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This paper describes impacts of and experiences from two co-creative innovation environments, the SmartRail Ecosystem and Mobility Lab Helsinki. These innovation environments are investigated and compared to see what similarities and differences the environments have, and furthermore, what kinds of gained benefits and other impacts the environments have produced for different actors. The paper discusses how impacts of ecosystems and enabling innovation collaboration can be evaluated and what is the value of co-creation environments.

CH4 simulations from the LPJ-GUESS, a process-based dynamic global vegetation model,was calibrated using the daily CH4 flux observations collected at Siikaneva wetlands ( Finland)from 2005 to 2014.Rao-Blackwellised modification ofAdaptive Metropolis MCMC sampling algorithm was used to calibrate the model. The code, data used to input the model and the data used to optimise the model are uploaded.

Recent climate change mitigation strategies rely on the reduction of methane (CH4) emissions. Carbon and hydrogen isotope ratio (δ13CCH4 and δ2HCH4) measurements can be used to distinguish sources and thus to understand the CH4 budget better. The CH4 emission estimates by models are sensitive to the isotopic signatures assigned to each source category, so it is important to provide representative estimates of the different CH4 source isotopic signatures worldwide. We present new measurements of isotope signatures of various, mainly anthropogenic, CH4 sources in Europe, which represent a substantial contribution to the global dataset of source isotopic measurements from the literature, especially for δ2HCH4. They improve the definition of δ13CCH4 from waste sources, and demonstrate the use of δ2HCH4 for fossil fuel source attribution. We combined our new measurements with the last published database of CH4 isotopic signatures and with additional literature, and present a new global database. We found that microbial sources are generally well characterised. The large variability in fossil fuel isotopic compositions requires particular care in the choice of weighting criteria for the calculation of a representative global value. The global dataset could be further improved by measurements from African, South American, and Asian countries, and more measurements from pyrogenic sources. We improved the source characterisation of CH4 emissions using stable isotopes and associated uncertainty, to be used in top-down studies. We emphasise that an appropriate use of the database requires the analysis of specific parameters in relation to source type and the region of interest. The final version of the European CH4 isotope database coupled with a global inventory of fossil and non-fossil δ13CCH4 and δ2HCH4 source signature measurements is available at https://doi.org/10.24416/UU01-YP43IN (Menoud et al., 2022a).

The reasons for spatial and temporal variation in methane emission from mire ecosystems are not fully understood. Stable isotope signatures of the emitted methane can offer clues to the causes of these variations. We measured the methane emission (FCH4) and 13C signature (δ13C) of emitted methane by automated chambers at a hemiboreal mire for two growing seasons. In addition, we used ambient methane mixing ratios and δ13C to calculate a mire-scale 13C signature using a nocturnal boundary-layer accumulation approach. Microbial methanogenic and methanotrophic communities were determined by a captured metagenomics analysis. The chamber measurements showed large and systematic spatial variations in δ13C-CH4 of up to 15 ‰ but smaller and less systematic temporal variation. According to the spatial δ13C–FCH4 relations, methanotrophy was unlikely to be the dominating cause for the spatial variation. Instead, these were an indication of the substrate availability of methanogenesis being a major factor in explaining the spatial variation. Genetic analysis indicated that methanogenic communities at all sample locations were able to utilize both hydrogenotrophic and acetoclastic pathways and could thus adapt to changes in the available substrate. The temporal variation in FCH4 and δ13C over the growing seasons showed hysteresis-like behavior at high-emission locations, indicative of time-lagged responses to temperature and substrate availability. The upscaled chamber measurements and nocturnal boundary-layer accumulation measurements showed similar average δ13C values of −81.3 ‰ and −79.3 ‰, respectively, indicative of hydrogenotrophic methanogenesis at the mire. The close correspondence of the δ13C values obtained by the two methods lends confidence to the obtained mire-scale isotopic signature. This and other recently published data on δ13C values of CH4 emitted from northern mires are considerably lower than the values used in atmospheric inversion studies on methane sources, suggesting a need for revision of the model input.

Emissions of biogenic volatile organic compounds (BVOCs) are a crucial component of biosphere-atmosphere interactions. In northern latitudes, climate change is amplified by feedback processes in which BVOCs have a recognized, yet poorly quantified role, mainly due to a lack of measurements and concomitant modeling gaps. Hence, current Earth system models mostly rely on temperature responses measured on vegetation from lower latitudes, rendering their predictions highly uncertain. Here, we show how tundra isoprene emissions respond vigorously to temperature increases, compared to model results. Our unique dataset of direct eddy covariance ecosystem-level isoprene measurements in two contrasting ecosystems exhibited Q10 (the factor by which the emission rate increases with a 10 °C rise in temperature) temperature coefficients of up to 20.8, that is, 3.5 times the Q10 of 5.9 derived from the equivalent model calculations. Crude estimates using the observed temperature responses indicate that tundra vegetation could enhance their isoprene emissions by up to 41% (87%)-that is, 46% (55%) more than estimated by models-with a 2 °C (4 °C) warming. Our results demonstrate that tundra vegetation possesses the potential to substantially boost its isoprene emissions in response to future rising temperatures, at rates that exceed the current Earth system model predictions., We are grateful to ICOS Sweden, the Abisko Scientific Research Station (ANS), and the Finse Alpine Research Centre for providing excellent logistics for the work, and we are grateful in particular to Mikkel Sillesen Matzen, John Hulth, Andreas Westergaard-Nielsen, and Rune Maigaard for field assistance and to Jutta Holst for assistance with data. High-frequency wind data from Abisko were provided by ICOS Sweden, which has been cofinanced by the Swedish Research Council (grant 2019-00205); Abisko-Stordalen has been hosted by ANS and SITES "Swedish Infrastructure for Ecosystem Sciences" (cofinanced by the Swedish Research Council). This research has been supported by the European Research Council (TUVOLU "Tundra Biogenic Volatile Emissions in the 21st Century", grant 771012) under the European Union’s Horizon 2020 research and innovation program, the Independent Research Fund Denmark/Natural Sciences (grant DFF–4181-00141), and the Danish National Research Foundation (CENPERM grant DNRF100). R.S. acknowledges a Ramón y Cajal grant (RYC2020-029216-I) funded by the Spanish Ministry of Science and Innovation and the State Research Agency (MCIN/AEI/10.13039/501100011033) and by the European Social Fund “ESF Investing in Your Future”. IDAEA-CSIC is a Severo Ochoa Centre of Research Excellence (MCIN/AEI, project CEX2018-000794-S). This work is a contribution to the strategic research initiative LATICE "Land–ATmosphere Interactions in Cold Environments" (Faculty of Mathematics and Natural Sciences, University of Oslo, project UiO/GEO103920) and was supported by the EMERALD "Terrestrial ecosystem–climate interactions of our EMERALD planet" project funded by the Research Council of Norway (project 294948).

This review presents how the boreal and the tropical forests affect the atmosphere, its chemical composition, its function, and further how that affects the climate and, in return, the ecosystems through feedback processes. Observations from key tower sites standing out due to their long-term comprehensive observations: The Amazon Tall Tower Observatory in Central Amazonia, the Zotino Tall Tower Observatory in Siberia, and the Station to Measure Ecosystem-Atmosphere Relations at Hyytiala in Finland. The review is complemented by short-term observations from networks and large experiments. The review discusses atmospheric chemistry observations, aerosol formation and processing, physiochemical aerosol, and cloud condensation nuclei properties and finds surprising similarities and important differences in the two ecosystems. The aerosol concentrations and chemistry are similar, particularly concerning the main chemical components, both dominated by an organic fraction, while the boreal ecosystem has generally higher concentrations of inorganics, due to higher influence of long-range transported air pollution. The emissions of biogenic volatile organic compounds are dominated by isoprene and monoterpene in the tropical and boreal regions, respectively, being the main precursors of the organic aerosol fraction. Observations and modeling studies show that climate change and deforestation affect the ecosystems such that the carbon and hydrological cycles in Amazonia are changing to carbon neutrality and affect precipitation downwind. In Africa, the tropical forests are so far maintaining their carbon sink. It is urgent to better understand the interaction between these major ecosystems, the atmosphere, and climate, which calls for more observation sites, providing long-term data on water, carbon, and other biogeochemical cycles. This is essential in finding a sustainable balance between forest preservation and reforestation versus a potential increase in food production and biofuels, which are critical in maintaining ecosystem services and global climate stability. Reducing global warming and deforestation is vital for tropical forests.

The reasons for spatial and temporal variation of methane emission from mire ecosystems are not fully understood. Stable isotope signatures of the emitted methane can offer cues to the causes of these variations. We measured the methane emission and 13C-signature of emitted methane by automated chambers at a temperate mire for two growing seasons. In addition, we used ambient methane mixing ratios and δ13C-CH4 to calculate a mire-scale 13C signature using a nocturnal boundary-layer accumulation approach. Microbial methanogenic and methanotrophic communities were determined by a captured metagenomics analysis. The chamber measurements showed large and systematic spatial variations in δ13C-CH4 of up to 15 ‰ but smaller and less systematic temporal variation. The trophic status of methanogenesis was the dominant factor explaining the spatial variation. Genetic analysis indicated that methanogenic communities at all sample locations were able to utilize both hydrogenotrophic and acetoclastic pathways and could thus adapt to trophic status. The temporal variation of methane emission and δ13C-CH4 over the growing seasons showed hysteresis-like behavior, indicative of time-lagged responses to temperature and trophic status. The up-scaled chamber measurements and nocturnal boundary-layer accumulation measurements showed similar average δ13C-CH4 values of -81.3 ‰ and -79.3 ‰, respectively, lending confidence to the use of mire scale isotopic signatures to be used in e.g. atmospheric inversion modelling of methane sources. The results obtained can constrain our theories on the variability of methane emission from mire ecosystems and be useful in development of numerical models of mire biogeochemistry.

