Effects of solar wind variations on the magnetosphere

The solar wind is a continuous plasma flow from the Sun into the interplanetary space. It consist of large number of charged particles that carry the solar magnetic field with it. When the solar wind reaches the Earth, it interacts with the terrestrial magnetic field and creates a magnetosphere around our planet. At times, significant plasma and energy transfer occurs from the solar wind into the magnetosphere causing strong disturbances to the Earth’s inner magnetic field. The solar wind is often considered to be a single fluid that has macroscopic measurable parameters like velocity, density, pressure and magnetic field. These parameters have a different role in controlling the solar wind-magnetosphere coupling and thus, the relative and absolute variations of the parameters affects to the magnetospheric response. The motivation for this thesis stems from the need to improve our understanding on the solar wind-magnetosphere coupling, and thus, ultimately the space weather forecasting ability. The thesis consists of four peer-reviewed scientific publications and introduction. The main objectives were to study the coupling efficiency of different large-scale solar wind structures and how the efficiency varies with the geomagnetic latitude. This thesis also studies how the solar wind parameters control the plasma convection in the high-latitude magnetosphere. All four publications are statistical studies that combine in-situ solar wind measurements combined with the ground-based magnetometer data. This thesis gives significant new insight on how different solar wind parameters affect the magnetospheric response. The published articles suggest that the strongest geomagnetic disturbances are caused by the solar wind structures with the combination of the high geoeffective electric field, and high solar wind velocity and dynamic pressure. Such conditions are found generally from sheath regions of coronal mass ejections. The published articles also show new observational features of well-known phenomenon, called the polar cap potential saturation, that decreases coupling between the solar wind and magnetosphereAuringosta peräisin olevaa sähköisesti varautuneiden hiukkasten virtausta, joka kuljettaa mukanaan Auringon magneettikenttää, kutsutaan aurinkotuuleksi. Aurinkotuulen plasman vuorovaikutuksesta Maan magneettikentän kanssa muodostuu alue, jota kutsutaan magnetosfääriksi. Ajoittain vuorovaikutus johtaa myös plasman ja energian siirtymiseen aurinkotuulesta magnetosfääriin. Tämän kytkennän seurauksena Maan magneettikentässä havaitaan muutoksia, joita kutsutaan yleisesti geomagneettisiksi häiriöiksi. Geomagneettisia häiriöitä voi esiintyä paikallisesti esimerkiksi korkeilla leveyspiireillä tai häiriöitä voidaan mitata samanaikaisesti koko planeetalla. Aurinkotuulelle voidaan määrittää erilaisia makroskooppisia parametrejä kuten esimerkiksi nopeus, tiheys, magneettikentän arvo ja paine. Näillä parametreillä on erilainen vaikutus aurinkotuuli-magnetosfäärikytkentään, joten muutokset niiden suhteellisissa ja absoluuttisissa voimakkuuksissa aiheutavat erilaisen vasteen magnetosfäärissä Tämä väitöskirja käsittelee aurinkotuulen eri parametrien vaikutusta magnetosfäärin. Väitöskirja koostuu neljästä vertaisarvioidusta julkaisusta ja johdannosta. Väitöskirja tutkii erityisesti, kuinka plasmaominaisuuksiltaan erilaiset aurinkotuulen suuren mittakaavan rakenteet vaikuttavat aurinkotuuli-magnetosfääri -kytkennän tehokkuuteen, millainen vaikutus eri rakenteilla on eri leveyspiirien häiriöihin sekä mitkä aurinkotuulen parametrit kontrolloivat magnetosfäärin napa-alueen dynamiikkaa. Tässä väitöskirjassa olevat tutkimusartikkelit ovat luonteeltaan tilastollisia ja perustuvat sekä avaruusluotaimien tekemiin suoriin havaintoihin Maan lähiavaruudessa että maanpäällisten magnetometrien magneettikenttämittauksiin. Tässä väitöskirjassa osoitettiin, että aurinkotuulen koostumuksella on merkittävä vaikutus magne- tosfäärin vasteeseen. Tutkimusten perusteella aurinkotuulen rakenteet, joilla on suuren geoefektiivisen sähkökentän lisäksi korkea paine ja suuri nopeus, ajavat kaikkein tehokkaimmin suuria geomagneettisia häiriöitä verrattuna rakenteisiin, joilla on suuri sähkökenttä ja voimakas magneettikenttä

Additions to the diversity of lichens and lichenicolous fungi living on decaying wood in Finland.

