Browsing by Subject "mallit"

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Now showing items 1-20 of 151
  • Kangas, Jyrki; Pukkala, Timo (Suomen metsätieteellinen seura, 1992)
  • Saramäki, Jussi (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1992)
  • Kilkki, Pekka; Pökälä, Raimo (Suomen metsätieteellinen seura, 1975)
  • Peltola, Heli; Kellomäki, Seppo (Suomen metsätieteellinen seura, 1993)
  • Tan, Jimin (Suomen metsätieteellinen seura, 1987)
  • Mäkelä, A.; Hari, P.; Kellomäki, Seppo (Suomen metsätieteellinen seura, 1981)
  • Kellomäki, Seppo; Väisänen, Hannu; Hänninen, Heikki; Kolström, Taneli; Lauhanen, Risto; Mattila, Ulla; Pajari, Brita (Suomen metsätieteellinen seura, 1992)
  • Kellomäki, Seppo; Hänninen, Heikki; Kolström, Taneli; Kotisaari, Ahti; Pukkala, Timo (Suomen metsätieteellinen seura, 1987)
  • Omwami, Raymond K. (Suomen metsätieteellinen seura, 1986)
  • Lappi, Juha; Siitonen, Markku (Suomen metsätieteellinen seura, 1985)
  • Grennfelt, Peringe; Engleryd, Anna; Forsius, Martin; Hov, Oystein; Rodhe, Henning; Cowling, Ellis (Springer Nature, 2020)
    Because of its serious large-scale effects on ecosystems and its transboundary nature, acid rain received for a few decades at the end of the last century wide scientific and public interest, leading to coordinated policy actions in Europe and North America. Through these actions, in particular those under the UNECE Convention on Long-range Transboundary Air Pollution, air emissions were substantially reduced, and ecosystem impacts decreased. Widespread scientific research, long-term monitoring, and integrated assessment modelling formed the basis for the policy agreements. In this paper, which is based on an international symposium organised to commemorate 50 years of successful integration of air pollution research and policy, we briefly describe the scientific findings that provided the foundation for the policy development. We also discuss important characteristics of the science–policy interactions, such as the critical loads concept and the large-scale ecosystem field studies. Finally, acid rain and air pollution are set in the context of future societal developments and needs, e.g. the UN’s Sustainable Development Goals. We also highlight the need to maintain and develop supporting scientific infrastructures.
  • Laine, Marko (2008)
    Finnish Meteorological Institute Contributions
  • Tattari, Sirkka (National Board of Waters and the Environment. Vesi- ja ympäristöhallitus, 1994)
    Publications of the Water and Environment Research Institute. 17
    Yhteenveto: Haihdunnan mittaamisesta ja mallintamisesta peltoalueella
  • Omwami, Raymond K. (Suomen metsätieteellinen seura, 1988)
    A study aimed at applying concepts of economic theory relevant to the formulation of a long-term timber production model as a basis of forest policy. A vertically integrated forest sector production model is described, together with its application in a developing economy and the derivation of a dynamic silvicultural investment criterion (in a labour surplus economy).
  • Hämäläinen, Jouko; Kuula, Markku (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1992)
  • Valsta, Lauri. (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1992)
  • Mykkänen, Reijo (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1994)
    The study presents a theory of utility models based on aspiration levels, as well as the application of this theory to the planning of timber flow economics. The first part of the study comprises a derivation of the utility-theoretic basis for the application of aspiration levels. Two basic models are dealt with: the additive and the multiplicative. Applied here solely for partial utility functions, aspiration and reservation levels are interpreted as defining piecewisely linear functions. The standpoint of the choices of the decision-maker is emphasized by the use of indifference curves. The second part of the study introduces a model for the management of timber flows. The model is based on the assumption that the decision-maker is willing to specify a shape of income flow which is different from that of the capital-theoretic optimum. The utility model comprises four aspiration-based compound utility functions. The theory and the flow model are tested numerically by computations covering three forest holdings. The results show that the additive model is sensitive even to slight changes in relative importances and aspiration levels. This applies particularly to nearly linear production possibility boundaries of monetary variables. The multiplicative model, on the other hand, is stable because it generates strictly convex indifference curves. Due to a higher marginal rate of substitution, the multiplicative model implies a stronger dependence on forest management than the additive function. For income trajectory optimization, a method utilizing an income trajectory index is more efficient than one based on the use of aspiration levels per management period. Smooth trajectories can be attained by squaring the deviations of the feasible trajectories from the desired one.
  • Korhonen, Kari T. (Suomen metsätieteellinen seura, 1992)
  • Khan, Uzair Akbar; Postila, Heini; Kujala, Katharina; Heiderscheidt, Elisangela; Ronkanen, Anna-Kaisa (Elsevier, 2022)
    Ecological Engineering
    The HYDRUS wetland module is widely used together with the biokinetic model CWM1 to simulate reactive transport of contaminants in constructed wetlands. However, this approach has not been used previously to simulate processes in peat-based wetlands operating in cold climates and treating mining-influenced water. In this study, the goal was to clarify changes in flow, transport, and nitrogen removal processes in cold climate treatment peatlands by assessing the performance of HYDRUS-CWM1. Flow and non-reactive transport of tracer, and reactive transport of ammonium, nitrite, and nitrate, in two pilot wetlands operated under controlled conditions representing frozen (winter) and frost-free (summer) periods were simulated. Model simulation outputs were compared against data obtained from the pilot wetlands and from a full-scale treatment peatland treating mining-influenced water in an Arctic region. Initial peaks in tracer concentration were simulated satisfactorily, but transformation and transport of nitrogen species in treatment peatlands, especially under partially frozen conditions, were modeled with only limited success. Limitations of the model and the assumptions made for the simulations have been discussed to highlight the challenges in modeling of treatment peatlands. Highlights • Initial peaks in tracer concentration were simulated satisfactorily. • Transport of nitrogen especially in winter was modeled with limited success. • Limitations of the model and possibilities for improvement are discussed. • Possibility to use multiple HYDRUS add-ons simultaneously may be critical.