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Träfflista för sökning "WFRF:(Asmi Ari) "

Search: WFRF:(Asmi Ari)

  • Result 1-9 of 9
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1.
  • Paasonen, Pauli, et al. (author)
  • Warming-induced increase in aerosol number concentration likely to moderate climate change
  • 2013
  • In: Nature Geoscience. - 1752-0908. ; 6:6, s. 438-442
  • Journal article (peer-reviewed)abstract
    • Atmospheric aerosol particles influence the climate system directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei(1-4). Apart from black carbon aerosol, aerosols cause a negative radiative forcing at the top of the atmosphere and substantially mitigate the warming caused by greenhouse gases(1). In the future, tightening of controls on anthropogenic aerosol and precursor vapour emissions to achieve higher air quality may weaken this beneficial effect(5-)7. Natural aerosols, too, might affect future warming(2,3,8,9). Here we analyse long-term observations of concentrations and compositions of aerosol particles and their biogenic precursor vapours in continental mid-and high-latitude environments. We use measurements of particle number size distribution together with boundary layer heights derived from reanalysis data to show that the boundary layer burden of cloud condensation nuclei increases exponentially with temperature. Our results confirm a negative feedback mechanism between the continental biosphere, aerosols and climate: aerosol cooling effects are strengthened by rising biogenic organic vapour emissions in response to warming, which in turn enhance condensation on particles and their growth to the size of cloud condensation nuclei. This natural growth mechanism produces roughly 50% of particles at the size of cloud condensation nuclei across Europe. We conclude that biosphere-atmosphere interactions are crucial for aerosol climate effects and can significantly influence the effects of anthropogenic aerosol emission controls, both on climate and air quality.
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2.
  • Adamaki, Angeliki, et al. (author)
  • ENVRI-FAIR Project brief on implementation of Open Science and EOSC targets
  • 2021
  • Other publication (other academic/artistic)abstract
    • In the ENVRI-FAIR project brief on implementation of Open Science and EOSC targets the current achievements and planned activities in ENVRI-FAIR are summarised with regard to a) Integration with the EOSC infrastructure b) FAIR principles implementation and repositories c) Technical, semantic, legal and organisational interoperability d) Stewardship of data and e) Cross-cluster collaboration activities and achievements.
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3.
  • Lappalainen, Hanna K., et al. (author)
  • Pan-Eurasian Experiment (PEEX) : towards a holistic understanding of the feedbacks and interactions in the land-atmosphere-ocean-society continuum in the northern Eurasian region
  • 2016
  • In: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 16:22, s. 14421-14461
  • Journal article (peer-reviewed)abstract
    • The northern Eurasian regions and Arctic Ocean will very likely undergo substantial changes during the next decades. The Arctic-boreal natural environments play a crucial role in the global climate via albedo change, carbon sources and sinks as well as atmospheric aerosol production from biogenic volatile organic compounds. Furthermore, it is expected that global trade activities, demographic movement, and use of natural resources will be increasing in the Arctic regions. There is a need for a novel research approach, which not only identifies and tackles the relevant multi-disciplinary research questions, but also is able to make a holistic system analysis of the expected feedbacks. In this paper, we introduce the research agenda of the Pan-Eurasian Experiment (PEEX), a multi-scale, multi-disciplinary and international program started in 2012 (https://www.atm.helsinki.fi/peex/). PEEX sets a research approach by which large-scale research topics are investigated from a system perspective and which aims to fill the key gaps in our understanding of the feedbacks and interactions between the land-atmosphereaquatic-society continuum in the northern Eurasian region. We introduce here the state of the art for the key topics in the PEEX research agenda and present the future prospects of the research, which we see relevant in this context.
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4.
  • Nieminen, Tuomo, et al. (author)
  • Global analysis of continental boundary layer new particle formation based on long-term measurements
  • 2018
  • In: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 18:19, s. 14737-14756
  • Journal article (peer-reviewed)abstract
    • Atmospheric new particle formation (NPF) is an important phenomenon in terms of global particle number concentrations. Here we investigated the frequency of NPF, formation rates of 10 nm particles, and growth rates in the size range of 10-25 nm using at least 1 year of aerosol number size-distribution observations at 36 different locations around the world. The majority of these measurement sites are in the Northern Hemisphere. We found that the NPF frequency has a strong seasonal variability. At the measurement sites analyzed in this study, NPF occurs most frequently in March-May (on about 30 % of the days) and least frequently in December-February (about 10 % of the days). The median formation rate of 10 nm particles varies by about 3 orders of magnitude (0.01-10 cm(-3) s(-1)) and the growth rate by about an order of magnitude (1-10 nm h(-1)). The smallest values of both formation and growth rates were observed at polar sites and the largest ones in urban environments or anthropogenically influenced rural sites. The correlation between the NPF event frequency and the particle formation and growth rate was at best moderate among the different measurement sites, as well as among the sites belonging to a certain environmental regime. For a better understanding of atmospheric NPF and its regional importance, we would need more observational data from different urban areas in practically all parts of the world, from additional remote and rural locations in North America, Asia, and most of the Southern Hemisphere (especially Australia), from polar areas, and from at least a few locations over the oceans.