This review presents how the boreal and the tropical forests affect the atmosphere, its chemical composition, its function, and further how that affects the climate and, in return, the ecosystems through feedback processes. Observations from key tower sites standing out due to their long-term comprehensive observations: The Amazon Tall Tower Observatory in Central Amazonia, the Zotino Tall Tower Observatory in Siberia, and the Station to Measure Ecosystem-Atmosphere Relations at Hyytiala in Finland. The review is complemented by short-term observations from networks and large experiments.The review discusses atmospheric chemistry observations, aerosol formation and processing, physiochemical aerosol, and cloud condensation nuclei properties and finds surprising similarities and important differences in the two ecosystems. The aerosol concentrations and chemistry are similar, particularly concerning the main chemical components, both dominated by an organic fraction, while the boreal ecosystem has generally higher concentrations of inorganics, due to higher influence of long-range transported air pollution. The emissions of biogenic volatile organic compounds are dominated by isoprene and monoterpene in the tropical and boreal regions, respectively, being the main precursors of the organic aerosol fraction.Observations and modeling studies show that climate change and deforestation affect the ecosystems such that the carbon and hydrological cycles in Amazonia are changing to carbon neutrality and affect precipitation downwind. In Africa, the tropical forests are so far maintaining their carbon sink.It is urgent to better understand the interaction between these major ecosystems, the atmosphere, and climate, which calls for more observation sites, providing long-term data on water, carbon, and other biogeochemical cycles. This is essential in finding a sustainable balance between forest preservation and reforestation versus a potential increase in food production and biofuels, which are critical in maintaining ecosystem services and global climate stability. Reducing global warming and deforestation is vital for tropical forests.

This review presents how the boreal and the tropical forests affect the atmosphere, its chemical composition, its function, and further how that affects the climate and, in return, the ecosystems through feedback processes. Observations from key tower sites standing out due to their long-term comprehensive observations: The Amazon Tall Tower Observatory in Central Amazonia, the Zotino Tall Tower Observatory in Siberia, and the Station to Measure Ecosystem-Atmosphere Relations at Hyytiäla in Finland. The review is complemented by short-term observations from networks and large experiments.The review discusses atmospheric chemistry observations, aerosol formation and processing, physiochemical aerosol, and cloud condensation nuclei properties and finds surprising similarities and important differences in the two ecosystems. The aerosol concentrations and chemistry are similar, particularly concerning the main chemical components, both dominated by an organic fraction, while the boreal ecosystem has generally higher concentrations of inorganics, due to higher influence of long-range transported air pollution. The emissions of biogenic volatile organic compounds are dominated by isoprene and monoterpene in the tropical and boreal regions, respectively, being the main precursors of the organic aerosol fraction.Observations and modeling studies show that climate change and deforestation affect the ecosystems such that the carbon and hydrological cycles in Amazonia are changing to carbon neutrality and affect precipitation downwind. In Africa, the tropical forests are so far maintaining their carbon sink.It is urgent to better understand the interaction between these major ecosystems, the atmosphere, and climate, which calls for more observation sites, providing long-term data on water, carbon, and other biogeochemical cycles. This is essential in finding a sustainable balance between forest preservation and reforestation versus a potential increase in food production and biofuels, which are critical in maintaining ecosystem services and global climate stability. Reducing global warming and deforestation is vital for tropical forests.

The Artic is exposed to faster temperature changes than most other areas on Earth. Constantly increasing temperature will lead to thawing permafrost and changes in the CH4 emissions from wetlands. One of the places exposed to those changes is the Abisko-Stordalen Mire in northern Sweden, where climate and vegetation studies have been conducted from the 1970s.In our study, we analyzed field-scale methane emissions measured by the eddy covariance method at Abisko-Stordalen Mire for three years (2014–2016). The site is a subarctic mire mosaic of palsas, thawing palsas, fully thawed fens, and open water bodies. A bimodal wind pattern prevalent at the site provides an ideal opportunity to measure mire patches with different permafrost statuses with one flux measurement system. The flux footprint for westerly winds is dominated by elevated palsa plateaus, while the footprint is almost equally distributed between palsas and thawing bog-like areas for easterly winds. As these patches are exposed to the same climatic conditions, we analyzed the differences in the responses of their methane emission for environmental parameters.The methane fluxes followed a similar annual cycle over the three study years, with a gentle rise during spring and a decrease during autumn and with no emission burst at either end of the ice-free season. The peak emission during the ice-free season differed significantly for the mire with two permafrost statuses: the palsa mire emitted 24 mg-CH4 m−2 d−1 and the thawing wet sector 56 mg-CH4 m−2 d−1. Factors controlling the methane emission were analyzed using generalized linear models. The main driver for methane fluxes was peat temperature for both wind sectors. Soil water content above the water table emerged as an explanatory variable for the three years for western sectors and the year 2016 in the eastern sector. Water table level showed a significant correlation with methane emission for the year 2016 as well. Gross primary production, however, did not show a significant correlation with methane emissions. Annual methane emissions were estimated based on four different gap-filing methods. The different methods generally resulted in very similar annual emissions. The mean annual emission based on all models was 4.2 ± 0.4 g-CH4 m−2 a−1 for western sector and 7.3 ± 0.7 g-CH4 m−2 a−1 for the eastern sector. The average annual emissions, derived from this data and a footprint climatology, were 3.6 ± 0.7 g-CH4 m−2 a−1 and 11 ± 2 g-CH4 m−2 a−1 for the palsa and thawing surfaces, respectively. Winter fluxes were relatively high, contributing 27–45 % to the annual emissions.

The high-resolution Sentinel-2 data potentially enable the estimation of gross primary productivity (GPP) at finer spatial resolution by better capturing the spatial variation in a heterogeneous landscapes. This study investigates the potential of 10 m resolution reflectance from the Sentinel-2 Multispectral Instrument to improve the accuracy of GPP estimation across Nordic vegetation types, compared with the 250 m and 500 m resolution reflectance from the Moderate Resolution Imaging Spectroradiometer (MODIS). We applied linear regression models with inputs of two-band enhanced vegetation index (EVI2) derived from Sentinel-2 and MODIS reflectance, respectively, together with various environmental drivers to estimate daily GPP at eight Nordic eddy covariance (EC) flux tower sites. Compared with the GPP from EC measurements, the accuracies of modelled GPP were generally high (R2 = 0.84 for Sentinel-2; R2 = 0.83 for MODIS), and the differences between Sentinel-2 and MODIS were minimal. This demonstrates the general consistency in GPP estimates based on the two satellite sensor systems at the Nordic regional scale. On the other hand, the model accuracy did not improve by using the higher spatial-resolution Sentinel-2 data. More analyses of different model formulations, more tests of remotely sensed indices and biophysical parameters, and analyses across a wider range of geographical locations and times will be required to achieve improved GPP estimations from Sentinel-2 satellite data.

The Arctic is exposed to even faster temperature changes than most other areas on Earth. Constantly increasing temperature will lead to thawing permafrost and changes in the methane (CH4) emissions from wetlands. One of the places exposed to those changes is the Abisko–Stordalen Mire in northern Sweden, where climate and vegetation studies have been conducted since the 1970s. In our study, we analyzed field-scale methane emissions measured by the eddy covariance method at Abisko–Stordalen Mire for 3 years (2014–2016). The site is a subarctic mire mosaic of palsas, thawing palsas, fully thawed fens, and open water bodies. A bimodal wind pattern prevalent at the site provides an ideal opportunity to measure mire patches with different permafrost status with one flux measurement system. The flux footprint for westerly winds was dominated by elevated palsa plateaus, while the footprint was almost equally distributed between palsas and thawing bog-like areas for easterly winds. As these patches are exposed to the same climatic and weather conditions, we analyzed the differences in the responses of their methane emission for environmental parameters. The methane fluxes followed a similar annual cycle over the 3 study years, with a gentle rise during spring and a decrease during autumn, without emission bursts at either end of the ice-free season. The peak emission during the ice-free season differed significantly for the two mire areas with different permafrost status: the palsa mire emitted 19 mg-C m−2 d−1 and the thawing wet sector 40 mg-C m−2 d−1. Factors controlling the methane emission were analyzed using generalized linear models. The main driver for methane fluxes was peat temperature for both wind sectors. Soil water content above the water table emerged as an explanatory variable for the 3 years for western sectors and the year 2016 in the eastern sector. The water table level showed a significant correlation with methane emission for the year 2016 as well. Gross primary production, however, did not show a significant correlation with methane emissions. Annual methane emissions were estimated based on four different gap-filing methods. The different methods generally resulted in very similar annual emissions. The mean annual emission based on all models was 3.1 ± 0.3 g-C m−2 a−1 for the western sector and 5.5 ± 0.5 g-C m−2 a−1 for the eastern sector. The average annual emissions, derived from these data and a footprint climatology, were 2.7 ± 0.5 and 8.2 ± 1.5 g-C m−2 a−1 for the palsa and thawing surfaces, respectively. Winter fluxes were relatively high, contributing 27 %–45 % to the annual emissions.