Peer reviewe

Mutual Impedance Probe in Collisionless Unmagnetized Plasmas With Suprathermal Electrons—Application to BepiColombo

Context: Mutual impedance experiments are active electric probes providing in-situ space plasma measurements. Such active experiments consist of a set of electric antennas used as transmitter(s) and receivers(s) through which various dielectric properties of the plasma can be probed, giving therefore access to key plasma parameters such as, for instance, the electron density or the electron temperature. Since the beginning of the space exploration, such active probes have been launched and operated in Earth's ionospheric and magnetospheric plasmas. More recently and in the coming years, mutual impedance probes have been and will be operated onboard exploratory planetary missions, such as Rosetta, BepiColombo and JUICE, to probe the cometary plasma of 67P/Churyumov-Gerasimenko, the Hermean and the Jovian magnetospheres, respectively.Aims: Some analytic modeling is necessary to calibrate and analyse mutual impedance observations in order to access to macroscopic bulk plasma quantities. In situ particle observations from various space missions have confirmed that space plasmas are out of local thermodynamic equilibrium. This means that particle velocity distributions can be far from a Maxwellian distribution, exhibiting for instance temperature anisotropies, beams or a suprathermal population. The goal of this paper is to characterize the effect of suprathermal electrons on the instrumental response in order to assess the robustness of plasma diagnostics based on mutual impedance measurements in plasmas characterized by a significant amount of suprathermal particles.Methods: The instrumental response directly depends on the electron velocity distribution function (evdf). In this work, we choose to model suprathermal electrons by considering different approaches using: (i) a kappa evdf, (ii) a double-Maxwellian evdf or (iii) a mix of a Maxwellian evdf and a kappa evdf. For each case, we compute the spatial distribution of the electrostatic potential induced by the transmitters, discretized and modeled here as an ensemble of pulsating point charges.Results: We apply our modeling by building synthetic mutual impedance spectra of the PWI/AM2P probe, lauched in October 2018 onboard the Mercury Magnetospheric Orbiter (MIO/MMO) spacecraft of the BepiColombo exploratory space mission, in order to calibrate and analyse the future electron observations in the plasma environment of Mercury

Forecasting auroras from regional and global magnetic field measurements

We use the connection between auroral sightings and rapid geomagnetic field variations in a concept for a Regional Auroral Forecast (RAF) service. The service is based on statistical relationships between near-real-time alerts issued by the NOAA Space Weather Prediction Center and magnetic time derivative (dB / dt) values measured by five MIRACLE magnetometer stations located in Finland at auroral and sub-auroral latitudes. Our database contains NOAA alerts and dB / dt observations from the years 2002-2012. These data are used to create a set of conditional probabilities, which tell the service user when the probability of seeing auroras exceeds the average conditions in Fennoscandia during the coming 0-12 h. Favourable conditions for auroral displays are associated with ground magnetic field time derivative values (dB / dt) exceeding certain latitude-dependent threshold values. Our statistical analyses reveal that the probabilities of recording dB / dt exceeding the thresholds stay below 50% after NOAA alerts on X-ray bursts or on energetic particle flux enhancements. Therefore, those alerts are not very useful for auroral forecasts if we want to keep the number of false alarms low. However, NOAA alerts on global geomagnetic storms (characterized with K-p values > 4) enable probability estimates of > 50% with lead times of 3-12 h. RAF forecasts thus rely heavily on the well-known fact that bright auroras appear during geomagnetic storms. The additional new piece of information which RAF brings to the previous picture is the knowledge on typical storm durations at different latitudes. For example, the service users south of the Arctic Circle will learn that after a NOAA ALTK06 issuance in night, auroral spotting should be done within 12 h after the alert, while at higher latitudes conditions can remain favourable during the next night.Peer reviewe

