Alenius, P., Myrberg, K. & Nekrasov, A. 1998. The physical oceanography of the Gulf of Finland: a review. Boreal Env. Res. 3(2): 97–125.
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Kitaigorodskii, S.A. 1998. Wind wave breaking and aerodynamic roughness of the air-sea interface as seen from above and from below. Boreal Env. Res. 3(2): 127–136.
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Elo, A.-R., Huttula, T., Peltonen, A. & Virta, J. 1998. The effects of climate change on the temperature conditions of lakes. Boreal Env. Res. 3(2): 137–150.
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Salmi, P. 1998. Towards sustainable vendace fisheries? Fishermen’s conceptions about fisheries management. Boreal Env. Res. 3(2): 151–159.
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Steedman, R.J., France, R.L., Kushneriuk, R.S. & Peters, R.H. 1998. Effects of riparian deforestation on littoral water temperatures in small Boreal forest lakes. Boreal Env. Res. 3(2): 161–169.
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Venäläinen, A., Solantie, R. & Laine, V. 1998. Mean long-term surface energy balance components in Finland during the summertime. Boreal Env. Res. 3(2): 171–180.
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Paatero, J. & Jaakkola, T. 1998. Transfer of plutonium, americium and curium from fallout into reindeer after the Chernobyl accident. Boreal Env. Res. 3(2): 181–189.
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Uuttera, J., Matti Maltamo, M., Kurki, S. & Mykrä, S. 1998. Differences in forest structure and landscape patterns between ownership groups in Central Finland. Boreal Env. Res. 3(2): 191–200.
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Alenius, P., Myrberg, K. & Nekrasov, A. 1998. The physical oceanography of the Gulf of Finland: a review. Boreal Env. Res. 3(2): 97–125.
The Gulf of Finland is today an actively-investigated sea area. Basin-wide studies are carried out in an international cooperation between all the coastal states of the gulf. Understanding of the basic physics of the gulf is vital in order to assess the state of the marine environment and to construct coupled hydrodynamic-ecological models for describing the response of the sea to human activities. This paper is a literature review of the physical features of the Gulf of Finland. Our main interest is the general circulation as well as the horizontal and vertical structure of water masses, but surface waves, the sea level, ice conditions and air-sea interaction are also briefly reviewed. Special attention has been paid to the eastern end of the gulf, which is an important mixing area and buffer zone for pollutants.
Kitaigorodskii, S.A. 1998. Wind wave breaking and aerodynamic roughness of the air-sea interface as seen from above and from below. Boreal Env. Res. 3(2): 127–136.
In this paper an attempt is made to explain some of the features of classical aerodynamic classification based on the effect of mobility of roughness elements (Kitaigorodskii 1968) for both sides of the air-sea interface by incorporating into such a classification the effect of breaking wind waves. Also the "fluctuating" regime of the sea surface roughness discussed by Toba et al. (1991) is explained by taking into account the existence of the dissipation subrange (Kitaigorodskii 1983, 1986, 1992a, 1992b, 1997) and the inverse cascade of energy in the well developed wind wave field (Zaharoff and Zaslavskii 1982, and Kitaigorodskii 1983). In the last section of the paper a theory is proposed on how to incorporate the effect of wave breaking in the parametrization of the sea surface roughness as seen from below. It is shown that aerodynamically smooth conditions in the classical sense never exist below the sea surface, since effective turbulent viscosity due to shear free turbulence generated by wave breaking is much larger than molecular viscosity.
Elo, A.-R., Huttula, T., Peltonen, A. & Virta, J. 1998. The effects of climate change on the temperature conditions of lakes. Boreal Env. Res. 3(2): 137–150.
Climate change, as indicated by changes in air temperature, was simulated with the SILMU (the Finnish Research Programme on Climate Change) scenarios. The effects of air temperature change on the temperature regime of five lakes were studied with a temperature model using two approaches. The parameters describing the temperature regime were vertical temperature distribution, length of the stratification period, time of freezing and time of ice break-up. The surface areas of the lakes range from 0.25 km2 to 161 km2 and depths from 13 to 85 m. For one lake (Pääjärvi) the averages and the standard deviations of the temperature parameters in a changing climate were computed for the years 2036–2065. For the year 2050 (June-August) the surface temperature increases by 1.8deg.C, and the low and high estimates are 0.5deg.C and 2.6deg.C. For the other lakes a spatial approach was used. Representative values for air temperature in the years 2020, 2050 and 2090 were used to obtain a spatial description of the temperature regime of small lakes all over Finland. All the results showed significant changes in the temperature regime, e.g. changes of 30–60 days were predicted in the length of stratification and ice-covered period.
Salmi, P. 1998. Towards sustainable vendace fisheries? Fishermen’s conceptions about fisheries management. Boreal Env. Res. 3(2): 151–159.
The management and sustainability of commercial vendace fisheries in Finnish lakes were studied from the point of view of the fishermen. Their attitudes, problems and proposals for better arrangements were examined and the implications for the development of the fishery system were discussed. From the perspective of the fishermen, the main management problem is the lack of fishing opportunities due to the restrictive policy of the fishery associations. The fishermen feel they have been neglected by the local level of management and would rather rely on the state level and its district authorities. The attitudes towards ecological sustainability of vendace stocks varied widely. In many cases regulations were considered important in order to protect the fish resources. However, the fishermen also needed regulations to enhance socioeconomic sustainability. The commercial fishermen should be integrated more closely into the decision-making regime in order to reduce the likelihood of conflict.