The Arctic tundra plays an important role in the carbon cycle as it stores 50% of global soil organic carbon reservoirs. The processes (fluxes) regulating these stocks are predicted to change due to direct and indirect effects of climate change. Understanding the current and future carbon balance calls for a summary of the level of knowledge regarding chamber-derived carbon dioxide (CO2) flux studies. Here, we describe progress from recently (2000-2016) published studies of growing-season CO2 flux chamber measurements, namely GPP (gross primary production), ER (ecosystem respiration), and NEE (net ecosystem exchange), in the tundra region. We review the study areas and designs along with the explanatory environmental drivers used. Most of the studies were conducted in Alaska and Fennoscandia, and we stress the need for measuring fluxes in other tundra regions, particularly in more extreme climatic, productivity, and soil conditions. Soil respiration and other greenhouse gas measurements were seldom included in the studies. Although most of the environmental drivers of CO2 fluxes have been relatively well investigated (such as the effect of vegetation type and soil microclimate on fluxes), soil nutrients, other greenhouse gases and disturbance regimes require more research as they might define the future carbon balance. Particular attention should be paid to the effects of shrubification, geomorphology, and other disturbance effects such as fire events, and disease and herbivore outbreaks. An improved conceptual framework and understanding of underlying processes of biosphere-atmosphere CO2 exchange will provide more information on carbon cycling in the tundra.

Supplemental Material, SupplementaryMaterial_Virkkalaetal for The current state of CO 2 flux chamber studies in the Arctic tundra: A review by Anna-Maria Virkkala, Tarmo Virtanen, Aleksi Lehtonen, Janne Rinne, Miska Luoto in Progress in Physical Geography: Earth and Environment

Vapaa-ajan asunnot ovat merkittävä osa suomalaisten vapaa-aikaa ja suomalaista maaseutua. Meillä on tilastojen mukaan noin 499 000 vapaa-ajan asuntoa mutta niiden määrä on todennäköisesti vieläkin suurempi. Lisäksi yli puolella suomalaisista on käytettävissään vapaa-ajan asunto. Tässä raportissa tarkastellaan suomalaista vapaa-ajan asumista niiden käyttäjien ja kuntien viranhaltijoiden näkökulmasta. Raportti esittelee kahden, vuonna 2012 toteutetun väestöotantaan perustuvan ja vuonna 2014 kuntien kehittämisestä ja maankäytön suunnittelusta vastaaville viranhaltijoille suunnatun, kyselyn tuloksia. Väestökyselyssä selvitettiin vapaa-ajan asuntojen käyttäjien asunnon hankintaa, sijaintia, varustetasoa, käyttöaikoja, paikallisyhteisöön liittyviä taloudellisia ja sosiaalisia suhteita ja elinympäristöjen laadussa havaittuja muutoksia. Kyselyn tulokset mahdollistavat vapaa-ajan asumisen tarkastelun paitsi niiden omistajien myös muiden käyttäjien osalta. Lisäksi kyselyssä on huomioitu se, että merkittävällä osalla suomalaisia on käytössään useampi kuin yksi vapaa-ajan asuntoa. Toisessa kyselyssä kartoitettiin kuntien edustajien näkemyksiä vapaa-ajan asumisen vaikutuksista alueen ympäristöön ja yhteisöön, merkityksestä paikallisessa kehittämisessä ja huomioimisesta osana kuntien maankäytön suunnittelua. Tulokset osoittavat, että vaikka vapaa-ajan asumisen katsotaan erityisesti syrjäalueilla tuovan taloudellisia hyötyjä alueelle, sitä ei pidetä kuntien ensisijaisena kehittämistavoitteena.

Tässä raportissa esitellään Sivuvaikutukset hallintaan: monitieteisen tiedon hyödyntäminen ympäristönsuojelussa -hankkeen tuloksia. Raportin päätarkoituksena on hahmottaa keinoja, joiden avulla viestintää ja vuorovaikutusta voidaan hyödyntää nykyistä tehokkaammin ympäristönsuojelun haitallisten sivuvaikutusten ehkäisyssä ja hyödyllisten edistämisessä. Aluksi esitellään vaikutuksen käsitettä sekä avataan arvioinnin ja tiedeviestinnän suhdetta. Seuraavaksi esitellään viestinnän ja vuorovaikutuksen kehittämisen kannalta oleellisimmat tulokset verkkokyselystä, jossa selvitettiin kansalaisten näkemyksiä ympäristösääntelystä. Lopuksi kootaan yhteen suosituksia viestinnän ja vuorovaikutuksen käytäntöjen kehittämiseksi.

Luonnonvara- ja luonnonsuojelupolitiikkaa on perinteisesti kehitetty toisistaan erillään, mutta kestävän kehityksen politiikan ja vuonna 2005 laaditun YK:n Vuosituhannen ekosysteemiarvion myötä on kiinnitetty aiempaa enemmän huomiota toimivien monimuotoisten ekosysteemien välttämättömyyteen ja ekosysteemien tuottamiin hyötyihin. Ihmisen riippuvuus ekosysteemien tuottamasta ruuasta, raaka-aineista, veden ja ravinteiden pidätyksestä, pienilmaston säätelystä ja virkistyksestä on tunnistettu tutkimuksessa sekä yhä enemmän myös politiikassa ja käytännön päätöksenteossa. Ekosysteemipalvelutarkastelujen tavoitteena on tuoda yhteen tieto ekosysteemien toiminnoista, tuki- ja säätelypalveluista, tuotantopalveluista, kulttuuripalveluista sekä luonnon monimuotoisuudesta, jotta palveluiden keskinäistä riippuvuutta voitaisiin arvioida ja kestävää käyttöä hallita. Ekosysteemipalveluita tarkastellaan ja ohjataan kuitenkin vielä varsin hajanaisesti, eikä uutta lähestymistapaa sovellettaessa aina osata hyödyntää jo olemassa olevia tieto- ja hallintajärjestelmiä. Tämä raportti kokoaa yhteen kansainvälisen tutkimuksen ekosysteemipalvelu- lähestymistapoja ja käytännön esimerkkejä siitä, miten erilaiset suomalaiset luonnonvarojen ja maankäytön ohjaus- ja hallinta- järjestelmät käsittelevät ekosysteemipalveluita. Raportin tarkoituksena on tuoda ajankohtainen sovellettava tietämys suomalaisten luonon- varojen, maankäytön ja luonnonsuojelun päätöksentekijöiden ja asiantuntijoiden käyttöön. Raportin ensimmäisessä osassa tunnistetaan vakiintuneet tarkastelutavat ja nostetaan esiin sellaiset menetelmät, joiden soveltaminen on vasta alkutekijöissään. Kirjallisuuteen pohjaava katsaus esittelee ekosysteemipalveluiden tarkasteluja yhteiskunnan toiminnoissa ja hallinnan kohteena, mallinnuksella, paikkatieto- tarkasteluilla ja maankäytön suunnittelussa, taloudellisella arvottamisella ja päätöksenteon tuessa. Raportin toisessa osassa havainnollistetaan ekosysteemipalveluiden sisällyttämistä päätöksentekoon ja luonnonvarojen hallintaan suomalaisten esimerkkien avulla. Luonnonvara-alan strategisten ohjelmien tarkastelu, pohjoiskarjalaisen suoalueen ekosysteemipalveluiden vertailu, Lounais-Suomen metsäluonnon monimuotoisuuden turvaamisen ekosysteemipalveluvaikutukset sekä ekosysteemipalvelujen huomioon ottaminen Helsingin Östersundomin ja Lahden Kytölän aluesuunnittelu- prosessissa havainnollistavat päätöksenteon ja hallinnan keskeisiä kysymyksiä. Suomalaiset tarkastelut osoittavat, miten ekosysteemipalveluita muuttavaa päätöksentekoa voidaan tukea tunnistamalla, arvottamalla ja vertailemalla ekosysteemien tuottamia hyötyjä sekä käyttämällä indikaattoreita, paikkatietoanalyyseja ja niiden perusteella tuotettuja karttoja. Aineistojen ja tarkastelutapojen yhdistäminen vaatii teknistä osaamista ja voimavaroja sekä sektori- ja luonnonvarakohtaisten tiedonhallintajärjestelmien yleistämistä. Uusia tarkastelumenetelmiä tulee kehittää sekä olemassa olevien järjestelmien pohjalta että tarvittaessa kehittämällä uusia yhdentäviä menetelmiä. Samalla, kun osamalleja ja sektorikohtaisiin inventointi- ja seuranta-aineistoihin pohjautuvia tarkasteluja syvennetään ja hienosäädetään, joudutaan ekosysteemi- ja sektorirajat ylittävissä tarkasteluissa tyytymään todennäköisesti totuttua karkeampaan tietoon. Kuitenkin esimerkiksi paikkatietotarkastelut osoittavat yhdentämisen tuoman lisäarvon konkreettisesti. Vuoropuhelu eri mallien tuottajien ja tarkasteluja hyödyntävien päätöksentekijöiden ja osallisten välillä on tässä välttämätöntä.

Long-term, continuous observations are needed for Earth system investigations and evaluation of simulations. The atmospheric and ecological communities have independently established field sites that have been running for many decades and are integrated into global networks. In the past decade, the importance of long-term observational networks focused on land ecosystem-atmosphere exchange, and the processes controlling land-atmosphere coupling, had been increasingly recognized and has led to the building of a global network of water, carbon and energy flux sites. This is an important step but further enhancements are necessary in order to quantify all of the land-atmosphere processes that need to be included in Earth system models. This paper describes the current land ecosystem-atmosphere measurement capabilities and presents the status and needs for global observational networks.