Russian geomagnetic recordings in 1850–1862 compared to modern observations

We analyse geomagnetic recordings at four subauroral and midlatitude Russian observatories in 1850–1862. The data consist of spot readings made once in hour of the north and east components of the magnetic field. We use the hourly change of the horizontal field vector as the measure of activity. We compare these values to data from modern observatories at corresponding magnetic latitudes (Nurmijärvi, Finland, magnetic latitude ~57 N; Tartu, Estonia, ~54.5 N; Dourbes, Belgium, ~46 N) by reducing their data to the 1-h format. The largest variations at the Russian observatories occurred during the Carrington storm in September 1859 and they reached about 1000 nT/h, which was the instrumental off-scale limit. When the time stamp for the spot readings happens to be optimal, the top variation in the Nurmijärvi data is about 3700 nT/h (July 1982), and at Tartu the maximum is about 1600 nT/h (November 2004). At a midlatitude site Nertchinsk in Russia (magnetic latitude ~45 N), the variation during the Carrington storm was at the off-scale limit, and exceeded the value observed at Dourbes during the Halloween storm in October 2003. At Nertchinsk, the Carrington event was at least four times larger than any other storm in 1850–1862. Despite the limitations of the old recordings and in using only hourly spot readings, the Carrington storm was definitely a very large event at midlatitudes. At higher latitudes, it remains somewhat unclear whether it exceeds the largest modern storms, especially the one in July 1982

Perunan sadetuksen hallinta -raportti

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Perunan sadetuksen hallinta

Perunan vedentarve on muita viljelykasveja suurempi. Kasvukauden aikainen kuivuus aiheuttaa sadon määrän alenemista ja laadun heikkenemistä. Perunan sadetuksen hallinta -hankkeen tavoitteena oli tuottaa käytännön perunantuotantoon soveltuvaa tietoa sadetuksen satovaikutuksista, työmenekistä ja kannattavuudesta. Kenttäkokeissa selvitettiin sadetuksen vaikutuksia perunan kehitykseen, satoon ja laatuun. Kokeissa ei havaittu sadetuksella olevan vaikutuksia kasvuston kehittymiseen. Mukulalukumäärää sadetus sen sijaan lisäsi. Sadetus lisäksi nopeutti mukulasadon kehitystä kasvukauden puolivälissä, mutta lopullisen sadon ja tärkkelyssadon määrään sadetuksella ei tässä tutkimuksessa havaittu olevan vaikutusta. Sadetus lisäsi terveiden mukuloiden osuutta sadossa; sadettamattomissa ruuduissa oli seittirupisia mukuloita huomattavasti enemmän. Vuonna 2011 annettu lisätyppilannoitus hidasti kasvuston tuleentumista. Typpilisäys nosti sadon määrää ja suurempien mukuloiden osuutta sadossa, mutta onttoja tai keskeltä ruskeita oli enemmän. Typpilisäys nosti myös tärkkelysprosenttia ja tärkkelyssadon määrää. Kenttäkokeissa seurattiin sadetuksen vaikutuksia maan kosteuteen ja ravinnetilaan. Sadetetut alueet olivat sadettamattomia kosteampia kaikissa syvyyksissä. Käytetyt sadetusmenetelmät vaikuttivat maan kosteuteen samalla tavalla, eikä menetelmien välillä havaittu eroja. Kenttäkokeet toteutettiin kasvukausina 2010 ja 2011. Molempina vuosina luontainen sadanta oli niin runsasta, ettei sadetuksesta saatavaa hyötyä voitu selkeästi todentaa. Hankkeessa selvitettiin lisäksi sadetukseen käytettävien jokivesien laatua tärkeillä perunantuotantoalueilla sekä veden puhdistukseen tarkoitettujen menetelmien toimivuutta sadetusveden puhdistuksessa. Tulokset osoittivat käytetyn AOT-laitteiston puhdistavan vettä sekä perunalle tyvimätää aiheuttavista Dickeya spp -bakteereista että ihmisille haitallisista koliformisista bakteereista.Potato water demand is greater than that of the other crops in Finland. During the growing season, lack of water causes yield and quality losses.The aim of the project Management of irrigation in Finnish potato production was to produce practical knowledge of the effects of irrigation on potato crop, working hours and profitability. The effects of irrigation on potato development, yield and quality was investigated in field trials. In these trials, irrigation did not have any effect on potato stem development. However, irrigation did increase the number of tubers and speeded up the development of the yield in the mid of season. There were no differences in total yields nor starch yields between treatments. Irrigation increased the proportion of healthy tubers in yield, mainly because there was significantly more black scurf (Rhizoctonia solani) infected tubers in non-irrigated plots. In the second year we also tested the effect of extra nitrogen fertilizing on potato. Nitrogen supplement during early stage of tuber development delayed stem ripening. It also increased tuber yield and size, starch content and starch yield but reduced tuber quality by increasing internal defects. Soil moisture and nutrient content were also monitored. In the irrigated areas soil water content was higher in all depths (10 50 cm). Both gun (sprinkler) and boom irrigation methods had similar effects on soil moisture and no differences were observed between these methods. Field trials were carried out in growth periods of 2010 and 2011. In both years the natural rainfall was so heavy that the benefits of irrigation could not been clearly verified. We investigated the quality of river water in major potato production areas in Northern Ostrobothnia and also tested the effectiveness of different water purification methods to bacterial pathogens of potato. The results showed decrease in the total number of Dickeya bacteria (Ech 1A) which causes blackleg on potato and coliform bacteria which is harmful to human health, as the water circulated through the AOT water purification system.vo