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5.
  • Patoulias, David, et al. (author)
  • Simulation of the size-composition distribution of atmospheric nanoparticles over Europe
  • 2018
  • In: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 18:18, s. 13639-13654
  • Journal article (peer-reviewed)abstract
    • PMCAMx-UF, a three-dimensional chemical transport model focusing on the simulation of the ultrafine particle size distribution and composition has been extended with the addition of the volatility basis set (VBS) approach for the simulation of organic aerosol (OA). The model was applied in Europe to quantify the effect of secondary semi-volatile organic vapors on particle number concentrations. The model predictions were evaluated against field observations collected during the PEGASOS 2012 campaign. The measurements included both ground and airborne measurements, from stations across Europe and a zeppelin measuring above Po Valley. The ground level concentrations of particles with a diameter larger than 100 nm (N-100) were reproduced with a daily normalized mean error of 40% and a daily normalized mean bias of -20 %. PMCAMx-UF tended to overestimate the concentration of particles with a diameter larger than 10 nm (N-10) with a daily normalized mean bias of 75 %. The model was able to reproduce, within a factor of 2, 85% of the N-10 and 75% of the N-100 zeppelin measurements above ground. The condensation of organics led to an increase (50 %-120 %) in the N-100 concentration mainly in central and northern Europe, while the N-10 concentration decreased by 10 %-30 %. Including the VBS in PMCAMx-UF improved its ability to simulate aerosol number concentration compared to simulations neglecting organic condensation on ultrafine particles.
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6.
  • Petzold, Andreas, et al. (author)
  • Creating ENVRI-hub, the Open-Access Platform of the Environmental Sciences Community in Europe
  • 2021
  • In: ; , s. 04-53
  • Conference paper (other academic/artistic)abstract
    • Environmental research infrastructures designed for monitoring all domains of the Earth system (oceans, atmosphere, ecosystems, and solid earth) contribute to global observing systems and serve as crucial information sources for environmental scientists in their quest for understanding and interpreting the complex Earth System. The EU funded ENVRI-FAIR project builds on the Environmental Research Infrastructure (ENVRI) community that includes principal European producers and providers of environmental research data and services. The backbone of the project is the existing IT infrastructure of participating research infrastructures. ENVRI-FAIR targets the development and implementation of both technical frameworks and policy solutions that make scientific boundaries seamlessly traversable for environmental scientists and prepare a holistic approach to Earth system science for the new Open Science paradigm. Cross-discipline harmonization and standardization activities, together with the implementation of joint data management and access structures at the research infrastructure level, facilitate the strategic coordination of observation systems, required for interdisciplinary science. ENVRI-FAIR will create the open access ENVRI-hub delivering environmental and earth science services provided by the contributing environmental research infrastructures. The architecture and functionalities of the ENVRI-hub are driven by the applications, use cases and user needs, and will be based on three main pillars: (1) the ENVRI Knowledge Base and Training Platform as resources for knowledge, services, training, and other digital assets; (2) the ENVRI Catalogue as machine-actionable interface to the ENVRI ecosystem; and (3) interdisciplinary use cases as demonstrators for the capabilities of service provision among environmental research infrastructures and across science clusters. The architecture, design features, technology developments and associated policies are designed in anticipation of interoperation with the European Open Science Cloud (EOSC). The ENVRI-hub is intended to act as a key platform for researchers, other users and developers planning to include ENVRI data-services in their workflows through EOSC resources.
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7.
  • Petzold, Andreas, et al. (author)
  • Opinion : New directions in atmospheric research offered by research infrastructures combined with open and data-intensive science
  • 2024
  • In: Atmospheric Chemistry and Physics. - 1680-7316. ; 24:9, s. 5369-5388
  • Research review (peer-reviewed)abstract
    • The acquisition and dissemination of essential information for understanding global biogeochemical interactions between the atmosphere and ecosystems and how climate-ecosystem feedback loops may change atmospheric composition in the future comprise a fundamental prerequisite for societal resilience in the face of climate change. In particular, the detection of trends and seasonality in the abundance of greenhouse gases and short-lived climate-Active atmospheric constituents is an important aspect of climate science. Therefore, easy and fast access to reliable, long-Term, and high-quality observational environmental data is recognised as fundamental to research and the development of environmental forecasting and assessment services. In our opinion article, we discuss the potential role that environmental research infrastructures in Europe (ENVRI RIs) can play in the context of an integrated global observation system. In particular, we focus on the role of the atmosphere-centred research infrastructures ACTRIS (Aerosol, Clouds and Trace Gases Research Infrastructure), IAGOS (In-service Aircraft for a Global Observing System), and ICOS (Integrated Carbon Observation System), also referred to as ATMO-RIs, with their capabilities for standardised collection and provision of long-Term and high-quality observational data, complemented by rich metadata. The ATMO-RIs provide data through open access and offer data interoperability across different research fields including all fields of environmental sciences and beyond. As a result of these capabilities in data collection and provision, we elaborate on the novel research opportunities in atmospheric sciences which arise from the combination of open-Access and interoperable observational data, tools, and technologies offered by data-intensive science and the emerging collaboration platform ENVRI-Hub, hosted by the European Open Science Cloud (EOSC).
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8.
  • Rosenfeld, Daniel, et al. (author)
  • Global observations of aerosol-cloud-precipitation-climate interactions
  • 2014
  • In: Reviews of Geophysics. - 8755-1209. ; 52:4, s. 750-808
  • Research review (peer-reviewed)abstract
    • Cloud drop condensation nuclei (CCN) and ice nuclei (IN) particles determine to a large extent cloud microstructure and, consequently, cloud albedo and the dynamic response of clouds to aerosol-induced changes to precipitation. This can modify the reflected solar radiation and the thermal radiation emitted to space. Measurements of tropospheric CCN and IN over large areas have not been possible and can be only roughly approximated from satellite-sensor-based estimates of optical properties of aerosols. Our lack of ability to measure both CCN and cloud updrafts precludes disentangling the effects of meteorology from those of aerosols and represents the largest component in our uncertainty in anthropogenic climate forcing. Ways to improve the retrieval accuracy include multiangle and multipolarimetric passive measurements of the optical signal and multispectral lidar polarimetric measurements. Indirect methods include proxies of trace gases, as retrieved by hyperspectral sensors. Perhaps the most promising emerging direction is retrieving the CCN properties by simultaneously retrieving convective cloud drop number concentrations and updraft speeds, which amounts to using clouds as natural CCN chambers. These satellite observations have to be constrained by in situ observations of aerosol-cloud-precipitation-climate (ACPC) interactions, which in turn constrain a hierarchy of model simulations of ACPC. Since the essence of a general circulation model is an accurate quantification of the energy and mass fluxes in all forms between the surface, atmosphere and outer space, a route to progress is proposed here in the form of a series of box flux closure experiments in the various climate regimes. A roadmap is provided for quantifying the ACPC interactions and thereby reducing the uncertainty in anthropogenic climate forcing.
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9.
  • Wittenburg, Peter, et al. (author)
  • State of fairness in esfri projects
  • 2020
  • In: Data Intelligence. - : MIT Press - Journals. - 2096-7004 .- 2641-435X. ; 2:1-2, s. 230-237
  • Journal article (peer-reviewed)abstract
    • Since 2009 initiatives that were selected for the roadmap of the European Strategy Forum on Research Infrastructures started working to build research infrastructures for a wide range of research disciplines. An important result of the strategic discussions was that distributed infrastructure scenarios were now seen as “complex research facilities” in addition to, for example traditional centralised infrastructures such as CERN. In this paper we look at five typical examples of such distributed infrastructures where many researchers working in different centres are contributing data, tools/services and knowledge and where the major task of the research infrastructure initiative is to create a virtually integrated suite of resources allowing researchers to carry out state-of-the-art research. Careful analysis shows that most of these research infrastructures worked on the Findability, Accessibility, Interoperability and Reusability dimensions before the term “FAIR” was actually coined. The definition of the FAIR principles and their wide acceptance can be seen as a confirmation of what these initiatives were doing and it gives new impulse to close still existing gaps. These initiatives also seem to be ready to take up the next steps which will emerge from the definition of FAIR maturity indicators. Experts from these infrastructures should bring in their 10-years’ experience in this definition process.
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  • Result 1-9 of 9

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