We used a monoterpene volume mixing ratio dataset measured from 12 June 2006 to 24 September 2007 and from 1 June 2008 to 3 March 2009 at the SMEAR II station to quantify the magnitude of anthropogenic monoterpene emissions aside from biogenic origins, to examine the anthropogenic sources, and to look at other associated pollutants. We discuss the relations between increased monoterpene mixing ratios and particle concentrations. We also characterize chemical properties of aerosol particles during two monoterpene pollution episodes in case studies. Out of 580 days analyzed, anthropogenic monoterpene pollution episodes were found on 341 (58.8%) days. The average monoterpene mixing ratio increased from 0.19 to 0.26 ppbv due to the presence of anthropogenic monoterpenes, which is equal to an increase of 36.8%. The observed anthropogenic monoterpenes were mostly from the Korkeakoski sawmill. Other gas pollutants might occasionally be emitted during the episodes, but did not show clear association with anthropogenic monoterpenes. Aerosol particle concentrations substantially increased during episodes, and monoterpene mixing ratios showed strong connections with Aitken mode particles both in number and volume concentrations. Particles associated with monoterpene episodes reached a CCN (cloud concentration nucleus) size. The chemical characterizations of aerosol particles in case studies show that the increase in aerosol particle mass was mainly from secondary organic aerosol.

Commercially available fast-response analysers for methane (CH4) and nitrous oxide (N2O) have recently become more sensitive, more robust and easier to operate. This has made their application for long-term flux measurements with the eddycovariance method more feasible. Unlike for carbon dioxide (CO2) and water vapour (H2O), there have so far been no guidelines on how to optimise and standardise the measurements. This paper reviews the state-of-the-art of the various steps of the measurements and discusses aspects such as instrument selection, setup and maintenance, data processing as well as the additional measurements needed to aid interpretation and gap-filling. It presents the methodological protocol for eddy covariance measurements of CH4 and N2O fluxes as agreed for the ecosystem station network of the pan-European Research Infrastructure Integrated Carbon Observation System and provides a first international standard that is suggested to be adopted more widely. Fluxes can be episodic and the processes controlling the fluxes are complex, preventing simple mechanistic gap-filling strategies. Fluxes are often near or below the detection limit, requiring additional care during data processing. The protocol sets out the best practice for these conditions to avoid biasing the results and long-term budgets. It summarises the current approach to gap-filling., International Agrophysics, 32 (4), ISSN:0236-8722, ISSN:2300-8725

Natural wetlands constitute the largest and most uncertain source of methane (CH₄) to the atmosphere and a large fraction of them are found in the northern latitudes. These emissions are typically estimated using process (“bottom-up”) or inversion (“top-down”) models. However, estimates from these two types of models are not independent of each other since the top-down estimates usually rely on the a priori estimation of these emissions obtained with process models. Hence, independent spatially explicit validation data are needed. Here we utilize a random forest (RF) machine-learning technique to upscale CH₄ eddy covariance flux measurements from 25 sites to estimate CH₄ wetland emissions from the northern latitudes (north of 45°N). Eddy covariance data from 2005 to 2016 are used for model development. The model is then used to predict emissions during 2013 and 2014. The predictive performance of the RF model is evaluated using a leave-one-site-out cross-validation scheme. The performance (Nash–Sutcliffe model efficiency=0.47) is comparable to previous studies upscaling net ecosystem exchange of carbon dioxide and studies comparing process model output against site-level CH₄ emission data. The global distribution of wetlands is one major source of uncertainty for upscaling CH₄. Thus,three wetland distribution maps are utilized in the upscaling. Depending on the wetland distribution map, the annual emissions for the northern wetlands yield 32 (22.3–41.2, 95 % confidence interval calculated from a RF model ensemble), 31 (21.4–39.9) or 38 (25.9–49.5) Tg(CH₄) yr⁻¹ . To further evaluate the uncertainties of the upscaled CH₄ flux data products we also compared them against output from two process models (LPX-Bernand WetCHARTs), and methodological issues related to CH₄ flux upscaling are discussed. The monthly upscaled CH₄ flux data products are available at https://doi.org/10.5281/zenodo.2560163 (Peltola et al., 2019).

Land-use changes account for three-quarters of Africa's anthropogenic greenhouse gas (GHG) emissions, yet little is known about these emissions from a wide variety of land uses, especially from the savanna in Sub-Saharan Africa. To address this gap, I conducted four studies (2018 - 2021) to quantify soil GHG emissions from dominant land use types (LUTs) in the Taita Taveta county, southern Kenya. Three studies were carried out in the lowland under savanna grassland (private conservation and community grazing), bushland, maize cropland (Zea mays L.), and sisal plantation. The fourth study was in the highlands under indigenous forest, pine and eucalyptus plantations, woodland, and maize cropland. Each study covered a whole year. Soil GHG concentrations were measured with static GHG chambers and analysed by gas chromatography over eight one-week and weekly campaigns. Environmental factors including soil temperature, volumetric soil moisture content, vegetation, soil physicochemical characteristics and grazing intensity were evaluated. Daily CO2 emissions varied between 5 – 360 mg C m-2 h-1 and differed between sites. In the lowland, grassland under conservation land had the highest CO2 emissions, while cropland and bushland had the lowest. In the highlands, the pine plantation and indigenous forest emitted higher CO2 than eucalyptus and woodland, while cropland emitted the least. Overall, soil organic carbon accounted for 50% variation in CO2 emissions between the LUTs, while grazing accounted for 60% variation between grassland under conservation and the community grazing. In the sisal plantation, the oldest and youngest stands emitted higher CO2 than mature stands, which is consistent with root respiration since soil organic carbon did not differ between stands. During each study year, CO2 emissions were highest in the wet than in the dry season due to the higher soil moisture and vegetation cover. In the lowland, soil moisture alone explained 20 – 70% seasonal variation in CO2 emissions, while vegetation (based on EVI and NDVI; proxies of vegetation status) explained 18 – 82%. The combined influence of soil moisture and vegetation dynamics proved to be a greater control accounting for 75 – 96% of seasonal variation in CO2 emissions. The indigenous forest and pine plantation were affected by soil temperature rather than moisture, but the relationship was very weak (< 20%). In the lowland, soil N2O (-7.7 – 17 µg N m- 2 h-1) and CH4 (-0.4 – 1.9 mg C m-2 h-1) emissions were very low throughout each study period. Most CH4 values were below the limit of detection (LOD; ±0.03 mg C m-2 h-1) and the ones above were sinks rather than sources, and they did not differ between seasons or sites. N2O emissions were highest in cropland and lowest in bushland but did not vary with season. In the maize cropland, manure application was very low and had no effect on N2O emissions. Due to low soil carbon, nitrogen, and moisture content at all LUTs, N2O and CH4 emissions were of minor significance. Among the assessed LUTs, soil carbon content, moisture, and vegetation characteristics were key drivers for soil GHG emissions. The findings of this study address a significant gap in the spatial and temporal variability of soil GHG emissions in Sub-Saharan Africa, which can be used to improve current estimates, thereby improving climate change mitigation measures when identifying and quantifying national contributions. In Africa, land-use changes account for three-quarters of anthropogenic greenhouse gas (GHG: carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4)) emissions. However, few studies have measured these emissions, especially in Sub-Saharan Africa's savanna, where land use changes are accelerating due to population growth. I conducted four studies to quantify soil GHG emissions from dominant land use types (LUTs) in southern Kenya's Taita Taveta county under varying management. Three studies were carried out in the lowland under savanna grassland (private conservation lands, community grazing lands), bushland, maize cropland (Zea mays L.), and sisal plantation, while the fourth in the highlands under indigenous forest, pine and eucalyptus plantations, and woodland, and adjacent maize cropland. Each study covered the whole year. Soil GHG concentrations were measured with static GHG chambers and analysed by gas chromatography. Environmental factors including soil temperature, volumetric soil moisture content, vegetation, soil physicochemical characteristics and grazing intensity were evaluated. Overall, conservation land, which is privately managed, had the highest CO2 emissions in the lowland due to dense grass cover, while cropland and bushland had the lowest. In the highlands, the pine plantation and indigenous forest with higher soil organic carbon emitted higher CO2 than eucalyptus and woodland, while cropland emitted the lowest. Soil organic carbon explained 50% of the variation in CO2 emissions between the studied LUTs, while grazing accounted for 60% difference between grassland under conservation and community grazing. In sisal plantations, the effect of stand age on GHG emissions was studied. It was found that old and young sisal stands emitted more CO2 than mature stands due to higher root respiration which increases with stand age. Harvesting and weeding interfered with root respiration in the mature stands. CO2 emissions were greater in the wet season than in the dry season due to higher soil moisture and vegetation cover. In the lowland, soil moisture explained 20 - 70% of the seasonal variation in CO2 emissions, while vegetation cover explained 18 - 82%. Combined soil moisture and vegetation dynamics accounted for 75-96% of the variation in seasonal CO2 emissions. Indigenous forests and pine plantations were affected by soil temperature more than moisture, but this relationship was very weak (< 20%), probably due to the narrow seasonal variations in soil temperature. N2O and CH4 were very low throughout each study period in the lowland. For CH4, most values were below the limit of detection, and the ones above were sinks rather than sources. Seasons and sites did not affect CH4 values. N2O emissions were highest in cropland and lowest in bushland, but they did not vary by season. Manure application in the maize cropland was very low and had no impact on N2O emissions. Overall, N2O and CH4 emissions were of minor significance at all sites due to the low soil carbon, nitrogen, and moisture conditions. In this way, this study fills a critically important gap in our understanding of soil GHG emissions in sub-Saharan Africa and contributes to better estimates of baseline GHG emissions in Africa, both of which are crucial for reducing uncertainties in global GHG budgets and for informing policymakers when discussing low-emission development strategies.

