Search

Anthropogenic climate change affects road weather conditions in the northern high latitudes. The expected warmer and wetter future climate implies new challenges for the road transportation sector. Therefore, it isessential to estimate the impacts of climate change on road weather in the Nordic countries. For this purpose, we have set up a road weather model RoadSurf that utilizes meteorological data from a high-resolution regional climate model HARMONIE-Climate. As a first step, we investigated the skill of the road weather model to reproduce present-day road weather conditions in Finland. Simulated road surface temperatures were compared to observations between 2002 and 2014 at 25 road weather stations. RoadSurf accurately captured the characteristics of observed road weather implying this approach can be used to construct the present-day road weather climatologies as well as to study the impacts of climate change on road weather conditions in the studyarea.

Mineral grains in soil are surrounded by pores, the porosity of sandy soil being typically 25-35 % of its volume. Above the water table, such pores are filled with air. The heat stored in the mineral grains is transferred to the surrounding air in the pores. Field experiments on energy storage in unsaturated soil using pore air flow were carried out during 1990 - 1991 in Southern Finland. High volumes of pore air, for example 3 900 m3/h in this study, can be produced from a well installed to a depth of 5-7 m, where natural temperatures remain at 5-6°C throughout the year in Finland. The influence of the pumping can be detected far from the surroundings of the well; a 20 Pa pressure difference was measured in the soil 50 meters from the well in this study. For numerical simulation the multiphase, multicomponent model TOUGH was used, simulating the coupled transport of water, air and heat in gas and liquid phases. Heat transfer due to convection within air was found to be considerable in comparison to conduction. The injection flow rate mainly affects the radius of influence and the temperature of the injection air the temperature distribution near the well. Comparison of the results with a hypothetical situation where air is extracted from the soil under natural conditions shows that the benefit due to air injection reduces in 3 months to about 1 °C. Further studies are needed to take into account the subzero temperatures during the winter period. The possibility of using the model THETA to simulate the flow of air in a porous medium was also studied. The model is microcomputer based and simulates the coupled flow of fluid, heat and solute in saturated porous media. The simulations show that the compatibility of those two models seems to be fairly good. The actual suitability of microcomputer simulations by THETA depends on degree accuracy desired. A markedly better fit with experimental data was observed when more accurate ambient temperature data were used in THETA simulations. Most of the energy flux into the soil was caused by solar energy conduction. From the technical point of view heat can be stored in summer and cold in winter by pumping ambient air into the soil through a well. From the economical point of view this is however not viable. Heat derived from industry could be used with better efficiency. Natural heat storage in the unsaturated zone maintains the produced pore air at temperatures of at least 3-5 °C throughout the winter. From the technical point of view the method can be applied to keep lawns and sports grounds free of snow and unfrozen when occasional snow cover is acceptable. Sufficient data concerning the availability and temperature of pore air for calculations of the use of pore air flow directly into houses as indoor air, to heat greenhouses or to cool air-raid shelters were obtained in the study.

Wintertime slip injuries are a very common problem in Finland as well as in other countries where winter conditions are frequent. According to surveys, on average every third person in Finland slips each winter and more than 50,000 persons are injured needing medical attention. Slipping causes human suffering as well as significant financial costs due to medical expenses and sick leaves. On some of the most slippery days, the number of slipping injuries can be so high that the hospital emergency departments are crowded with patients requiring surgery. The severity of slipping injuries typically increases with age. In addition, the number of slips and slip related injuries are more common among women than men. Finland has set a goal to increase the share of sustainable transport modes, such as walking and cycling, in the future. The aim is to reduce greenhouse gas emissions from transport and improve public health. Walking and cycling are to be the primary means of transport, especially for short distances in dense urban areas. In addition, the aim is to improve traffic safety and to develop walking and cycling infrastructure. This dissertation presents in which weather situations slips occur more than usual. In addition, the work presents a meteorological tool to help predicting weather conditions that cause pedestrian sidewalk slipperiness. Weather has a significant role in pedestrian’s wintertime slips and resulting injuries. In this dissertation, it has been investigated what are the weather situations that increase the risk of slipping and what is the spatio-temporal distribution of slips. Special attention has been given to situations with clearly more slips than usual, i.e. so called peak days of slipping injuries. The results show that snow and ice significantly increase the risk of slipping, and that most of the wintertime slips occur when the temperature is near zero degrees or slightly below it. This dissertation presents a numerical model predicting slipperiness from the pedestrian’s point of view. The model is developed at the Finnish Meteorological Institute. The thesis presents the physical principles of the model and how the slipperiness classification is implemented. The model is a tool for meteorologists to supports the decision making when issuing warnings about slippery sidewalk conditions. In addition, the model benefits winter road maintenance personnel and also public with better sidewalk condition and issued warnings. Climate change will have a major impact on future winters, especially in the northern latitudes. The winter season is shortened and near zero temperatures are becoming more frequent also during mid-winter, meaning more slippery conditions during that period. It is expected that the slip period will become shorter but at the same time more intense. Talvikauden liukastumisonnettomuudet ovat hyvin yleinen ongelma Suomessa niin kuin myös muissa maissa, joissa talviolosuhteet ovat yleisiä. Kyselytutkimusten perusteella noin joka kolmas suomalainen liukastuu talvisin ja noin 50 000 liukastuu niin pahasti, että joutuu käymään sairaalassa tai ensiavussa liukastumisvammojen vuoksi. Liukastumista aiheutuu inhimillistä kärsimystä sekä merkittäviä taloudellisia kustannuksia niin sairaanhoitokulujen kuin sairauspoissaolojen kautta. Pahimpina päivinä liukastumisia saattaa tapahtua niin paljon, että sairaaloiden päivystykset ruuhkautuvat leikkausta tarvitsevista potilaista. Liukastumisvammojen vakavuus kasvaa yleensä iän myötä. Lisäksi liukastumisia ja niistä aiheutuvia vammoja sattuu enemmän naisille kuin miehille. Suomi on asettanut tavoitteeksi lisätä kestävien liikennemuotojen, kuten kävelyn ja pyöräilyn, kulkutapaosuutta tulevaisuudessa. Tavoitteena on liikenteestä aiheutuvia kasvihuonepäästöjen vähentäminen sekä kansanterveyden parantaminen. Kävely ja pyöräily halutaan saada ensisijaiseksi liikkumismuodoksi etenkin tiiviillä kaupunkiseudulla lyhyillä matkoilla. Lisäksi tavoitteena on parantaa liikenneturvallisuutta sekä kehittää kävely- ja pyöräilyinfrastruktuuria. Tämä väitöskirjatyö esittelee säätilanteita, joissa liukastumisia sattuu tavanomaista enemmän. Lisäksi työssä esitellään meteorologinen työkalu, joka auttaa jalankulkuliukkautta aiheuttavien säätilanteiden ennustamisessa. Säällä on merkittävä vaikutus jalankulkijoiden talvikauden liukastumismääriin. Tässä väitöskirjatyössä on tutkittu, mitkä säätekijät lisäävät liukastumisriskiä ja miten liukastumismäärät jakautuvat alueellisti ja ajallisesti. Erityishuomio on tilanteissa, joissa liukastumisia sattuu selvästi tavanomaista enemmän, eli ns. liukastumisten piikkipäivissä. Tulokset osoittavat, että lumi ja jää lisäävät selvästi liukastumisriskiä ja suurin osa talvikauden liukastumisista sattuu silloin, kun lämpötila on nollan vaiheilla tai vähän pakkasen puolella. Tässä väitöskirjatyössä esitellään Ilmatieteen laitoksella kehitetty numeerinen malli, joka ennustaa jalkakäytävien liukkautta. Työ esittelee mallin fysikaalisen toiminnan ja sen, miten liukkauden mallintaminen on toteutettu. Malli toimii päivystävien meteorologien apuvälineenä ja päätöksenteon tukena, kun annetaan varoituksia erittäin liukkaista jalkakäytävistä. Meteorologien lisäksi mallista hyötyvät myös kaupungin teiden talvikunnossapito sekä varoitusten kautta myös kansalaiset. Ilmastonmuutos tulee vaikuttamaan voimakkaasti tulevaisuuden talviin etenkin pohjoisilla leveyspiireillä. Talvikausi tulee lyhenemään ja nollan läheisiä lämpötiloja ennustetaan olevan tulevaisuudessa enemmän. Tämä tarkoittaa, että liukkautta esiintynee tulevaisuudessa enemmän myös keskitalvella. On odotettavissa, että liukastumiskausi tulee muuttumaan lyhyemmäksi mutta samalla intensiivisemmäksi.

Sweden and Finland have both investigated underground thermal energy storage for nearly two decades, and have similar bedrock - the Fenno-Scandian granitic rocks. This article is a review of work performed in the field of combined rock cavern and borehole heat stores, concerned with construction technology, costs and design principles. One example is an asymmetric store, in the form of 40-60 m long horizontal boreholes between two rock caverns, with the caverns themselves comprising only about 10% of the total storage volume. This design has a specific cost of 0.40 MUSD/GWh and 0.24 MUSD/GWh for storage capacities of 6 GWh and 36 GWh respectively. Half of the total construction cost relates to the rock cavern part of the store.

The high resistivity and stiffness of granitic rocks make them to be excellent media for the propagation of electromagnetic and seismic waves. Permeable fractures reflect and attenuate the wave energy. Both surface and down-hole probes have been used at several sites. The examples present the technical advances from the shallow high-resolution seismics with large ranges of investigation to the very precise ground penetration radar techniques. Some of the mapped fractures are characterized by hydrogeological pumping tests and geophysical borehole logging.