Change search
Refine search result
123 101 - 107 of 107
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 101.
    van der Velde, Ype
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology. University of Utrecht, Netherlands.
    Vercauteren, Nikki
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Dekker, Stefan C.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Exploring hydroclimatic change disparity via the Budyko framework2014In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 28, no 13, p. 4110-4118Article in journal (Refereed)
    Abstract [en]

    The Budyko framework characterizes landscape water cycles as a function of climate. We used this framework to identify regions with contrasting hydroclimatic change during the past 50years in Sweden. This analysis revealed three distinct regions: the mountains, the forests, and the areas with agriculture. Each region responded markedly different to recent climate and anthropogenic changes, and within each region, we identified the most sensitive subregions. These results highlight the need for regional differentiation in climate change adaptation strategies to protect vulnerable ecosystems and freshwater resources. Further, the Budyko curve moved systematically towards its water and energy limits, indicating augmentation of the water cycle driven by changing vegetation, climate and human interactions. This finding challenges the steady state assumption of the Budyko curve and therefore its ability to predict future water cycles.

  • 102.
    Vercauteren, Nikki
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology. Free University of Berlin, Germany.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Seasonal Influence of Insolation on Fine-Resolved Air Temperature Variation and Snowmelt2014In: Journal of Applied Meteorology and Climatology, ISSN 1558-8424, E-ISSN 1558-8432, Vol. 53, no 2, p. 323-332Article in journal (Refereed)
    Abstract [en]

    This study uses GIS-based modeling of incoming solar radiation to quantify fine-resolved spatiotemporal responses of year-round monthly average temperature within a field study area located on the eastern coast of Sweden. A network of temperature sensors measures surface and near-surface air temperatures during a year from June 2011 to June 2012. Strong relationships between solar radiation and temperature exhibited during the growing season (supporting previous work) break down in snow cover and snowmelt periods. Surface temperature measurements are here used to estimate snow cover duration, relating the timing of snowmelt to low performance of an existing linear model developed for the investigated site. This study demonstrates that linearity between insolation and temperature 1) may only be valid for solar radiation levels above a certain threshold and 2) is affected by the consumption of incoming radiation during snowmelt.

  • 103. Volkmann, Till H. M.
    et al.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
    Gupta, Hoshin V.
    Troch, Peter A.
    Multicriteria design of rain gauge networks for flash flood prediction in semiarid catchments with complex terrain2010In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 46, p. W11554-Article in journal (Refereed)
    Abstract [en]

    Despite the availability of weather radar data at high spatial (1 km(2)) and temporal (5-15 min) resolution, ground-based rain gauges continue to be necessary for accurate estimation of storm rainfall input to catchments during flash flood events, especially in mountainous catchments. Given economical considerations, a long-standing problem in catchment hydrology is to establish optimal placement of a small number of rain gauges to acquire data on both rainfall depth and spatiotemporal variability of intensity during extreme storm events. Using weather radar observations and a dense network of 40 tipping bucket rain gauges, this study examines whether it is possible to determine a reliable "best" set of rain gauge locations for the Sabino Canyon catchment near Tucson, Arizona, USA, given its complex topography and dominant storm track pattern. High-quality rainfall data are used to evaluate all possible configurations of a "practical" network having from one to four rain gauges. A multicriteria design strategy is used to guide rain gauge placement, by simultaneously minimizing the residual percent bias and maximizing the coefficient of correlation between the estimated and true mean areal rainfall and minimizing the normalized spatial mean squared error between the estimated and true spatiotemporal rainfall distribution. The performance of the optimized rain gauge network was then compared against randomly designed network ensembles by evaluating the quality of streamflows predicted using the Kinematic Runoff and Erosion (KINEROS2) event-based rainfall-runoff model. Our results indicate that the multicriteria strategy provided a robust design by which a sparse but accurate network of rain gauges could be implemented for semiarid basins such as the one studied.

  • 104. Wang, Chaozi
    et al.
    McNew, Coy P.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Walter, M. Todd
    Volkman, Till H. M.
    Abramson, Nathan
    Sengupta, Aditi
    Wang, Yadi
    Meira Neto, Antonio Alves
    Pangle, Luke
    Troch, Peter A.
    Kim, Minseok
    Harman, Ciaran
    Dahlke, Helen E.
    Particle tracer transport in a sloping soil lysimeter under periodic, steady state conditions2019In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 569, p. 61-76Article in journal (Refereed)
    Abstract [en]