Volatile organic compounds (VOC) are emitted into the atmosphere from both biogenic and anthropogenic sources. Some VOCs act as aerosol precursor compounds in the atmosphere, and thus, affect Earth's radiative budget and the global climate. In this thesis VOC exchange between the surface and the atmosphere was studied in an ecosystem scale using micrometeorological flux measurement techniques combined with proton transfer reaction mass spectrometry for VOC concentration measurements. The measurements were obtained above three different environments: a Scots pine dominated boreal forest, a Mediterranean oak-hornbeam dominated forest, and an urban area. The main results were the following: i) The direct flux measurement technique, disjunct eddy covariance method, was found to be problematic in low-flux conditions, thus, the indirect surface layer profile method can be recommended for flux measurements in these conditions. Conversely, the eddy covariance method with a time-of-flight mass analyser was found to be a powerful tool for VOC flux measurements. ii) The total VOC flux in the boreal ecosystem was dominated by monoterpenes through the whole year, and also oxygenated VOCs made rather a large contribution. Monoterpene emissions depended on both temperature and light. On the other hand, isoprene was the dominant flux compound above the oak-hornbeam forest, while other compounds played only minor roles compared with the isoprene flux. The OVOC exchange was found to be bi-directional, i.e. many OVOCs, especially methanol, had also significant deposition to the surface. A semi-empirical algorithm was developed to determine the total exchange of methanol. iii) The VOC emissions from anthropogenic sources were significant and they could be determined with the disjunct eddy covariance method. The emission dynamics of VOCs was more complicated compared with the forest environments. However, in urban areas traffic was the most important source for many VOCs whereas isoprene originated mostly from urban vegetation. The methods applied in this study can be used in multiple ecosystems and the thesis provides some recommendations for selecting the most feasible and reliable methods. The results of the thesis, such as determined emission potentials, are also adaptable for modelling purposes. Keywords: VOC, flux, emission, deposition, PTR-MS, boreal forest, broadleaf forest, urban landscape Haihtuvat orgaaniset yhdisteet (VOC) ovat peräisin sekä luonnollisista että ihmisen toiminnasta aiheutuvista lähteistä. Eräät näistä yhdisteistä vaikuttavat pienhiukkasten kasvuun, vaikuttaen samalla maapallon säteilytasapainoon ja sitä kautta ilmastoon. Tässä väitöskirjassa tutkittiin näiden orgaanisten yhdisteiden vaihtoa maan ja ilmakehän välillä käyttäen mikrometeorologisia vuonmittaustekniikoita. Mittaukset tehtiin pohjoisen mäntymetsän, välimerellisen tammi-valkopyökkimetsän sekä esikaupunkialueen yläpuolella käyttäen protoninsiirtoreaktiomassaspektrometriaa (PTR-MS). Tutkimuksen pääasialliset tulokset olivat seuraavat: i) Suora vuonmittaustekniikka, ajoittaisen näytteenoton kovarianssimenetelmä, todettiin monilta osin ongelmalliseksi, kun vuot olivat lähellä havaintorajaa. Tämän vuoksi epäsuora profiilimenetelmä on monissa olosuhteissa soveliaampi vuonmittaustekniikka. Toisaalta lentoaikamassaspektrometri yhdistettynä kovarianssimenetelmään todettiin erinomaiseksi työkaluksi haihtuvien orgaanisten yhdisteiden vuomittauksiin. ii) Monoterpeenit olivat merkittävin VOC-ryhmä mäntymetsän yläpuolella kaikkina vuodenaikoina. Nämä monoterpeenipäästöt riippuivat lämpötilan lisäksi valosta. Tammi-valkopyökkimetsän monoterpeenipäästöt olivat toisaalta suhteellisen pieniä verrattuna isopreenipäästöihin, jotka olivat ylivoimaisesti merkittävimpiä verrattuna mihin tahansa muuhun VOC:hen. Hapettuneiden VOC:den vaihto oli kaksisuuntaista. Merkittävin laskeuma havaittiin metanolille, jonka kokonaisvaihtoa maan ja ilmakehän välillä kehitettiin kuvaamaan puolikokeellinen algoritmi. iii) VOC-päästöt ihmisperäisistä lähteistä olivat merkittäviä ja päästöjen taso oli mahdollista määrittää ajoittaisen näytteenoton kovarianssimentelmällä. Päästöjen dynamiikan todettiin olevan kaupunkialueilla huomattavasti monimutkaisempaa verrattuna em. metsiin. Tästä huolimatta liikenne arvioitiin tärkeimmäksi lähteeksi monille orgaanisille yhdisteille, mutta myös kaupunkikasvillisuudella oli suuri vaikutus esimerkiksi isopreenipäästöihin. Tutkimuksessa sovellettuja tekniikoita voidaan käyttää erilaisten ekosysteemien VOC-päästöjen tutkimiseen, ja lisäksi väitöskirjassa annetaan joitain suosituksia parhaan vuomittaustekniikan valitsemiseksi. Väitöskirjan tulokset, esimerkiksi päästöpotentiaalit, ovat myös sovellettavissa mallinnustarkoituksiin. Avainsanat: VOC, vuo, päästö, laskeuma, PTR-MS, havumetsä, lehtimetsä, kaupunkialue

Vast amount of volatile organic compounds (VOCs) are emitted into the atmosphere from various natural and manmade sources. VOCs have an important role in the atmospheric chemistry. They participate in ozone production in the planetary boundary layer and affect the oxidation capacity of the atmosphere. VOCs also contribute to the formation and growth processes of atmospheric aerosol particles, which, once large enough, can act as a cloud condensation nuclei (CCN) and influence the climate by altering the properties of clouds. Globally, VOC emissions from forest vegetation are dominating over the other sources. The circumpolar boreal forests cover more than 35% of the Earth s total forested area, making it one of the biggest biomes on planet. This thesis focuses on the biogenic VOCs in the boreal forests with regard to their shoot scale emissions to their role in the atmosphere. First, the VOC emissions of two different Larix species, L. cajanderi and L. sibirica, were measured and reported quantitatively for the first time. Larix species are the predominant trees in large parts of the Siberian forests, where the climate is too harsh for other tree species to grow. The emissions of both examined Larix species were dominated by monoterpenes similarly to other tree species with comparable emission potentials. Second, a protocol for proton transfer reaction mass spectrometer (PTR-MS) was developed for calibration and data processing of long-term and stand-alone VOC measurements. The reliability of this protocol was tested by comparing simultaneous VOC measurements of two PTR-MS and two gas chromatograph mass spectrometers (GC-MS). The detection of five compounds was analyzed in depth and strengths and weaknesses of the measurements were highlighted. Third, the increase in biogenic VOC and CCN concentrations was investigated in connection with the global warming. This was done by analyzing long-term data of concentrations and compositions of aerosol particles and their biogenic precursor VOCs in different environments. A negative aerosol-climate feedback, driven by the increase of BVOC emissions due to climate warming, was hypothesized and found. Maapallon ilmakehään haihtuu huomattava määrä erilaisia haihtuvia orgaanisia yhdisteitä (VOC, volatile organic compound) luonnollisista lähteistä ja ihmisen toiminnan seurauksena. VOC-yhdisteillä on merkittävä rooli ilmakehän kemiassa, sillä ne osallistuvat otsonin tuotantoon rajakerroksessa ja vaikuttavat ilmakehän hapetuskykyyn. Lisäksi VOC-yhdisteet osallistuvat ilmakehän aerosolihiukkasten muodostus- ja kasvuprosesseihin. Hiukkasten kasvaessa riittävän suuriksi, ne voivat toimia tiivistymisytiminä (CCN, cloud condensation nucleai), joiden ympärille tiivistyvä vesihöyry muodostaa pilviä. Tiivistymisytimien lukumäärä vaikuttaa pilvien ominaisuuksiin ja sitä kautta maapallon ilmastoon. Maailmanlaajuisesti tarkasteltuna suurin VOC-yhdisteiden lähde on metsien kasvillisuus, erityisesti puut. Boreaaliset havumetsät kattavat yli 35 % maapallon kokonaismetsäalasta. Tässä väitöskirjatyössä tutkittiin haihtuvien orgaanisten yhdisteiden merkitystä boreaalisella kasvillisuusvyöhykkeellä, alkaen yksittäisten puiden VOC-emissioista päätyen VOC-yhdisteiden rooliin ilmaston kannalta. Kaksi ensimmäistä osajulkaisua keskittyvät kahden eri lehtikuusilajin (Larix cajanderi ja Larix sibirica) VOC-päästöjen mittauksiin. Lehtikuusten VOC-päästöjä ei ole aiemmin mitattu kvantitatiivisesti, vaikka lehtikuuset ovat vallitseva puulaji suuressa osassa Siperian havumetsävyöhykkeellä jossa ilmasto on liian ankara muille puulajeille. Samoin kuin muiden aiemmin mitattujen havupuiden, myös lehtikuusten päästöt olivat suurimmaksi osaksi monoterpeenejä. Lehtikuusille lasketut monoterpeenien emissiopotentiaalit olivat samaa suuruusluokkaa muiden havupuiden emissiopotentiaalien kanssa. Kolmas osajulkaisu esittelee mittausprotokollan, joka kehitettiin protoninvaihtoreaktio-massaspektrometriä (PTR-MS) varten. Protokollaan sisältyvä laitteen säännöllinen kalibrointi sekä mittaustulosten konsistentti analysointi mahdollistavat jatkuvatoimiset ja pitkäkestoiset kenttämittaukset. Kehitetyn mittausprotokollan luotettavuutta testattiin neljännessä osajulkaisussa vertaamalla samaan aikaan kahdella PTR-MS:llä ja kahdella kaasukromatografi-massaspektrometrillä (GC-MS) tehtyjä kenttämittauksia. Vertailumittauksista analysoitiin perusteellisesti viiden eri yhdisteen tulokset. Eri mittalaitteiden tulosten havaittiin korreloivan melko. Joidenkin yhdisteiden tulokset korreloivat heikommin kalibrointiin liittyvien haasteiden vuoksi. Viidennessä osajulkaisussa esitettiin hypoteesi, jonka mukaan ilmaston lämpenemiseen liittyvä kasvillisuuden VOC-emissioiden kasvu ja siitä johtuva tiivistymisydinten lukumääräpitoisuuden kasvu aiheuttavat negatiivisen ilmastollisen takaisinkytkennän, eli ilmastoa viilentävän takaisinkytkennän. Hypoteesin paikkansa pitävyyttä tutkittiin analysoimalla pitkän aikavälin mittaustuloksia usealta eri mittausasemalta. Analysoidun aineiston perusteella negatiivinen takaisinkytkentä voitiin todentaa.