Bakteeritaudinaiheuttajien tarkennettu tunnistus mikrosirudiagnostiikalla

Monien maa- ja elintarviketalouden kannalta merkittävien bakteeritaudinaiheuttajien luotettava tunnistus on ongelmallista. Näihin lukeutuvat perunan uusi, maa- ja siemenlevintäinen taudinaiheuttaja pohjanrupibakteeri (Streptomyces turgidiscabies), voimakasta hermomyrkkyä tuottava, vakavia ruokamyrkytyksiä ja halvauksia aiheuttava, elintarvikkeissa kulkeutuva Clostridium botulinum, sekä ihmisille tautia aiheuttavat enterohemorragiset Escherichia coli -bakteerit (EHEC-bakteerit; zoonoosi-taudinaiheuttajat), joiden tärkeimpänä lähteenä pidetään nautoja. Sopivan diagnostiikan puuttuessa edellä mainittuja, tauteja aiheuttavia bakteerikantoja ja -lajeja ei voida erottaa haitattomista, joita osa näytteiden mikrobeista edustaa. DNA-mikrosirut edustavat uutta diagnostista lähestymistapaa. Mikrosirulla tapahtuva tunnistus antaa poikkeuksellisen laajat mahdollisuudet mikrobin kuvailun yksityiskohtaisuudelle. Siten esim. taudinaiheuttamiskykyyn tarvittavien geenien yhdistelmää tai taudinaiheuttajalle ominaisia, minimaalisia geneettisiä eroja voidaan hyödyntää kokonaisuutena tunnistuksessa. Tämän hankkeen keskeisenä tavoitteena oli DNA-mikrosirutekniikan käyttöönottaminen diagnostiikassa. Koska menetelmä oli hankkeen alkaessa kansainvälisestikin ottaen uusi ja vasta kehitteillä, hankkeessa tukeuduttiin neljän tutkimuslaboratorion yhteistyöhön mahdollisimman nopean etenemisen varmistamiseksi. Soveltavan biologian laitoksen kasvipatologian laboratorio (Helsingin yliopisto, HY) koordinoi hanketta ja keskittyi perunan bakteeritaudinaiheuttajiin. Elintarvike- ja ympäristöhygienian laitos (HY) tutki ruokamyrkytysbakteereja. Elintarviketurvallisuusvirasto Eviran mikrobiologian tutkimusyksikkö tutki puolestaan EHEC-bakteereja. Mikrosirukokeet tehtiin Biotekniikan instituutin (HY) mikrosirulaboratoriossa, joka toimi teknologisena asiantuntijana. Hankkeeseen palkattiin yhteinen bioinformaatikko kehittämään tulosten käsittelyssä tarvittavia menetelmiä. Tutkimuksen lopullisena tavoitteena oli edistää elintarviketurvallisuutta, tuotantoeläinten terveyttä, elintarviketuotannossa käytettävien materiaalien hygieniaa sekä perunan kasvinsuojelua. Tutkimuksissa edettiin alun teknisten vaikeuksien jälkeen nopeasti, kun uusi mikrosirujen valmistusteknologia tuli käyttöön. Hankkeen tulokset edustavat tieteellisesti uudenaikaista lähestymistapaa bakteerien tyypittämiseen. Mikrosiruteknologian avulla oli mahdollista erotella kaikki perunalla merkittävät, Suomessa tavattavat bakteeritaudinaiheuttajat. Mikrosiruanalyysit paljastivat joukon C. botulinum:in geenejä, joiden perusteella bakteerikannat voitiin jakaa proteolyyttisten ominaisuuksien mukaisesti kahteen ryhmään ja kehittää niiden tunnistukseen nopea PCR-testi. Samalla periaatteella voitiin erotella tunnetusti patogeenisiä ja mahdollisesti patogeenisiä E. coli –kantoja. Tulokset veivät eteenpäin taudinaiheuttamiskykyyn liittyvien monimutkaisten ilmiöiden tutkimusta ja tuottivat diagnostiikassa sovelluskelpoisia tuloksia

Maatalouden ympäristötuen vaikuttavuuden seurantatutkimus (MYTVAS 3) : loppuraportti

