[en] It is clear from the kinetic energy spectrum published by Vinnichenko in 1970 that the atmospheric fluctuations with periods between about 10 and 100 days form a very important part of the atmospheric flow. These oscillations, often called low-frequency or intra-seasonal fluctuations, could result from an instability of the time-mean flow, from an interaction with the oceans, or from a nonlinear transfer of energy from the faster synoptic-scale eddies. In the present study we concentrate on this last possibility and examine, with the help of atmospheric data and general circulation model (GCM) output, the extent to which the synoptic-scale eddies affect the low-frequency fluctuations

[en] Forest investigations carried out on Olkiluoto aim to monitor the state of the forest ecosystems, quantify Olkiluoto-specific processes taking place in the forests producing input data for the safety assessment of spent nuclear fuel disposal, and follow possible changes in the forest condition resulting from the intensive construction activities currently being carried out in the area. The forest investigations form a part of the monitoring programme being carried out on Olkiluoto Island under the management of Posiva Oy. This report focuses on activities performed on bulk deposition and forest intensive monitoring plots (MRK and FIP plots) in 2009. In general, the deposition levels in 2009 in the open area and in stand throughfall were quite comparable to those in earlier years, although sulphur and calcium depositions were somewhat higher in the open area than in earlier years. The soil solution quality in 2009 was also quite comparable to that in earlier years. The NH₄-N and NO₃-N concentrations were low at all depths in the mineral soil of the FIP plots. There appeared to be a gradual decrease in sulphate concentrations in the mineral soil during the monitoring period. In 2009 the monthly level of transipiration in the Scots pine dominated stand was comparable to previous years (2007-2008). Instead, monthly transpiration in the Norway spruce dominated stand was clearly lower in 2009 than in 2007-2008. Annual total litterfall production was smaller in 2008 than in 2007. The most notable differences between the plots were detected in Al and N concentrations. The Al concentration was higher in living pine needles than in spruce needles. High Al and Fe concentrations were found in remaining litter, and are most likely due to soil dust. The average defoliation level of the pines was 4.6 % and of the spruces 24.1 %, indicating a good crown condition: the pines were classified as non-defoliated and the spruces as slightly defoliated. The minirhizotrone images filmed in 2009 in the FIP stands showed that within the two first growing seasons most of the roots observed as new stayed alive. Therefore, for determining the root turnover rate, the minirhizotrone images will also be taken in the growing season of 2010. (orig.)

[en] Using an atmospheric global spectral model at RPN with T42 horizontal resolution, we have shown that the winter atmosphere in the mid-latitude is capable of reacting to the SST anomalies prescribed in the northwest Atlantic with two different responses. The nature of the response is determined by the climatological conditions of the winter system. Experiments are conducted using either the perpetual November or January conditions, with or without the SST anomalies prescribed. Six 50-day integrations, with positive (or negative) SST anomalies prescribed, initialized from independent November analyses and similarly, four runs initialized from January analyses, have been examined in comparison with their control runs