Volatile organic compounds (VOCs) are known to be key players in the atmospheric processes. They are emitted both from natural and non-biogenic sources. Although the biogenic sources are generally dominant compared with the anthropogenic sources in some circumstances the anthropogenic emissions can dominate e.g. in densely populated areas or during pollution plumes. VOCs are ambient trace gases including a vast group of compounds. Some of the VOCs are very reactive, participating in atmospheric transformation processes e.g. secondary organic aerosol formation and growth. Some VOCs are also known to be harmful air pollutants for humans. Thus VOCs can have direct effects on air quality and secondary effects on climate. In this thesis, the aim was to define sources of VOCs, determine influence of transport and transformation of trace gases and aerosols. VOCs were measured mainly by a real time proton transfer reaction mass spectrometer. In addition, gas and liquid chromatography were used. The measurements were conducted at the rural SMEAR II and the urban background SMEAR III sites. Concentrations of VOCs were observed to have inter-annual, seasonal and diurnal variations due to meteorological factors, photochemistry and different sources. The anthropogenic influence was dominant in winter at both sites, while the biogenic influence with enhanced photochemical reactions increased in spring. The mixing and dilution effect also increased in spring and it led to decreased levels of volume mixing ratios (VMRs) in daytime especially in short-lived compounds. The VMRs of aromatic compounds were lower in spring than in winter due to lesser sources and enhanced photochemistry at both sites. At the urban background site there were more local sources than rural site and thus more variation of the diurnal patterns; higher VMRs of VOCs were observed. At both sites long-range transport was found to be an important source for long-lived VOCs. The source areas of long-lived VOCs were studied with trajectory analysis. Eastern Europe including West Russia was found to be major source area for all studied VOCs. In addition, some of them had specific source areas of their own related e.g. to their use in the solvent industry. During measurements there were two different forest fire episodes in Eastern Europe and a one-day prescribed biomass burning experiment. VMRs of VOCs related to burning were observed to increase during these pollution plumes. Atmospheric oxidation of BVOCs (biogenic VOCs) revealed that monoterpenes and their oxidation products by ozone were limiting factors for nucleation particle growth. Study of total OH reactivity showed that there are a number of unmeasured biogenic compounds which may have effects on the local atmospheric chemical processes. Keywords: variations of VOC concentrations, source analysis, long-range transport, forest fires, atmospheric chemistry Haihtuvat orgaaniset yhdisteet (volatile organic compounds, VOC) ovat avainrooleissa ilmakehän prosessissa kuten hiukkasten ja otsonin muodostumisreaktioissa. Näitä yhdisteitä vapautuu sekä luonnollisista lähteistä että ihmisen toiminnasta. Vaikka yleensä suurin osa haihtuvista yhdisteistä on peräisin luonnollisista lähteistä, voivat ihmistoiminnasta aiheutuvat lähteet hallita päästöjä esim. tiheästi asutuilla alueilla tai metsäpaloperäisten saastesavujen kaukokulkeutumisen vuoksi. Haihtuvat orgaaniset yhdisteet ovat monikirjoinen ryhmä. Osa näistä yhdisteistä on hyvin reaktiivisia ja ne osallistuvat aerosolihiukkasten muodostumiseen ja kasvuun. Jotkut haihtuvat yhdisteet, kuten bentseeni, ovat terveydelle haitallisia. Haihtuvilla yhdisteillä voi olla siten suoria vaikutuksia ilmanlaatuun ja epäsuoria vaikutuksia ilmastoon. Työn tarkoituksena oli selvittää haihtuvien orgaanisten yhdisteiden pitoisuuksiin vaikuttavia lähdeitä sekä tutkia niiden hapetustuotteiden osallistumista hiukkasten kasvuun ja ilmakehän OH radikaalin hapetuskykyä. VOC-yhdisteitä mitattiin jatkuvatoimisesti protonin-vaihtoreaktio-massaspektrometrillä ja täydentävinä menetelminä käytettiin kaasu-ja nestekromatografiaa. Mittaukset tehtiin haja-asutusalueella sijaitsevalla SMEAR II asemalla ja SMEAR III kaupunki tausta-asemalla. Pitoisuuksilla havaittiin olevan vuosittaisia, vuodenaikaisia ja päivän sisäistä vaihtelua. Vaihtelua aiheuttivat meteorologiset tekijät, valokemia and erilaiset päästöt. Ihmistoiminnan vaikutuksen havaittiin vallitsevan pitoisuusvaihtelua talvella molemmilla mittausasemilla, ja vastaavasti luonnollisten lähteiden vaikutus voimistui keväällä. Sekoittuminen ja pitoisuuksien laimennusvaikutus voimistui keväällä, mikä madalsi päiväaikaisia pitoisuuksia lyhytikäisillä haihtuvilla yhdisteillä. Aromaattisten yhdisteiden pitoisuudet olivat matalampia keväällä molemmilla asemilla voimistuneiden valokemiallisten hajoamisreaktioiden ja vähäisempien päästöjen vuoksi. Yleisesti haihtuvien yhdisteiden pitoisuudet olivat korkeampia ja niiden vuorokausikäytöksessä oli enemmän vaihtelua kaupunkitausta-asemalla kuin haja-asutusalueella. Kaukokulkeuman havaittiin olevan tärkeä lähde pitkäikäisille haihtuville yhdisteille molemmilla asemilla. Suurin lähdealue pitkäikäisille haihtuville yhdisteille oli Itä-Eurooppa mukaan lukien Länsi-Venäjä. Lisäksi joillakin näistä yhdisteistä oli erityisiä lähdealueita liittyen niiden käyttöön esim. teollisuudessa. Mittausjakson aikana Itä-Euroopassa oli kaksi erillistä metsäpalojaksoa ja yksi suunniteltu koepoltto SMEAR II asemalla, joiden yhteydessä haihtuvien yhdisteiden pitoisuudet kohosivat. Ilmakehän kemiaa tutkittiin reaktiivisilla lyhytikäisillä haihtuvilla yhdisteillä: monoterpeeneillä, joiden havaittiin yhdessä otsonin kanssa muodostaminen hapetustuotteiden kanssa olevan yksi hiukkasten kasvua rajoittava tekijä. Ilmakehän OH radikaalin hapetuskykyä tutkittaessa havaittiin, että, kattavillakin mittauksilla havaitaan vain alle puolet reagoivista yhdisteistä. Puuttuvien yhdisteiden arvellaan vapautuvan metsistä ja näillä todennäköisesti biogeenisillä yhdisteillä voi olla vaikutusta ilmakehän kemiallisiin prosesseihin. Avainsanat: haihtuvien orgaanisten yhdisteiden pitoisuusvaihtelut, lähdeanalyysi, kaukokulkeuma, metsäpalot, ilmakemia

