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Silva Fennica 1926-1997
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Acta Forestalia Fennica
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Articles by Toivo Pohja

Category: Article

article id 5526, category Article
Pertti. Hari, Pasi Aalto, Kaarle Hämeri, Markku. Kulmala, Tapani. Lahti, Sari. Luoma, Lauri Palva, Toivo Pohja, Erkki. Pulliainen, Erkki. Siivola, Timo Vesala. (1994). Air pollution in eastern Lapland : challenge for an environmental measurement station. Silva Fennica vol. 28 no. 1 article id 5526. https://doi.org/10.14214/sf.a9160

The Värriö environmental measurement station has been designed and constructed during 1991 and 1992. The measurement system consists of measurement units for gases (sulphur dioxide, ozone, carbon dioxide), particles, photosynthesis and irradiation. A meteorological station is also included. The preliminary measurement period was started on August, 1991. During the first year (1991–1992) some parts of the system were redeveloped and rebuilt. Full, continuous measurement started in August 1992. The system has been working quite reliably, with good accuracy. The preliminary results show that pollution episodes are observed when the wind direction is from Monchegorsk or Nikel, the main emission sources in Kola Peninsula.

  • Hari, ORCID ID:E-mail:
  • Aalto, ORCID ID:E-mail:
  • Hämeri, ORCID ID:E-mail:
  • Kulmala, ORCID ID:E-mail:
  • Lahti, ORCID ID:E-mail:
  • Luoma, ORCID ID:E-mail:
  • Palva, ORCID ID:E-mail:
  • Pohja, ORCID ID:E-mail:
  • Pulliainen, ORCID ID:E-mail:
  • Siivola, ORCID ID:E-mail:
  • Vesala, ORCID ID:E-mail:
article id 5405, category Article
Pertti Hari, Eeva Korpilahti, Toivo Pohja, Pentti K. Räsänen. (1990). A field system for measuring the gas exchange of forest trees. Silva Fennica vol. 24 no. 1 article id 5405. https://doi.org/10.14214/sf.a15557

A third generation of forest tree gas exchange measuring system design for the use in the field is described. The system is designed to produce data for determining the dependence of the rate of tree photosynthesis, respiration and transpiration on environmental factors. The system consists of eight cuvettes, a tubing system, two infrared gas analysers, an air flow controller, a data logger, and a computer. The measuring cuvette is a clap type, i.e. it is mostly open, only closing during measurement. CO2 exchange is measured as the change in the cuvette concentration of CO2, and, transpiration is measured as the increase in water vapour concentration while the cuvette is closed. The environmental factors measured are temperature, irradiance and air pressure. The system was planned in 1987 and constructed in 1988. It worked reliably in late summer 1988 and the quality of data seems to be satisfactory. 

The PDF includes an abstract in Finnish.

  • Hari, ORCID ID:E-mail:
  • Korpilahti, ORCID ID:E-mail: eeva.korpilahti@luke.fi
  • Pohja, ORCID ID:E-mail:
  • Räsänen, ORCID ID:E-mail:

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