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[en] The Norwegian University of Life Sciences (NMBU) started global radiation (G) measurements in 1949. PAR measurements started in 1978 as part of a Nordic project. The project terminated in 1981, but the measurements continued at NMBU. We have used the data from the Nordic project’s seven stations and the long time series from NMBU to investigate the limitations of using the relative flux density method for the estimation of PAR from G. The yearly mean value of the relative flux density PAR/G at NMBU is 0.48 with a standard deviation of 0.02. The monthly mean values of PAR/G show a seasonal variation, with its maximum (0.50) in late summer and minimum in the winter months (0.45). The seasonal variation corresponds to 15% difference in relative cloud cover. Data from the original Nordic project gave the opportunity to investigate the usability of the relative flux density method in the Nordic area. The flux ratio for July was generally larger than the ratio for September or October, even though the differences are small and not statistically significant. In trying to explain this, one obvious candidate is the cloud cover. In the lack of cloud data, time records of global radiation were used to select fair weather and overcast days. For all stations, fair days show higher flux ratios and overcast days show lower flux ratios. Neglect of cloud cover may lead to an error in the calculation of PAR from the simple formula PAR = constant G of the order of 10%.
[en] Although intensive marine fish farming is often assumed to be eco-friendly, the associated activity can lead to chronic exposure of marine organisms to potentially toxic discharges. Moreover, despite the increasing popularity of integrated multi-trophic aquaculture (IMTA), studies of the effects of fish farm effluents are almost non-existent. In the present study, the changes in the toxic potential of effluents from five land-based marine fish farms in NW Spain subjected for different lengths of time to a biodegradation procedure (for 0, 48, 120, and 240 h) were assessed in a battery of bioassays including organisms from different trophic levels (Vibrio fischeri, Isochrysis galbana, and Paracentrotus lividus). The results of the bioassays at the different times were then considered together with farm water flow in the Potential Ecotoxic Effects Probe (PEEP) index. Despite the high volumes of effluents discharged, the generally low toxicity of the effluents hinders assessment of potentially toxic effects. However, dose–response curves and statistical analysis demonstrated the existence of toxic effects during the first five days of the biodegradation procedure, especially immediately after sampling. The proposed modification of the PEEP index better reflects the changes in toxicity over time. .
[en] This paper describes the status of research in transportation sector with particular attention on reduction of energy consumption and pollutant emission
[it]In questo lavoro si descrivono i possibili contributi alla riduzione dei consumi e delle emissioni che possono derivare da miglioramenti tecnologici di veicoli, propulsori, carburanti e sistemi di controllo
[en] This analysis of the frequency, intensity, and duration of thermal inversions is based on daily minimum (tn) and maximum (tx) temperatures recorded over 3 years at 16 pairs of data loggers located under forest cover in the Jura Mountains of France. Each pair consists of a logger located at the bottom of a depression and another located higher up either nearby (local site) or more than 40 km away (regional site). The daily frequency of inversions is maximum at local sites for tn (50%) and minimum for tx at regional sites (4%). The maximum intensity of the inversions reaches 15.1 °C for tn and 16.2 °C for tx. The average intensity is about 2 °C: 1.5 °C for tx at local sites and 2.4 °C at regional sites. The duration of inversions is generally short: 60% of them last less than a day. Of the inversions that last for more than 1 day, 15% exceed 3 days and the maximum duration observed is 22 days. The relationship between the diurnal amplitude of temperature and the frequency, intensity, and duration of inversions indicates that mesoscale atmospheric conditions directly influence inversions.
[en] Aim of study: To develop a methodology to obtain knowledge in public participation processes. Area of study: Fonsagrada-Os Ancares (Spain), region located in the northern Iberian Peninsula. Material and methods: This study proposes a new method for generating questionnaire survey in participative forest plan with four stages. The validation of this method is performed in the context of a tactical sub-regional forest plan. Main results: The questionnaires based on criteria and indicators proved to be effective in obtaining key information for planning. The method used offers tools to reach the consensus on natural resource management, through the knowledge gained by selecting relevant information (preferences, opinions, and expectations) from past, present, and future forest activity, focusing on solutions to conflicts. Research highlights: The use of appropriate indicators and criteria in the planning phase allows for obtaining knowledge concerning the preferences and future challenges for forest management.
[en] Extratropical cyclones dominate autumn and winter weather over western Europe. The strongest cyclones, often termed windstorms, have a large socio-economic impact due to the strong surface winds and associated storm surges in coastal areas. Here we show that sting jets are a common feature of windstorms; up to a third of the 100 most intense North-Atlantic winter windstorms over the last two decades satisfy conditions for sting jets. The sting jet is a mesoscale descending airstream that can cause strong near-surface winds in the dry slot of the cyclone, a region not usually associated with strong winds. Despite their localized transient nature, these sting jets can cause significant damage, a prominent example being the storm that devastated southeast England on 16 October 1987. We present the first regional climatology of windstorms with sting jets. Previously analysed sting-jet cases appear to have been exceptional in their track over northwest Europe rather than in their strength. (letter)