Volatile organic compounds (VOCs) affect atmospheric chemistry and thereafter also participate in the climate change in many ways. The long-lived greenhouse gases and tropospheric ozone are the most important radiative forcing components warming the climate, while aerosols are the most important cooling component. VOCs can have warming effects on the climate: they participate in tropospheric ozone formation and compete for oxidants with the greenhouse gases thus, for example, lengthening the atmospheric lifetime of methane. Some VOCs, on the other hand, cool the atmosphere by taking part in the formation of aerosol particles. Some VOCs, in addition, have direct health effects, such as carcinogenic benzene. VOCs are emitted into the atmosphere in various processes. Primary emissions of VOC include biogenic emissions from vegetation, biomass burning and human activities. VOCs are also produced in secondary emissions from the reactions of other organic compounds. Globally, forests are the largest source of VOC entering the atmosphere. This thesis focuses on the measurement results of emissions and concentrations of VOCs in one of the largest vegetation zones in the world, the boreal zone. An automated sampling system was designed and built for continuous VOC concentration and emission measurements with a proton transfer reaction - mass spectrometer (PTR-MS). The system measured one hour at a time in three-hourly cycles: 1) ambient volume mixing-ratios of VOCs in the Scots-pine-dominated boreal forest, 2) VOC fluxes above the canopy, and 3) VOC emissions from Scots pine shoots. In addition to the online PTR-MS measurements, we determined the composition and seasonality of the VOC emissions from a Siberian larch with adsorbent samples and GC-MS analysis. The VOC emissions from Siberian larch were reported for the fist time in the literature. The VOC emissions were 90% monoterpenes (mainly sabinene) and the rest sesquiterpenes (mainly a-farnesene). The normalized monoterpene emission potentials were highest in late summer, rising again in late autumn. The normalized sesquiterpene emission potentials were also highest in late summer, but decreased towards the autumn. The emissions of mono- and sesquiterpenes from the deciduous Siberian larch, as well as the emissions of monoterpenes measured from the evergreen Scots pine, were well described by the temperature-dependent algorithm. In the Scots-pine-dominated forest, canopy-scale emissions of monoterpenes and oxygenated VOCs (OVOCs) were of the same magnitude. Methanol and acetone were the most abundant OVOCs emitted from the forest and also in the ambient air. Annually, methanol and mixing ratios were of the order of 1 ppbv. The monoterpene and sum of isoprene 2-methyl-3-buten-2-ol (MBO) volume mixing-ratios were an order of magnitude lower. The majority of the monoterpene and methanol emissions from the Scots-pinedominated forest were explained by emissions from Scots pine shoots. The VOCs were divided into three classes based on the dynamics of the summer-time concentrations: 1) reactive compounds with local biological, anthropogenic or chemical sources (methanol, acetone, butanol and hexanal), 2) compounds whose emissions are only temperaturedependent (monoterpenes), 3) long-lived compounds (benzene, acetaldehyde). Biogenic VOC (methanol, acetone, isoprene MBO and monoterpene) volume mixing-ratios had clear diurnal patterns during summer. The ambient mixing ratios of other VOCs did not show this behaviour. During winter we did not observe systematical diurnal cycles for any of the VOCs. Different sources, removal processes and turbulent mixing explained the dynamics of the measured mixing-ratios qualitatively. However, quantitative understanding will require longterm emission measurements of the OVOCs and the use of comprehensive chemistry models. Keywords: Hydrocarbons, VOC, fluxes, volume mixing-ratio, boreal forest Haihtuvat orgaaniset yhdisteet eli VOCit vaikuttavat ilmakehän kemiaan ja sen myötä myös ilmaston muutokseen. Pitkäikäiset kasvihuonekaasut (kuten metaani) ja troposfäärin otsoni muodostavat merkittävimmän ilmastoa lämmittävän säteilypakotteen, kun taas ilmakehän aerosoli-hiukkasilla on merkittävin ilmastoa viilentävä vaikutus. Siten myös VOCeilla on ilmastoa lämmittävä vaikutus, sillä ne osallistuvat troposfäärin otsonin muodostumiseen ja lisäksi pidentävät esimerkiksi metaanin elinikää kilpailemalla ilmakehän hapettimista, joista tärkeimmät ovat OH, otsoni ja NO3. Toisaalta osa VOCeista viilentää ilmastoa osallistumalla aerosoli-hiukkasten muodostumiseen. Lisäksi osalla orgaanisista yhdisteistä, kuten syöpää aiheuttavalla bentseenillä, on suoria vaikutuksia ihmisten terveyteen. Muun muassa kasvillisuus, biomassan ja fossiilisten polttoaineiden poltto sekä ilmassa tapahtuvat kemialliset reaktiot ovat ilmakehän orgaanisten yhdisteiden lähteitä. Metsät, joista havupuut muodostavat merkittävän osan, ovat maailmanlaajuisesti ilmakehän suurin VOC-lähde. Tässä väitöskirjassa keskitytään havupuumetsän VOC-päästöjen ja ympäröivän ilman orgaanisten yhdisteiden pitoisuuksien mittaustuloksiin. Havupuumetsän orgaanisten yhdisteiden päästöt ja pitoisuudet ilmassa mitattiin protonin-vaihtoreaktio-massaspektrometrillä (PTR-MS). Suunnittelimme ja rakensimme automatisoidun näytteenottojärjestelmän, joka mittasi kolmen tunnin välein, tunnin kerrallaan 1) ilman VOC-pitoisuuksia pääosin männyistä muodostuvassa metsässä, 2) VOCien vuota lehvästön yläpuolelta ja 3) männyn edellisen kesän vuosikasvun VOC-päästöjä. Lisäksi määritimme adsorbentti-näytteillä, jotka analysoitiin laboratoriossa kaasukromatogrammi-massaspektrometrillä, siperianlehtikuusen VOC-päästöjen koostumuksen ja niiden muutokset kasvukauden aikana. Siperianlehtikuusi on yksi taiga-alueen yleisimmistä puulajeista, ja sen VOC-päästöjä ei ole julkaistu aiemmin. Mittauksemme osoittivat, että VOC-päästöt olivat lähinnä mono- (90%) ja seskviterpeenejä (9%). Vakiolämpötilaan normalisoidut monoterpeeni- ja seskviterpeenipäästöpotentiaalit olivat suurimmillaan loppukesästä. Monoterpeenien päästöpotentiaali nousi uudelleen loppusyksyllä ennen neulasten putoamista, kun taas samaan aikaan seskviterpeenien päästöpotentiaali heikkeni. Lämpötila-algoritmi kuvasi hyvin siperianlehtikuusen mono- ja seskviterpeenipäästöjä sekä männyn monoterpeenipäästöjä. Havupuumetsän lehvästön monoterpeenien ja hapettuneiden VOCien, jotka olivat pääosin metanolia ja asetonia, päästöt olivat samansuuruiset. Suurimmat VOC-ilmapitoisuudet (tyypillisesti luokkaa 1 ppb) mitattiin metanolille ja asetonille. Monoterpeenien ja isopreeni 2-metyyli-3-buteeni-2-oli (MBO) yhdistelmän pitoisuudet olivat kertaluokkaa pienemmät. Metsän monoterpeenien ja metanolin päästöistä valtaosa selittyi männyn oksien päästöillä. Jaoimme VOCit kesällä mitattujen pitoisuuksien dynamiikan mukaan kolmeen ryhmään: 1) reaktiiviset yhdisteet, joilla on paikallisia lähteitä (metanoli, asetoni, butanoli ja hexanaali), 2) yhdisteet, joiden päästöt riippuvat vain lämpötilasta (monoterpeenit) ja 3) pitkäikäiset yhdisteet (bentseeni, asetaldehydi). Metanolilla, asetonilla, isopreeni-MBOlla ja monoterpeeneillä on lähteitä luonnossa, ja niiden pitoisuuksilla oli kesäisin selkeä vuorokausivaihtelu. Muiden yhdisteiden pitoisuuksissa ei havaittu vuorokausivaihtelua. Talvella metsän VOC-pitoisuudet eivät riippuneet vuorokaudenajasta. Huomioimalla lähteet, poistoprosessit ja turbulentti sekoittuminen pitoisuuksien vaihtelu selittyi kvalitatiivisesti. Pitoisuuksien tarkempi, kvantitatiivinen, ymmärtäminen vaatii pitkäaikaisia hapettuneiden orgaanisten yhdisteiden päästöjen mittauksia mäntymetsästä sekä kattavaa kemiallista mallinnusta.

