Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2009
Sammendrag
Colour has increased significantly in several Norwegian rivers and lakes over the past two - three decades (Haaland et al. 2007; de Wit et al. 2007). This has also been observed throughout Northern hemisphere (Forsberg and Petersen 1990; Freeman et al. 2001; Roulet and Moore 2006; Tranvik and Jansson 2002). The long term increase in colour has coincided with the decline in anthropogenic acid emissions which peaked in Europe around mid 1970s (Schöpp et al. 2003). During the earlier days of the acid rain history, Krug and Frink (1983) hypothesised that acid rain possibly could explain the previously reduced colour in lakes observed on the Northern hemisphere. The increase in colour and concentrations of organic carbon in lakes throughout the past decades have by several authors again been linked to the reduction of atmospheric acid emission, in the UK (Evans et al. 2006), in Norway (de Wit et al. 2007) and in northern Europe and northern America (Monteith et al. 2007).
Sammendrag
Side effects related to liming have been studied in four dimictic lakes (553-642 m a.s.l.; 59°57"N) in Finnemarka, a forested area in Southern Norway with poor catchment buffer capacity. Data series from lake profiles have been sampled two decades apart; 10 years prior to liming and after 10 years of liming. Water samples were collected during spring after ice breakup, and during summer after the development of thermal stratification. Before liming, there were very low concentrations of bicarbonate (HCO3-) (or alkalinity) in the lakes.After 10 years of liming, up to 90 % of the ions in hypolimnion originate from lime products. Hence; liming strengthened the chemical stratification and increased the vertical stability. Differences in chemocline developments between lakes were explained by differences in physical properties, i.e. their depth/surface area ratio. The chemocline developments lead to increased concentrations of organic matter in the hypolimnion, with a subsequent reduction in oxygen concentrations. Lime additions during late spring, as an alternative to early autumn, lead to pronounced anoxic conditions in the hypolimnion.
Sammendrag
Throughout the past few decades there has been a significant increase in TOC concentrations in several Norwegian lakes. Monitored lakes with limited or no buffer capacity (Chloride- and Sulphate-lakes), and especially the Sulphate-lakes (which have had a more pronounced decline in ionic strength related to the reduced anthropogenic acid components in precipitation), have had a significantly percentage increase in TOC concentrations throughout the past 15 yrs. Lakes with some buffer capacity (ANC-lakes) have not had a significant percentage increase in TOC concentrations throughout the same period.
Sammendrag
Within the scope of the ClimRunoff project, it is necessary to develop an accurate method for estimating peak discharges for the purpose of correctly sizing hydraulic structures at road and rail crossings. The presence of a snowpack and/or ice has an impact on the way the watershed will react to rain events. The first step in understanding the effects of the changing climate is to understand the reaction of the catchment to situations that are happening in today"s climate. After correctly modeling the processes currently occurring during cold seasons today, future scenarios can be modeled to see what effects changes in precipitation patterns and temperatures will have on catchment hydrology. The overall goal of this work is to provide an accurate estimate of runoff water produced from snowmelt on a catchment scale in order to support the development of more accurate methods of estimating peak discharge for road drainage structures. Use is made of the Utah Energy Balance model and the LISEM model. The coupling of the UEB and LISEM models provides valuable insight into the hydrological processes and responses occurring during winter periods. However, more work is needed to improve our understanding and quantification of soil-water interactions during cold periods, which can cause great deviations from hydrologic processes observed during warmer periods.
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Forfattere
Jannes StolteSammendrag
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Forfattere
Hallvard JensenSammendrag
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Forfattere
Csilla FarkasSammendrag
The latest climate change scenarios, forecasting for the Tisza watershed valuable increase in the occurrence of extreme weather events as well as changes in land use policy increased the demand on knowledge towards sustainable flood plain and water reservoir management. The main objective of the present study was to develop an appropriate methodology that could be used for describing the soil water regime of the Bodrog Interfluve floodplain area at sub-regional scale and to derive the corresponding soil and hydrological database. This paper describes the fine-scale spatial soil database, constructed for characterizing the soil cover of the Hungarian territory of the Bodrog Region; the monitoring system, established in the study area and the mathematical modeling procedure carried out for better description of soil water regime and water balance elements. Further, performance and results of a scenario analyses are presented for evaluating the possible effects of two recently predicted climate change scenarios on soil water regime of a sensitive floodplain area. It was concluded, that based on the adaptation of a water balance simulation model and on the spatial soil physical database, the water regime of the dominant natural, semi-natural and agrarian ecosystems could be estimated. Compared to the present circumstances, the results of the scenarios analyses indicated more uneven and extreme surface and subsurface hydrological situations under changing climatic conditions.