, the risk of overheating in the old building is significantly less than in the new building, and using new well-insulated windows with the same old wall construction in the old building, decreases the heating demand but has no significant effect on indoor air temperature. So that the windows are more important for energy usage but not for the indoor air temperature in the old Finnish apartment building during the summer period. Using openable windows would be the best passive solution for keeping the indoor air temperature of the spaces of the new building within the comfort limits with less than 10% of the time above the recommended temperature limits based on EN 16789-1 standard without any significant increase in heating demand. While Using an active cooling system in the living room of each apartment is the only solution that can provide thermal comfort for 100% of the cooling season in all the spaces including bedrooms.publishedVersio

Adding value to Extended-range Forecasts in Northern Europe by Statistical Post-processing Using Stratospheric Observations

The strength of the stratospheric polar vortex influences the surface weather in the Northern Hemisphere in winter; a weaker (stronger) than average stratospheric polar vortex is connected to negative (positive) Arctic Oscillation (AO) and colder (warmer) than average surface temperatures in northern Europe within weeks or months. This holds the potential for forecasting in that timescale. We investigate here if the strength of the stratospheric polar vortex at the start of the forecast could be used to improve the extended-range temperature forecasts of the European Centre for Medium-Range Weather Forecasts (ECMWF) and to find periods with higher prediction skill scores. For this, we developed a stratospheric wind indicator (SWI) based on the strength of the stratospheric polar vortex and the phase of the AO during the following weeks. We demonstrate that there was a statistically significant difference in the observed surface temperature in northern Europe within the 3-6 weeks, depending on the SWI at the start of the forecast. When our new SWI was applied in post-processing the ECMWF's 2-week mean temperature reforecasts for weeks 3-4 and 5-6 in northern Europe during boreal winter, the skill scores of those weeks were slightly improved. This indicates there is some room for improving the extended-range forecasts, if the stratosphere-troposphere links were better captured in the modelling. In addition to this, we found that during the boreal winter, in cases where the polar vortex was weak at the start of the forecast, the mean skill scores of the 3-6 weeks' surface temperature forecasts were higher than average.Peer reviewe

Evolution of the ring current energy during May 2-4, 1998 magnetic storm

We study the evolution of the ring current energy density during May 2-4, 1998 storm event as measured by Polar CAMMICE/MICS instrument and modelled by proton tracing in the guiding center approximation. Particle data from Polar shows that during the storm main phase protons with medium energies (20-80 keV) contribute more to the total ring current energy than the high energy protons (80-200 keV) whereas during the recovery phase high energies dominate. We trace protons with arbitrary pitch angles numerically in the guiding center approximation taking into account charge-exchange losses. Tracing is performed in the large-scale and smaller-scale time-dependent magnetic and electric field models. We model the substorm activity by several electric field pulses at times of the substorm onsets. It is shown that impulsive electric fields associated with substorms are effective in the proton transport and energization to higher energies more than 100 keV in the storm time ring current

How performance measurement can support achieving success in project-based operations

This paper investigates the existing and missing connections between the concepts of project management success and organizational success. We build a theoretical framework of the concepts and elaborate on it by examining three innovation project cases—a smart-city project with little organizational success-driven performance measurement, a product development project with overly ambitious project management goals but an overall positive organizational impact, and an R&D project involving practically no project management performance measurement since organizational success was considered paramount. Our unit of analysis in these cases is performance measurement in terms of its alignment or misalignment of success. We contribute to the literature by (1) examining the linkage between organizational success and project performance criteria, (2) exhibiting the interrelations, dominance, and use of certain project performance measures in determining whether a project is successful, and (3) offering a framework for understanding how performance measurement can support success in project-based operations.publishedVersionPeer reviewe

The usefulness of Extended-Range Probabilistic Forecasts for Heat wave forecasts in Europe

Severe heat waves lasting for weeks and expanding over hundreds of kilometres in horizontal scale have many harmful impacts on health, ecosystems, societies, and economy. Under the ongoing climate change heat waves are becoming even longer and hotter, and as proactive adaptation, the development of early warning services is essential. Weather forecasts in extended range (2 weeks to 1 month) tend to indicate a higher skill in predicting warm extremes than average temperature events in Europe. We verified hindcasts of the European Centre for Medium-Range Weather Forecasts (ECMWF) in forecasting heat wave days, i.e., periods with the 5-day mean temperature being above its 90th percentile. The verification was done in 5° × 2° resolution over Europe, based on the forecast week (1 to 4 weeks). In the first forecast week, it is evident that across Europe, the accuracy of ECMWF heat wave forecasts surpasses that of a mere climatological forecast. Even into the second week, in many places in Europe, the ECMWF forecasts prove to be more reliable than their statistical counterparts. However, if we extend the forecast lead time to 3–4 weeks, predictability begins to lower to such a level that it can no longer be said, with the exception of Southeastern Europe, that the forecasts in general were statistically significantly better than the statistical forecast. Nonetheless, intense and prolonged heat waves during the third forecast weeks appear to have a higher-than-average level of predictability

Exploring the Role of Weather and Forest Management on Nutrient Export in Boreal Forested Catchments Using Spatially Distributed Model

Weather-driven hydrological variability and forest management influence the nutrient export from terrestrial to aquatic systems. We quantified the effect and range of variation in total nitrogen and phosphorus export in Vehka-Kuonanjärvi catchment located in southeastern Finland. A distributed model NutSpaFHy was used with varying weather scenarios (compiled from observed extreme years of dry, wet and wet & mild) and forest management scenarios (including no additional management and intensive clear-cutting of all mature stands in the existing forest structure). Nutrient exports by scenario combinations were compared to modeled baseline export in observed weather. The results showed that the increase in nutrient export by wet & mild weather (over 55%) exceeded the increase caused by the clear-cutting scenario (23 %). Dry weather decreased the exports to tenth of the baseline, which was per hectare 2.22 kg for N, 0.08 kg for P). The results suggest that in future maintaining a good ecological status in aquatic systems can be challenging if extreme wet years with mild winters occur more frequently. Certain catchment characteristics, e.g., deciduous tree percentage, open area percentage and site fertility, influence the export increase induced by the extreme weather. Hotspot analysis enabled identifying areas with currently high nutrient export and areas with high increase induced by the extreme weather. This helps targeting water protection efficiently

Human population dynamics in Europe over the Last Glacial Maximum

The severe cooling and the expansion of the ice sheets during the Last Glacial Maximum (LGM), 27,000-19,000 y ago (27-19 ky ago) had a major impact on plant and animal populations, including humans. Changes in human population size and range have affected our genetic evolution, and recent modeling efforts have reaffirmed the importance of population dynamics in cultural and linguistic evolution, as well. However, in the absence of historical records, estimating past population levels has remained difficult. Here we show that it is possible to model spatially explicit human population dynamics from the pre-LGM at 30 ky ago through the LGM to the Late Glacial in Europe by using climate envelope modeling tools and modern ethnographic datasets to construct a population calibration model. The simulated range and size of the human population correspond significantly with spatiotemporal patterns in the archaeological data, suggesting that climate was a major driver of population dynamics 30-13 ky ago. The simulated population size declined from about 330,000 people at 30 ky ago to a minimum of 130,000 people at 23 ky ago. The Late Glacial population growth was fastest during Greenland interstadial 1, and by 13 ky ago, therewere almost 410,000 people in Europe. Even during the coldest part of the LGM, the climatically suitable area for human habitation remained unfragmented and covered 36% of Europe.Peer reviewe