Microbial activity in soils is the main source of nitrous oxide (N2O) to the atmosphere. Nitrous oxide is a strong greenhouse gas in the troposphere and participates in ozone destructive reactions in the stratosphere. The constant increase in the atmospheric concentration, as well as uncertainties in the known sources and sinks of N2O underline the need to better understand the processes and pathways of N2O in terrestrial ecosystems. This study aimed at quantifying N2O emissions from soils in northern Europe and at investigating the processes and pathways of N2O from agricultural and forest ecosystems. Emissions were measured in forest ecosystems, agricultural soils and a landfill, using the soil gradient, chamber and eddy covariance methods. Processes responsible for N2O production, and the pathways of N2O from the soil to the atmosphere, were studied in the laboratory and in the field. These ecosystems were chosen for their potential importance to the national and global budget of N2O. Laboratory experiments with boreal agricultural soils revealed that N2O production increases drastically with soil moisture content, and that the contribution of the nitrification and denitrification processes to N2O emissions depends on soil type. Laboratory study with beech (Fagus sylvatica) seedlings demonstrated that trees can serve as conduits for N2O from the soil to the atmosphere. If this mechanism is important in forest ecosystems, the current emission estimates from forest soils may underestimate the total N2O emissions from forest ecosystems. Further field and laboratory studies are needed to evaluate the importance of this mechanism in forest ecosystems. The emissions of N2O from northern forest ecosystems and a municipal landfill were highly variable in time and space. The emissions of N2O from boreal upland forest soil were among the smallest reported in the world. Despite the low emission rates, the soil gradient method revealed a clear seasonal variation in N2O production. The organic topsoil was responsible for most of the N2O production and consumption in this forest soil. Emissions from the municipal landfill were one to two orders of magnitude higher than those from agricultural soils, which are the most important source of N2O to the atmosphere. Due to their small areal coverage, landfills only contribute minimally to national N2O emissions in Finland. The eddy covariance technique was demonstrated to be useful for measuring ecosystem-scale emissions of N2O in forest and landfill ecosystems. Overall, more measurements and integration between different measurement techniques are needed to capture the large variability in N2O emissions from natural and managed northern ecosystems. Typpioksiduuli (N2O) eli ilokaasu on voimakas kasvihuonekaasu alailmakehässä ja osallistuu otsonia tuhoaviin reaktioihin yläilmakehässä. Ihmistoiminnan ansiosta typpioksiduulin pitoisuus alailmakehässä on jatkuvasti kohonnut. Maan mikrobitoiminta on merkittävin typpioksiduulin lähde ilmakehään, mutta maaperän prosessit typpioksiduulin lähteinä ja nieluina ja typpioksiduulin kuljetusmekanismit maasta ilmakehään tunnetaan huonosti. Tämän tutkimuksen tavoitteena oli määrittää N2O-päästöjä erilaisissa pohjoisen ilmastovyöhykkeen ympäristöissä, ja tutkia typpioksiduulin tuotto- ja kuljetusprosesseja. Typpioksiduulipäästöjä mitattiin maatalous- ja metsämailla sekä kaatopaikalla. Mittauspaikoiksi valittiin sellaisia ekosysteemejä, joiden arvioitiin olevan merkittäviä typpioksiduulin päästölähteitä, mutta joista oli olemassa vain vähän aikaisempaa mittaustietoa. Laboratoriokokeissa havaittiin, että maatalousmaiden typpioksiduulin tuotto lisääntyy radikaalisti maan kosteuden kasvaessa. Maan mikrobiologisten prosessien, nitrifikaation ja denitrifikaation, osuudet typpioksiduulin tuotossa olivat riippuvaisia maalajista. Tutkimuksen toisessa laboratoriokokeessa havaittiin, että puiden taimet pystyvät kuljettamaan maaperässä tuotettua typpioksiduulia ilmakehään. Nykyiset metsäekosysteemien päästöarviot perustuvat maaperän päästöjen mittaamiseen. Mikäli merkittävä osa maassa tuotetusta typpioksiduulista kulkeutuu ilmakehään puiden kautta, nykyiset arviot metsämaiden N2O-päästöistä voivat olla aliarvio todellisista metsikkötason päästöistä. Typpioksiduulipäästöt metsämailta ja kaatopaikalta olivat hyvin vaihtelevia ajan ja mittauspaikan suhteen. Boreaalisen vyöhykkeen kangasmetsän N2O-päästöt olivat erittäin pieniä ja ajoittain metsämaa toimi typpioksiduulin nieluna. Pääosa typpioksiduulin mikrobiologisesta tuotosta ja kulutuksesta tapahtui maan orgaanisessa pintakerroksessa. Kaatopaikkojen typpioksiduulipäästöt olivat yhdestä kahteen kertaluokkaa suuremmat kuin päästöt maatalousmailta, jotka ovat merkittävin typpioksiduulin päästölähde Suomessa. Kaatopaikkojen pienen pinta-alan vuoksi niiden merkitys Suomen kokonaispäästöihin on kuitenkin pieni. Tutkimus osoitti, että N2O-päästöt erilaisista ympäristöistä vaihtelevat huomattavasti ajan ja paikan suhteen. Päästöjen suuren vaihtelun vuoksi tarvitaan lisää päästömittauksia sekä päästövertailuja eri menetelmillä, jotta typpioksiduulin virrat maasta ilmakehään voidaan arvioida tarkemmin.

Understanding the interaction between precipitation and vegetation growth in water-limited ecosystems is vital for various livelihoods that depend on water resources. Precipitation is the primary driver of vegetation growth in dry ecosystems, while fog deposition is essential for the microclimate at dry coastal ecosystems and cloud forests. The analysis of soil moisture, which incorporates the action of climate, soil, and vegetation, is the key to understanding the carbon and water relations and the interaction between precipitation and vegetation. This thesis examines the impacts of precipitation variability on carbon and water relations in African savannas and the similarities in rainfall and fog deposition. The ecosystem-scale transpiration was estimated from eddy covariance measurements based on annually fitted water use efficiency and optimality hypothesis. The soil moisture measurements were analyzed using a hierarchy of soil moisture models with precipitation, NDVI, and potential evapotranspiration (PET) variability. The statistics of fog and rainfall were analyzed using an analogy with self-organized criticality. The annual evapotranspiration (ET) was comparable to the annual precipitation at the grazed savanna grassland. While the annual precipitation was highly variable, the estimated annual transpiration was nearly constant 55 % of ET. The transpiration (T) was reduced only during the drought year due to grass dieback-regrowth and possibly due to other changes in soil surface properties that enhanced evaporation. The annual net CO2 exchange (NEE) had large variation ranging from –58 (sink) to 198 (source) gC m-2 yr-1. The annual NEE was related to the maximum of remotely sensed vegetation index (NDVI), and the annual ecosystem respiration was strongly correlated with early season rainfall amount. The analysis of measured soil moisture across savannas showed that NDVI and PET adjustments to daily maximum ET are necessary for modeling depth averaged soil moisture. The soil moisture memory timescale, a rough measure of the time it takes for a soil column to forget the initial soil moisture state, was linearly related to daily mean precipitation intensity at semi-arid savannas. Both rainfall and fog time series showed approximate power-law relations for dry period and event size distributions consistent with self-organized criticality prediction. The spectral exponents of the on-off time series of the fog and rainfall exhibited an approximate f(-0.8) scaling, but the on-off switching was not entirely independent from the amplitude intermittency in fog and rainfall. The results show the role of short and long-term variability in precipitation and its consequences for the carbon and water cycle of semi-arid savannas with significant tree cover. These findings can be used to develop minimalist water balance models to understand how vegetation state affects water resources. Sateen ja kasvien vuorovaikutuksen ymmärtäminen on tärkeää kuivissa ekosysteemeissä, joissa kasvien aktiivisuus riippuu vesivaroista. Sade määrittää ensisijaisesti kasvillisuuden kasvua kuivissa ekosysteemeissä. Sumu on myös tärkeä tekijä kuivien rannikkoekosysteemien ja pilvimetsien mikroilmastoille. Maankosteutta tutkimalla voidaan ymmärtää veden ja hiilen kiertoa, sekä sateen ja kasvillisuuden vuorovaikutusta. Tässä väitöskirjassa tarkastellaan sateen vaihtelun vaikutusta hiilen ja veden kiertoon Afrikan savanneilla, sekä sateen ja sumun samankaltaisuutta. Maankosteutta tutkittiin neljällä eri Afrikan savannilla käyttäen malleja, joissa sadanta, normalisoitu kasvillisuusindeksi (NDVI) ja potentiaalinen haihdunta (PET) otettiin asteittain huomioon. Etelä-Afrikan laidunnetulla heinäsavannilla ekosyysteemin transpiraatio arvioitiin mikrometeorologisista kovarianssimittauksista (EC-menetelmä) määrittämällä vuosittainen vedenkäytön tehokkuus ja olettamalla optimaalinen suhde hiilen ja veden diffuusiolle ilmaraoista. Sumun ja sateen mittauksia analysoitiin nojautumalla itseorganisoituvasti kriittiseen teoriaan (self organized criticality, SOC). Vuosittainen haihdunta (ET) oli saman suuruinen vuosisateen kanssa laidunnetulla heinäsavannilla. Vuosittainen sademäärä vaihteli suuresti, mutta arvioitu vuosittainen transpiraatio oli kaikkina vuosina noin 55% vuosittaisesta haihdunnasta. Transpiraatio väheni vain erityisen kuivana vuonna, jolloin heinien lakastuminen ja uudelleen kasvu sekä muut maanpinnan ominaisuuksien muutokset lisäsivät haihduntaa maaperästä. Ekosysteemi vaihteli hiilen nielusta (–58 gC m-2 yr-1) hiilen lähteeksi (198 gC m-2 yr-1). Vuosittainen nettohiilenvaihto korreloi kaukokartoitusaineistosta arvioidun maksimaalisen kasvillisuusindeksin (NDVI) kanssa, kun taas vuosittainen kokonaishengitys korreloi alkukauden sademäärän kanssa. Eri savannien maankosteusmittauksien analysointi osoitti, että NDVI ja PET muuttujien vaikutus päivän maksimaaliseen haihduntaan täytyy ottaa huomioon syvyyskeskiarvoistetun maankosteuden mallintamisessa. Maaperän kosteuden aikasarjalle laskettiin niin kutsuttu muisti, joka kuvaa keskimääräistä ajanjaksoa, jossa maankosteus poikkea alkuarvostaan. Tämä muisti korreloi lineaarisesti päiväkeskiarvoisen sateen intensiteetin kanssa kuivilla savanneilla. Sateen ja sumun aikasarjoissa havaittiin likimääräinen potenssilaki kuivien ajanjaksojen ja sadetapahtuman sademäärän jakaumissa. Tämä havainto on yhdenmukainen SOC mallin kanssa. Binäärisen sade/ei-sade ja sumu/ei-sumu aikasarjojen tehospektri noudatteli likimääräisesti f(-0.8) potenssilakia, jossa f on taajuus. Kuitenkaan binääriset aikasarjat eivät olleet täysin riippumattomia sateen ja sumun amplitudin epäsäännöllisyydestä. Väitöskirjan tulokset osoittavat sateen lyhyen ja pitkän aikavälin vaihtelun seuraukset hiilen ja veden kierrolle kuivilla savanneilla. Näitä tuloksia voidaan jatkossa käyttää minimaalisten vesitasemallien kehittämisessä ja arvioidessa kasvillisuuden vaikutusta vesivaroihin.