Matalapaineiden kehitykseen vaikuttavat tekijät korkeustendenssilaskelmien valossa

Tässä työssä tutkittiin matalapainekehitykseen vaikuttavia eri tekijöitä korkeustendenssien avulla. Korkeustendenssi eli geopotentiaalikorkeuden aikaderivaatta on suure, jonka arvo kertoo miten painepinnan korkeus muuttumassa. Tavoitteena oli selvittää, millaisia ovat eri pakotteiden aiheuttamien korkeustendenssien keskimääräiset pystyjakaumat keskileveysasteiden matalapaineiden keskustassa ja miten jakaumat eroavat voimistuvien ja heikkenevien syklonien välillä. Lisäksi pakotteiden tuottamia korkeustendenssejä tutkittiin laajemmin yksittäisen matalapaineen yhteydessä. Korkeustendenssien laskentaan käytettiin Zwack-Okossi-tendenssiyhtälöä, joka ottaa huomioon kaikki korkeustendensseihin vaikuttavat tekijät. Yhtälön sisältämät pystyliikkeet laskettiin yleisen omegayhtälön avulla. Korkeustendenssikenttä jaettiin eri pakotteiden aiheuttamiksi, jotka olivat pyörteisyyden advektio, lämpötilan advektio, kitka, diabaattinen lämmitys ja ageostrofinen pyörteisyystendenssi. Pyörteisyyden advektio jaettiin vielä divergentin ja ei-divergentin tuulen aiheuttamiin osuuksiin. Tutkimuksessa käytettiin OpenIFS-mallidataa pohjoisen pallonpuoliskon keski- ja korkeilta leveysasteilta talvikauden ajalta. Tältä ajalta otokseen poimittiin kaikki mallin simuloimat matalapaineet. Ne jaettiin pintapaineen tendenssin perusteella voimistuviin ja heikkeneviin tapauksiin, käyttäen raja-arvona näille ± 6 hPa/12h. Suurimman kontribuution syveneviin pintamataliin tuotti diabaattinen lämmitys. Pääosin vesihöyryn tiivistymisestä johtuva lämmitys tuotti negatiivisen korkeustendenssin 90 %:ssa voimistuvista matalapaineista. Lämpötilan advektio oli myös tehokas matalapaineita syventävä pakote. Voimistuvissa sykloneissa sen kontribuutio oli pakotteista toiseksi suurin, kun taas heikkenevissä matalapaineissa sen vaikutus oli lähes olematon. Pyörteisyyden advektion tuottama korkeustendenssi oli voimistuvien pintamatalien keskustassa keskimäärin melko lähellä nollaa. Tämä johtui siitä, että divergentin ja ei-divergentin tuulen aiheuttamat korkeustendenssit kumosivat toinen toisensa vaikutusta. Divergentti osuus osoittautui pintamatalia heikentäväksi mekanismiksi, kun taas divergenssitön osuus syvensi niitä. Kitkan vaikutus odotetusti vaimensi matalapaineita. Ageostrofinen pyörteisyystendenssi puolestaan voimisti syveneviä ja heikensi täyttyviä sykloneita. Aikaisempiin tutkimuksiin verrattuna tässä työssä uutta oli se, että pystytuuli jaettiin osatekijöihinsä omegayhtälön avulla. Näin ollen se ei esiintynyt laskelmissa omana pakotteenaan. Lisäksi tässä tutkimuksessa tutkittiin matalapainekehitykseen vaikuttavia tekijöitä aiempaa täydellisemmin ja systemaattisemmin