Since 1995, agri-environmental support partly funded by the EU has formed the core of Finland’s agri-environmental policy. This system has had a variety of impacts on the relationship between agriculture and the environment. Today’s agri-environmental support is one of the packages included in the Rural Development Programme for Mainland Finland (2007–2013/2014), which both in itself and through the underlying EU legislation requires monitoring of the impacts of the measures implemented. The study monitoring the impact of the 2nd Finnish agri-environmental scheme (MYTVAS 3), which ran from 2008 to 2013, forms part of this monitoring. The MYTVAS 3 monitoring study was also financed by the Ministry of the Environment. The monitoring study was carried out by a consortium coordinated by MTT Agrifood Research Finland and including the Finnish Environment Institute (SYKE), the University of Helsinki, the Finnish Game and Fisheries Research Institute and the University of Turku.The purpose of the MYTVAS 3 monitoring study was to find out how agri-environmental support and its various measures have affected the state of the environment in agricultural areas, how agri-environmental support has affected the potential for farming and how agri-environmental support should be developed to increase its impact. The monitoring focused on the impacts of agri-environmental support on the nutrient load from agriculture on the waterways and on biodiversity. When evaluating the findings presented, we should remember that while monitoring data shows that something happened, it does not necessarily explain what caused it. It is not always possible to show that particular developments were a specific outcome of the current agri-environmental support system and the implementation of its measures. The delay between a measure and its observed impact is often long, and the cause-and-effect relationships are complicated and partly unknown. Also, other agricultural policy and fluctuations on the market may affect the state of the agricultural environment directly or indirectly.The monitoring data show that agri-environmental support has not had a detrimental impact on the potential for farming. Despite a slight increase in the incidence of weeds, they do not cause problems of the kind that would require amendments to the content of agri-environmental measures. Carbon levels in the surface stratum of arable land seems to be continuing their slow decline, and there is still need for measures to preserve organic material in the soil.Compliance with the fertilisation limits in the agri-environmental support system would seem to have had very little impact on crop quality. Variations in the weight and protein content per hectolitre and per 1,000 seeds were of the same order between 2006 and 2012 as they were between 1995 and 2005. Crop quantities have also not been noticeably affected by compliance with the fertilisation limits. Average crop yields remained stable between 1986 and 2013, and no clearly different crop years were observed in the 2000s. It is possible, however, that the lower fertilisation levels could have lowered crop potential in the years with advantageous weather conditions in the 2000s and that protein contents have been lower in advantageous years.The monitoring data also show that the nutrient load potential of agriculture, measured by nutrient balances, has decreased continuously for nitrogen and particularly for phosphorus. The decrease in the nutrient load potential is due above all to a decrease in the use of synthetic fertilisers. The decline in nitrogen fertilisation has bottomed out in recent years, and low protein levels measured in high crop yield years show that there is no point in further reducing nitrogen fertilisation. Optimising nitrogen fertilisation according to how advantageous the growing season is and effectively using the soluble nitrogen in cattle manure are key measures in achieving reasonable nitrogen balances and good crop quality despite fluctuations in growing season conditions. New crop variants have been found to make more efficient use of nitrogen than old ones, and thus the introduction of new variants should be promoted. Despite the decrease in the nutrient balances, there are indications that nutrient loads in runoff water from domestic animal production sites are becoming an increasing problem. Indeed, the fundamental problem with the nutrient load from agriculture is the diversification of livestock farming and crop farming, which has made it more difficult to use nutrients appropriately. Therefore attention must be paid to measures that both boost the use of nutrients in manure and reduce the levels of nutrients that end up in manure. Based on nutrient load monitoring in the catchment areas of rivers, the phosphorus load per hectare of cropland has decreased in each programme period, being about 80% of the level of the first period (1995–1999) in the third period (2007–2013). Because of the increase in the area of cropland, the nitrogen load on waterways from agriculture continued to grow during the second programme period (2000–2006) but peaked in the third (2007–2013). A similar trend was found in the nitrogen load per hectare of cropland.The most important threat to biodiversity is caused by the development of landscape structure, typically involving a decrease in the number of open or half-open areas excluded from actual cultivation. The consequence of the clearing of margins and ecological islands located in crop fields, drainage measures aimed at increasing arable land and all rationalisation of cultivated areas is the diminishing of exactly those areas that are the most important from the perspective of the biodiversity of the agricultural environment. However, the measure-specific findings in the monitoring study show that biodiversity benefits have been locally achieved where measures have been implemented on a broad enough scale (biodynamic farming, traditional biotopes, wetlands, buffer zones, green fallow / nature management areas). Particular care should therefore be taken that all cultivated land continues to have a sufficient percentage of non-cultivated areas, whether they be natural meadows, nature management areas, biodiversity strips, buffer zones, filter strips, headlands, ecological islands, etc. Including the rather popular nature management areas as a new voluntary measure under basic measures was a significant contribution to biodiversity.Regarding the rural landscape, it may be noted that by visual inspection the area of cropland has remained largely unchanged, at the level of the landscape as a whole it is far more common for the landscape to become more closed than to become more open. This trend was also observed in the visual inspection of traditional biotopes, even if the openness of the meadows monitored largely remained unchanged.The only measures that directly address the reduction of gaseous emissions in the agri-environmental support system are the longterm grass cultivation on peat fields and special aid agreements for slurry injection in cropland. While other measures have indirectly affected gaseous emissions, the impact of agri-environmental support as a whole on reducing gaseous emissions from agriculture has been negligible. In general, we may conclude that the goals, content and support levels of agri-environmental support measures must be increasingly adapted and customised by region, by type of farming and by farm, because both the state of the agricultural environment and the needs of society differ greatly between different types of rural area