Steedman, R.J., France, R.L., Kushneriuk, R.S. & Peters, R.H. 1998. Effects of riparian deforestation on littoral water temperatures in small Boreal forest lakes. Boreal Env. Res. 3(2): 161–169.
In a four-month comparison of hourly littoral water temperatures in four small boreal lakes, recent shoreline deforestation was associated with an altered temperature regime at only one lake, on a southern shoreline. There, daytime hourly median water temperatures were increased by 0.3deg.C, with frequent increases of 0.5deg.C and occasional increases of up to 1.2deg.C, relative to a nearby forested shoreline; nighttime temperatures were reduced by about 0.2deg.C. Over about three months, the littoral zone of the deforested southern shoreline accumulated only about one-half of a degree day more than the forested shoreline. Time-series analyses of hourly climate data and water temperature patterns from two nearby undisturbed lakes suggest that hourly littoral water temperature patterns were primarily associated with hourly patterns of solar energy, while day-to-day water temperature patterns were associated only with air temperature. Where riparian deforestation significantly reduces littoral shading, the main effect on littoral water temperatures is likely to be an increase in diurnal temperature fluctuation. Daily average water temperatures are strongly associated with regional air temperature, and are not likely to be affected significantly by localized riparian deforestation.
Venäläinen, A., Solantie, R. & Laine, V. 1998. Mean long-term surface energy balance components in Finland during the summertime. Boreal Env. Res. 3(2): 171–180.
The long-term, 1961–1990, mean summertime surface energy balance components in Finland were estimated by making use of earlier published studies for the estimation of the global radiation, surface albedo and latent heat flux. The net long-wave radiation was estimated with the help of synoptic cloud observations, and the sensible heat flux was calculated as the remainder in the energy balance equation. The results are presented both on a 10 km x 10 km grid and as climate-zone averages. The lowest values of global radiation, about 170 W m–2, were found in north-eastern Lapland. There was also a local minimum of about 190 W m–2 over the Suomenselkä divide and southern Ostrobothnia. The maximum values of about 220 W m–2 were found along the coast of the Baltic Sea. The cooling of the surface due to net long-wave radiation was smallest in northern Lapland, about –35 W m–2, elsewhere the spatial variation was very small, and the net long-wave radiation was from –40 to –45 W m–2. The highest values of evaporation occured in southern Finland, where the latent heat flux was about –80 W m–2, and the minimum in Lapland with a value of about –35 W m–2. The highest sensible heat fluxes were located along the coast and in Lapland, and the smallest in the inland areas of southern Finland. The difference in the sensible heat flux between the climate zones was small.
Paatero, J. & Jaakkola, T. 1998. Transfer of plutonium, americium and curium from fallout into reindeer after the Chernobyl accident. Boreal Env. Res. 3(2): 181–189.
Several reindeer tissue samples were analysed for transuranium elements following the Chernobyl accident in 1986. Pu, Am and Cm were separated using coprecipitation and anion exchange steps, and measured with alpha spectrometry. The activity concentrations of 239,240Pu in reindeer liver found in this study (0.0094–0.062 Bq kg–1 d.w. [= dry weight]) are low compared to the concentrations found in the 1960s and 1970s, even though most of the samples are from the areas with the heaviest Chernobyl-derived fallout of plutonium. On the other hand, the 241Pu concentrations in reindeer liver found in this study (0.7–3.9 Bq kg–1 d.w.) are comparable to earlier results. The calculated transfer factors, (0.31–1.61) x 10–5 m2 kg–1 for 239,240Pu and 7 x 10–3 m2 kg–1 for 241Am, show that 137Cs migrates from fallout to reindeer meat 100 times more efficiently than 241Am and 10000 times more efficiently than 239,240Pu. The transfer factor of 2 x 10–3 m2 kg–1 obtained for 242Cm does not take into account the physical decay of 242Cm. Several earlier results concerning plutonium and americium in reindeer could be verified in this study using the fallout from the Chernobyl accident. Americium and curium are accumulated more efficiently than plutonium in bone and lungs. The main pathway of Pu, Am and Cm into reindeer is the gastro-intestinal (GI) tract and not inhalation. The absorption coefficient of 239,240Pu obtained for the GI-tract, 3.0 x 10–5, is in agreement with earlier results. A GI-tract absorption coefficient of 7.5 x 10–4 for 241Am was obtained in this study.
Uuttera, J., Matti Maltamo, M., Kurki, S. & Mykrä, S. 1998. Differences in forest structure and landscape patterns between ownership groups in Central Finland. Boreal Env. Res. 3(2): 191–200.
The spatial distribution and connectivity of forest characteristics, such as soil productivity, stage of forest development, forest tree species composition and forest vertical structure, were studied according to forest ownership groups in Central Finland. The study was based on the data from the Finnish National Forest Inventory. The spatial distribution was examined by estimating variograms for compared characteristics. Connectivity of forest characteristics was estimated along the inventory track by calculating the proportions of adjacent sample plots which had the same value of the forest characteristic in question. Results on the spatial distribution and connectivity of dominating tree species, tree species composition and vertical structure of the stand show that differences in stand management have also affected the structure of forest landscape. It seems that the within-stand heterogeneity, required by many forest species, is better maintained in privately owned forests due to more heterogeneous management regimes. This leads to greater spatial correlation and connectivity of the stand structure characteristics. On the other hand, small management units in privately owned forest holdings lead to a more fragmented forest landscape. This is partly avoided in forests owned by the state or forest industrial companies, which have more continuous patches of a single successional stage of forest. However, this can be regarded only as a potential for the preservation of viable forest species populations in the future, because currently successional stages of young forest have the greatest spatial correlation and connectivity.