Diagnostic Studies of Extratropical Cyclones in the Present and Warmer Climate

Liikkuvat matalapaineet ovat keski- sekä korkeiden leveysasteiden tärkeimpiä sääilmiöitä. Niiden ansiosta päivittäinen säämme on vaihtelevaa, mutta toisaalta voimakkaat matalapaineet voivat aiheuttaa vahinkoja yhteiskunnalle ja esimerkiksi metsätaloudelle myrskytuulien, tulvimisen tai lumisateiden takia. Keskileveysasteiden liikkuvat matalapaineet ovat myös tärkeä osa koko ilmakehän yleistä kiertoliikettä, koska ne kuljettavat liikemäärää ja esimerkiksi tasaavat päiväntasaajan ja korkeiden leveysasteiden suurta lämpötilaeroa. Ilmaston lämpenemisen myötä matalapaineiden kasvuympäristö tulee muuttumaan. Esimerkiksi lämpötilan noususta johtuva ilmakehän kosteussisällön kasvu voimistaa pilvissä tapahtuvaa latentin lämmön vapautumista, mikä vaikuttaa myrskyjen voimakkuuteen, voimistumisnopeuteen ja lopulta myös niiden aiheuttamiin tuhoihin. On siis tärkeää tutkia tarkasti mitä vaikutuksia ilmastonmuutoksella on liikkuvien matalapaineiden dynamiikkaan. Tässä tutkimuksessa kehitettiin diagnostinen työkalu jolla voitiin tutkia matalapaineissa ilmakehän pystyliikkeen sekä geopotentiaalikorkeuden ja suhteellisen pyörteisyyden muutosnopeuden fysikaalisia syitä. Tämän tiedon avulla saadaan selville miten adiabaattinen dynamiikka ja toisaalta diabaattiset prosessit vaikuttavat matalapaineiden kehitykseen, ja mikä on näiden tekijöiden keskinäinen suuruusluokka. Työssä tutkittiin sekä ideaalista, oppikirjamaista matalapainetta, sekä todellista, hurrikaanista muuntautunutta matalapainetta. Idealisoidussa tapauksessa sekä adiabaattiset että diabaattiset prosessit olivat voimakkaita, kun taas myrsky joka muuntui hurrikaanista keskileveysasteiden matalapaineeksi osoittautui vahvasti diabaattiseksi. Tällainen tieto eroavaisuuksissa myrskyjen dynamiikassa on keskeistä ilmastonmuutoksen aikakaudella, erityisesti kasvavan ilmakehän kosteussisällön takia. Väitöskirjatyössä tutkittiin myös miten keskileveysasteiden matalapaineiden ominaisuudet ja rakenne muuttuu ilmaston lämpenemisen myötä. Tulosten mukaan neljän asteen lämpeneminen kasvatti matalapaineisiin liittyvää sateisuutta jopa 50 %. Havaittiin myös että sadealue siirtyi lämpenemisen myötä kauemmaksi myrskyn keskustasta. Lisäksi huomattiin että myrskyjen dynamiikka riippuu eri tavalla ala- ja yläilmakehän lämpötilagradienteista, jotka muuttuvat pohjoisella pallonpuoliskolla ilmaston lämmetessä. Alailmakehän lämpötilagradientin heikkeneminen vähensi matalapaineiden voimakkuutta hyvin selkeästi, kun taas yläilmakehän lämpötilagradientin kasvattaminen voimisti matalapaineita, mutta voimistumisen suuruus oli herkkä ilmakehän kosteussisällölle. Saatu tulos korostaa latentin lämmön vapautumista matalapaineiden kehityksessä.Extratropical cyclones are among the most important weather phenomena at mid- and high latitudes. They drive the weather variability on daily basis, and the passage of a strong extratropical cyclone can occasionally cause damage for society in general and, as a specific example, forestry due to strong winds, flooding and snow load. Furthermore, extratropical cyclones are a crucial component of the atmospheric general circulation due to their ability to transport large amounts of heat and momentum. Because of climate change, the environment in which extratropical cyclones form will change. For example, the increase of available moisture for extratropical cyclones with the warming enhances the latent heat release in the clouds, affecting thus potentially the intensity and deepening rate of extratropical cyclones, and eventually the impacts which are felt at the surface. Therefore, studying the various effects of climate change on the dynamics of extratropical cyclones is of great importance. In this thesis, a diagnostic method was developed to analyse the physical causes of vertical motion, geopotential height tendency and relative vorticity tendency within extratropical cyclones. Information on the physical causes gives insight into the relative contribution of different moist and dry processes to the evolution of extratropical cyclones. The thesis covers studies of both an idealized, traditional type of cyclone driven by both adiabatic and diabatic dynamics, and a real-world cyclone which was transitioned from a hurricane and was found to be strongly dependent on moist processes. Information on such dynamical differences is essential during the era of changing climate, when the atmospheric moisture content is continuously increasing due to global warming. Furthermore, the changes in the characteristics and structure of extratropical cyclones with the warming were investigated. In a model simulation in which sea surface temperatures were increased by 4 K, the precipitation associated with the cyclones increased up to 50 %, and the area of rainfall moved further away from the cyclone's centre. It was also discovered that extratropical cyclones tend to respond differently to the changes in lower-level and upper-level temperature gradient. The decrease of lower-level temperature gradient, as anticipated in northern mid-latitudes with climate change, tends to decrease the strength of extratropical cyclones in a robust way. The response of extratropical cyclones to the increase of upper-level temperature gradient seems to be, in turn, more sensitive to the presence of atmospheric moisture, which highlights the importance of mid-tropospheric latent heat release for the development of extratropical cyclones

Sensitivity of idealised baroclinic waves to mean atmospheric temperature and meridional temperature gradient changes

The sensitivity of idealised baroclinic waves to different atmospheric temperature changes is studied. The temperature changes are based on those which are expected to occur in the Northern Hemisphere with climate change: (1) uniform temperature increase, (2) decrease of the lower level meridional temperature gradient, and (3) increase of the upper level temperature gradient. Three sets of experiments are performed, first without atmospheric moisture, thus seeking to identify the underlying adiabatic mechanisms which drive the response of extra-tropical storms to changes in the environmental temperature. Then, similar experiments are performed in a more realistic, moist environment, using fixed initial relative humidity distribution. Warming the atmosphere uniformly tends to decrease the kinetic energy of the cyclone, which is linked both to a weaker capability of the storm to exploit the available potential energy of the zonal mean flow, and less efficient production of eddy kinetic energy in the wave. Unsurprisingly, the decrease of the lower level temperature gradient weakens the resulting cyclone regardless of the presence of moisture. The increase of the temperature gradient in the upper troposphere has a more complicated influence on the storm dynamics: in the dry atmosphere the maximum eddy kinetic energy decreases, whereas in the moist case it increases. Our analysis suggests that the slightly unexpected decrease of eddy kinetic energy in the dry case with an increased upper tropospheric temperature gradient originates from the weakening of the meridional heat flux by the eddy. However, in the more realistic moist case, the diabatic heating enhances the interaction between upper- and low-level potential vorticity anomalies and hence helps the surface cyclone to exploit the increased upper level baroclinicity.Peer reviewe

The use of the Brief Child Abuse Potential Inventory in the general population in Finland

Correction: Volume: 37 Issue: 2 Pages: 249-255 DOI: 10.1080/02813432.2019.1608629Objective: The purpose of this research was to analyze psychometric information in the Brief Child Abuse Potential Inventory (BCAP) in a Finnish general population sample. Design: A self-report survey of parents in a primary health care setting and a hospital setting was used to evaluate the use of the BCAP. Setting: The study population consisted of parents who were visiting one of the following contexts: a primary maternity health care clinic, a child health care clinic, and the maternity outpatient clinic, various pediatric outpatient clinics, the general pediatric ward, the pediatric surgical ward, or the neonatal intensive care unit in a hospital setting. Subjects: The BCAP was given to parents at the 30-34th week of pregnancy, when the child was 5 months old or all parents depending on the context. The BCAP was delivered to 759 parents. The final size of the sample was 453 respondents. Main outcome measure: The BCAP, which consisted of 25 items to screen child abuse potential and nine items for evaluation of respondent validity. Results: The internal consistency of the Abuse Risk Scale was good (.770), and the validity scales worked well. The factor structure mirrors with the original factors structure. Conclusion: The psychometric properties of the BCAP reported in the analysis suggest that the BCAP could be a valid instrument to detect child abuse potential in the general population in Finnish health care settings. However, among Finnish respondents there is very little variation in some parts of the measure, which suggests that further research should assess the validity of the instrument in representative samples. Further analysis is also needed to evaluate the correct classification rate of the BCAP.Peer reviewe

The characteristics and structure of extra-tropical cyclones in a warmer climate

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The summer 2018 heatwave in Finland

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The extratropical transition of Hurricane Ophelia (2017) as diagnosed with a generalized omega equation and vorticity equation

Hurricane Ophelia was a category 3 hurricane which underwent extratropical transition and made landfall in Europe as an exceptionally strong post-tropical cyclone in October 2017. In Ireland, Ophelia was the worst storm in 50 years and resulted in significant damage and even loss of life. In this study, the different physical processes affecting Ophelia’s transformation from a hurricane to a mid-latitude cyclone are studied. For this purpose, we have developed software that uses OpenIFS model output and a system consisting of a generalized omega equation and vorticity equation. By using these two equations, the atmospheric vertical motion and vorticity tendency are separated into the contributions from different physical processes: vorticity advection, thermal advection, friction, diabatic heating, and the imbalance between the temperature and vorticity tendencies. Vorticity advection, which is often considered an important forcing for the development of mid-latitude cyclones, is shown to play a small role in the re-intensification of the low-level cyclone. Instead, our results show that the adiabatic upper-level forcing was strongly amplified by moist processes, and thus, the diabatic heating was the dominant forcing in both the tropical and extratropical phases of Ophelia. Furthermore, we calculated in more detail the diabatic heating contributions from different model parameterizations. We find that the temperature tendency due to the convection scheme was the dominant forcing for the vorticity tendency during the hurricane phase, but as Ophelia transformed into a mid-latitude cyclone, the microphysics temperature tendency, presumably dominated by large-scale condensation, gradually increased becoming the dominant forcing once the transition was complete. Temperature tendencies caused by other diabatic processes, such as radiation, surface processes, vertical diffusion, and gravity wave drag, were found to be negligible in the development of the storm.Hurricane Ophelia was a category 3 hurricane which underwent extratropical transition and made landfall in Europe as an exceptionally strong post-tropical cyclone in October 2017. In Ireland, Ophelia was the worst storm in 50 years and resulted in significant damage and even loss of life. In this study, the different physical processes affecting Ophelia's transformation from a hurricane to a mid-latitude cyclone are studied. For this purpose, we have developed software that uses OpenIFS model output and a system consisting of a generalized omega equation and vorticity equation. By using these two equations, the atmospheric vertical motion and vorticity tendency are separated into the contributions from different physical processes: vorticity advection, thermal advection, friction, diabatic heating, and the imbalance between the temperature and vorticity tendencies. Vorticity advection, which is often considered an important forcing for the development of mid-latitude cyclones, is shown to play a small role in the re-intensification of the low-level cyclone. Instead, our results show that the adiabatic upper-level forcing was strongly amplified by moist processes, and thus, the diabatic heating was the dominant forcing in both the tropical and extratropical phases of Ophelia. Furthermore, we calculated in more detail the diabatic heating contributions from different model parameterizations. We find that the temperature tendency due to the convection scheme was the dominant forcing for the vorticity tendency during the hurricane phase, but as Ophelia transformed into a mid-latitude cyclone, the microphysics temperature tendency, presumably dominated by large-scale condensation, gradually increased becoming the dominant forcing once the transition was complete. Temperature tendencies caused by other diabatic processes, such as radiation, surface processes, vertical diffusion, and gravity wave drag, were found to be negligible in the development of the storm.Peer reviewe

Survey of Component-Based Software Engineering within IoT Development

The Internet of Things (IoT) is a growing area in everyday life. New applications under the umbrella term IoT are being developed continuously. A typical IoT system consists of quite a large set of interchangeable components. In prototype development the Raspberry Pi and Arduino have become core components of wireless sensor network solutions. This research looks at how component-based software engineering (CBSE) and off-the-shelf components can be taken advantage of when defining IoT systems. We will attempt to identify the common properties of IoT systems and compare how well these properties relate to the CBSE component characteristics: composability, deployability, comprehensive documentation, independence, and standardization. The research methodology used in this study is a literature survey. The main results of the study show that CBSE is not widely used. There has been very little research on the software side of applications, as most studies have focused on describing the hardware side of implementations. The conclusion can be made that, in order for studies to be reproducible, the software side should be described in more detail.acceptedVersionPeer reviewe

OSKU - an Application for Collecting User Feedback on Living Conditions in Buildings

Reducing energy consumption is currently a very topical area of research, but perhaps it is more a question of optimizing rather than reducing consumption. Preserving optimal working and living conditions within buildings should also be considered in combination with energy usage. The global rise in temperature caused by climate change may bring requirements for additional cooling of buildings, even in geographical areas that have not needed cooling in the past. In Finland, the winter months will require buildings to be heated to provide a comfortable indoor environment even in the future. A multitude of sensors exist for measuring quantities such as carbon dioxide, relative humidity, and temperature, but how well do the values measured by sensors match the subjective feelings of the people living or working inside buildings? In an attempt to discover how people feel in their working environment, we developed an application called OSKU for collecting user feedback concerning indoor air quality, and tested it in two real-life locations (a daycare center and a school), which were also fitted with sensors. In this paper we will describe the application, the use cases, and give an example of how we compared the feedback with the measured sensor values.acceptedVersionPeer reviewe

Categorization of Digital Twins : A Literature Review of IoT and Industry

In recent years, the digital twin concept has gained traction in both academia and industry. But what is a digital twin? It is quite common to see many kinds of publications from scientific research to news articles on digital twins mentioning that there is no exact definition for the term. In this paper, we will go through the digital database of IEEE Xplore in an attempt to find out how the publications on digital twins use the term, and how the twins could be categorized and defined more clearly. Our focus is on literature that studies the digital twins within the context of Internet-of-Things (IoT) and industry. Our studies will show that there is indeed a need for a more standardized definition for the term, and that digital twin is often used as a blanket term to cover many systems, prototypes and implementations that may or may not be actual digital twins.Peer reviewe