    Colloid transport through complex and dynamic (i.e. non-steady-state) hydrologic systems is rarely studied, owing to the difficulty of constraining initial and boundary conditions and quantifying colloid-porous media and colloid-colloid interactions in transient flow systems. Here we present a particle tracer experiment conducted on a sloped lysimeter receiving periodic rainfall events for 10 days. Four unique, DNA-labelled particle tracers were injected both in sequence and in parallel, together with a conservative tracer (deuterium), over the course of the first day and allowed to move through the system. Discharge-particle tracer concentration curves and the spatial distribution of particle tracer mass retained in the soil at the end of the experiment were found to be highly dependent on the timing of the tracer injection and the precipitation input and subsequent dynamic response of the water table. Overall, neglecting the total DLT recovery rate, the DLT particle tracer breakthrough trend (DNA-labelled particle tracer 4) was similar to deuterium and decreased over time with the exception of a few peaks later in the experiment. The individual particle tracer breakthrough curves suggest a complex system with different fast transport mechanisms (e.g. capillary barrier and size exclusion effect) and slow retention-release mechanisms (e.g. straining, physical-chemical adsorption), which resulted in particle tracers transferring faster than deuterium in the first 10 h of the experiment but being exceeded by deuterium soon after deuterium started to break through. The experiment not only highlights the interaction of repeated colloidal pollution events in hydrologic systems with different pre-event saturation conditions, but also the benefits of using multiple synchronous or sequential tracer applications to dissect explicit formulations of water flow and colloid transport processes in complex and dynamic hydrological systems. Such explicit process formulations could help improve understanding hydrologically-controlled transport through catchments and the quantitative prediction of these processes with water quality models.

  • 105.
    Winterdahl, Mattias
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Swedish University of Agricultural Sciences, Sweden; Uppsala University, Sweden.
    Laudon, Hjalmar
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Pers, Charlotta
    Bishop, Kevin
    Sensitivity of stream dissolved organic carbon to temperature and discharge: Implications of future climates2016In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 121, no 1, p. 126-144Article in journal (Refereed)
    Abstract [en]

    Dissolved organic carbon (DOC) is a significant constituent in aquatic ecosystems with concentrations in streams influenced by both temperature and water flow pathway dynamics associated with changes in discharge (streamflow). We investigated the sensitivity of DOC concentrations in 12 high-latitude headwater streams to changes in temperature and discharge using a mathematical model. The implications of differences in sensitivities were explored by using downscaled projections of air temperature and discharge to simulate possible trajectories of DOC concentrations in a changing climate. We found two distinct responses: (i) catchments where stream DOC sensitivity was high to temperature but low to discharge and (ii) catchments where stream DOC sensitivity was low to temperature but high to discharge. Streams with strong seasonal DOC dynamics were more sensitive to temperature changes than nonseasonal systems. In addition, stream DOC sensitivity to discharge was strongly correlated with vertical soil water DOC differences in the near-stream zone. Simulations of possible future changes in DOC concentrations indicated median increases of about 4-24% compared to current levels when using projections of air temperature and discharge but even larger increases were observed for base flow concentrations (13-42%). Streams with high-temperature sensitivity showed the largest increases in DOC concentrations. Our results suggest that future climatic changes could bring significant increases in surface water DOC concentrations in boreal and hemiboreal areas but that the response ultimately is dependent on vertical soil solution DOC differences and soil organic carbon distribution.

  • 106.
    Winterdahl, Mattias
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Wallin, Marcus B.
    Huseby Karlsen, Reinert
    Laudon, Hjalmar
    Öquist, Mats
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Decoupling of carbon dioxide and dissolved organic carbon in boreal headwater streams2016In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 121, no 10, p. 2630-2651Article in journal (Refereed)
    Abstract [en]

    Streams and rivers emit large quantities of carbon dioxide (CO2) to the atmosphere. The sources of this CO2 are in-stream mineralization of organic carbon (OC) and CO2 input via groundwater inflow, but their relative importance is largely unknown. In this study, we quantified the role of in-stream OC mineralization as a source of CO2 in a number of nested boreal headwater streams. The results showed that mineralization of stream OC contributed 3% of CO2 supersaturation at time scales comparable to the estimated water travel times in the streams (<24h). Mass balances showed that downstream losses of OC were 3% in low-order streams, whereas up to 16% of the OC was lost in the largest (fourth order) streams. In contrast, 85% of the CO2 was lost along the stream network (longest total stream length=17km). Under the assumption that in-stream OC mineralization was the main source of stream CO2, higher rates of OC mineralization (6% of OC) than those reported across the literature (0.7% of OC) would be required to sustain observed CO2 supersaturation. Further, model results indicated that groundwater inflows were sufficient to sustain observed stream CO2 concentrations. We hence conclude that in-stream OC mineralization was a minor source of CO2 in these boreal headwater systems and that the main source of stream CO2 was inflowing groundwater transporting CO2 originating from soil respiration.

  • 107.
    Ype, van der Velde,
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Lyon,, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Vercauteren, Nikki
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Water balance changes across environmental gradients in Sweden2012Conference paper (Refereed)
123 101 - 107 of 107
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf