| 1. |
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| 2. |
- Bring, Arvid, et al.
(författare)
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Current status of Pan-Arctic hydrologic and hydrochemical observing networks
- 2007
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Ingår i: Proceedings from the Arctic Coastal Zones at Risk workshop in Tromsö, Norway, 1-3 October 2007.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Access to reliable hydrologic and hydrochemical data is of paramount importance for accurately understanding and modeling ongoing change in the Arctic hydrologic cycle under a warming climate. Recent studies have shown that the availability of and accessibility to such data is limited, and also declining, for some Arctic areas. In particular, there is a lack of consistent monitoring of water chemistry. At the same time, there is little information on where and which data gaps are most critical.In light of the present decline of monitoring, it is important to compile and quantify the hydrological and water chemistry monitoring in the Arctic. It is further important to investigate whether there are any systematic differences in characteristics between monitored and unmonitored areas draining to the Arctic Ocean, as such biases might limit the ability of models to accurately predict hydrologic behavior across basins with different properties.We present a quantitative assessment of all openly available monitoring data for water discharge and important water chemistry parameters (carbon, nitrogen, phosphorus and sediment) in the pan-Arctic drainage basin.Openly accessible pan-Arctic monitoring data were assembled from various databases for discharge and water chemistry, and monitoring station locations were co-referenced to a 30-minute simulated topological network. This allowed the construction of a geographically distributed representation of the temporal and spatial extent of monitoring. By linking this information with spatially distributed basin properties, differences in characteristics between monitored and unmonitored areas were analyzed. Finally, spatial patterns in the recent decline of discharge monitoring were compared with recently observed and projected future temperature trends.Results indicate significant disparity in the spatial and temporal distribution of monitoring data, in particular for water chemistry monitoring, which is both spatially and temporally much less extensive than discharge monitoring. Additionally, there are systematic differences between the characteristics of monitored and unmonitored areas, within and between the different continents in the pan-Arctic drainage basin. The decline in network density has been greatest in four Eurasian basins. In these areas, recent observational temperature trends have been the smallest, while climate models predict the greatest future increases in these areas.The scarcity of water chemical data and the systematic differences in characteristics between monitored and unmonitored basins may limit the reliability of assessments of Arctic water and hydrochemical flux changes under a warming climate. Observed and modeled climate trends exhibit diverging spatial patterns, which makes it difficult to determine whether the basins with the greatest decline in discharge monitoring density are really the ones that will experience the greatest future temperature change. Arctic monitoring needs to be extended in certain areas to enable reliable characterization of hydrologic and hydro-chemical variability and change in the region.
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| 3. |
- Bring, Arvid, et al.
(författare)
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Pan-Arctic drainage basin monitoring: current status and potential significance for assessment of climate change effects and feedbacks
- 2007
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Ingår i: Proceedings of the Third International Conference on Climate & Water. - 9789521127908 ; , s. 88-93
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Access to reliable hydrologic data is of paramount importance for accurately understanding and modeling ongoing change in and climate feedbacks of the Arctic hydrologic cycle. The accessibility to such data is limited, and continues to decline for some Arctic areas, but there is little information on where and which data gaps are most critical. We present a quantitative assessment of openly accessible monitoring data for water discharge and chemistry in the pan-Arctic drainage basin. We also quantify differences in characteristics between monitored and unmonitored areas, and analyze spatial patterns in reported decline of discharge networks in relation to recently observed and future modeled temperature trends. Results indicate that there is significant disparity in the spatial and temporal distribution of monitoring data, in particular for water chemistry monitoring. Additionally, there are systematic differences between the characteristics of monitored and unmonitored areas, within and between the different continents in the pan-Arctic drainage basin. Discharge network density has declined the most in four Eurasian drainage basins, which show the smallest recently observed temperature trends but the greatest modeled future temperature changes. Differences in characteristics between monitored and unmonitored areas may limit the reliability of assessments of Arctic water and solute flux change under a warming climate. Arctic monitoring needs to be extended in certain areas to fully enable characterization of the hydrologic variability and change in the region.
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| 4. |
- Bring, Arvid, et al.
(författare)
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Pan-Arctic Drainage Basin Monitoring: Current Status and Potential Significance for Assessment of Climate Change Impacts and Feedbacks
- 2007
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Ingår i: Arctic Forum Abstract Volume.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Access to reliable hydrologic data is of paramount importance for the accurate understanding of changes in the arctic hydrologic cycle, and is also vital to policymakers as a base for sound environmental decisions. Accessibility to such data is limited and continues to decline for some arctic areas, while little information exists on which data gaps are most critical. This study presents a quantitative assessment of openly available monitoring data for water discharge and chemistry in the pan-arctic drainage basin. Results indicate that there is significant disparity in the spatial and temporal distribution of accessible monitoring data, in particular for water chemistry monitoring. Additionally, there are systematic differences between the characteristics of monitored and unmonitored areas. These differences may limit the reliability of assessments of arctic water and solute flux changes under a warming climate. Arctic monitoring needs to be extended in certain areas, and data needs to be disseminated more efficiently, to fully enable characterization of the hydrologic variability and change in the region.
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| 5. |
- Bring, Arvid, et al.
(författare)
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Pan-Arctic drainage basin observation networks: current status and potential significance for assessment of climate change effects and feedbacks
- 2007
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Ingår i: 1st IPY workshop on Sustaining Arctic Observing Networks.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Hydrological observation networks are integral for understanding and modeling present and future changes in and climate feedbacks to the Arctic environmental system. Recent studies have reported a widespread decline in these networks, but patterns of decline and location of critical data gaps are less certain. We present an updated and quantitative status of openly accessible observation network data for discharge and water chemistry in the pan-Arctic drainage area. We also compare relevant hydrological and socio-economic characteristics of monitored and unmonitored areas, and analyze the decline in network density in relation to recently observed and future modeled temperature trends. Results indicate that there are significant temporal and spatial variations in accessible data, and that there is a critical lack of accessible water chemistry data for large shares of the pan-Arctic. Furthermore, there are systematic differences in characteristics between monitored and unmonitored areas, within and between pan-Arctic regions. Discharge network density has declined the most in four Eurasian drainage basins, which show the smallest recently observed temperature trends but the greatest modeled future temperature changes. Differences in characteristics between monitored and unmonitored areas may limit the reliability of assessments of Arctic water and solute flux change under a warming climate. Improved understanding of the Arctic hydrological system requires less restricted access to monitoring data, extended network coverage of unmonitored areas, and a commitment to sustaining and improving existing networks.
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| 6. |
- Darracq, Amélie, et al.
(författare)
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Nutrient transport scenarios in a changing Stockholm and Mälaren valley region, Sweden
- 2005
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 51:3-4, s. 31-38
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Tidskriftsartikel (refereegranskat)abstract
- Norrstrom catchment, west of Stockholm, covers most of the Malaren valley. Provision of drinking water from Lake Malaren is an absolute precondition for continued growth in the region. Stockholm County's population is expected to increase by 600,000 people before 2030. Current climate change predictions anticipate significant temperature and precipitation increases. We implement the PolFlow model embedded in PCRaster for quantifying water and substances fluxes on the catchment scale over a 30-year time horizon. We formulate scenarios for changes in water quality and quantity due to climate change and population development. Results indicate a mild impact from climate change on surface flow rates but substantial effects on sub-surface residence times. Population development slightly affects nutrients loads. Using source apportionment and sensitivity analysis, we identify a number of critical parameters/processes to be further studied, in order for future results to be more reliable and usable in a water resources management context.
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| 7. |
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| 8. |
- Destouni, Georgia, et al.
(författare)
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Small unmonitored near-coastal catchment areas yielding large mass loading to the sea
- 2008
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Ingår i: Global Biogeochemical Cycles. ; 22:GB4003
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Tidskriftsartikel (refereegranskat)abstract
- Continental freshwater transports and loads excess nutrients and pollutants from various land surface sources into downstream inland and coastal water environments. This study shows that even small, hydrologically unmonitored near-coastal catchment areas may generate large nutrient and pollutant mass loading to the sea of a magnitude similar to or greater than monitored river loads. Systematic near-coastal gaps in the monitoring of freshwater discharges to the sea may therefore mislead the quantification of coastal mass loading significantly. A methodology is presented for quantifying the mass load contributions of all the different unmonitored pathways of hydrological mass transport to the coast, including unmonitored river parts, whole unmonitored streams, and submarine groundwater discharge. This can be used for guiding future efforts to improve monitoring so that it includes the essential hydrological pathways of nutrient and pollutant loading to the sea.
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| 9. |
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| 10. |
- Hannerz, Fredrik, et al.
(författare)
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Assessment of land use and cropland inventories for Africa
- 2006
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Ingår i: CEEPA Discussion Papers. ; 22
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Tidskriftsartikel (refereegranskat)abstract
- For many African countries agriculture will remain an important engine for economic development for decades to come, and the livelihood of rural populations and the welfare of entire countries critically depend on agricultural productivity. At the same time, agricultural practices have enormous consequences for natural systems and threaten the natural resource endowment in many regions. Given the importance of agriculture for sustainable development in Africa it is paramount to develop baselines of land use to monitor and assess the natural and economic impacts of environmental change. This paper critically examines estimates of cropping patterns and cropland extent for Africa produced using various sources of remotely sensed data and compares them with non-spatial statistical inventories of cropland at the continental, regional and local scales. The analysis reveals substantial discrepancies across alternative sources of information about land cover in both the extent and location of croplands, and pinpoints shortcomings in currently available inventories of land cover and land use data derived from remote sensing. These inconsistencies have important implications for downstream analyses that use land use data and they highlight the need to strengthen technological and statistical capacity in the regions to provide the basis forinformed policy decisions.
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| 11. |
- Hannerz, Fredrik, et al.
(författare)
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Assessment of remotely sensed and statistical inventories of African agricultural fields
- 2008
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Ingår i: International Journal of Remote Sensing. - : Informa plc. - 0143-1161 .- 1366-5901. ; 29:13, s. 3787-3804
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Tidskriftsartikel (refereegranskat)abstract
- This paper critically examines different sources of remotely sensed and statistical inventories of African agricultural fields. Substantial discrepancies are found across alternative sources of information in both the extent and location of agricultural fields. In one-third of the countries, the difference between lowest and highest field extent estimate exceeds 25% of the total country area, and the maximum difference at the continental level is 2.6 million km2. Much of the disagreement between land-cover maps arises from areas of low cropping density. These inconsistencies have important implications when using these data directly, e.g. for the assessment of land cover changes, or indirectly in economic or physical models, and indicate a need to explicitly quantify uncertainties arising from the limitations in land-cover data. They also highlight the need for development of regional land information systems for baseline development and informed policy decisions.
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| 12. |
- Hannerz, Fredrik, et al.
(författare)
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Establishing a water information system for Europe : constraints from spatial data heterogeneity
- 2007
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Ingår i: Water and Environment Journal. - : Wiley. - 1747-6585 .- 1747-6593. ; 21:3, s. 200-2007
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Tidskriftsartikel (refereegranskat)abstract
- Water information systems (WIS) are being developed for countries, international river basins and the European Union (EU), partly as a result of the requirements specified in the EU Water Framework Directive (WFD). The issue of whether and how these information systems should be integrated into the European Commission's water information system for Europe (WISE) is currently an open one. We present a discussion with regard to the challenges facing WISE development, with particular focus on the heterogeneity of spatial base data. In addition, an assessment of this heterogeneity is presented based on Swedish and English WFD reporting data, and on WISE-relevant small-scale European base datasets. Results show that WFD reporting data are based on incomparable methods and spatial analysis units, and that small-scale data are transborder heterogeneous. Interpretation and international comparison of WFD results as well as their combination into a common WISE may therefore be largely constrained by spatial data heterogeneity.
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| 13. |
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| 14. |
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| 15. |
- Hannerz, Fredrik, 1977-
(författare)
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Making water information relevant on local to global scale – the role of Information Systems for Integrated Water Management
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Relevant information is essential for finding solutions in Integrated Water Management (IWM). Complex water systems and a need for increasing integration of sectors, actors and scales in IWM require new methods for developing and managing such information. This thesis investigates the role of information within the IWM process, as well as the main challenges for development of representative, accessibleand harmonized information. Results show how information needs and the information production process for IWM may be systematized, and indicate a large potential for information system development for IWM. However, in order to reach the full potential, today’s limited and heterogeneous water information needs to become more comprehensive, transparent, interoperable, dynamic, scalable and openly accessible. Large pressures on water systems are found in coastal catchment areas that are unmonitored across the local to the global scale, indicating a large importance of these areas for nutrient and pollutant loading. The globally accessible runoff data from catchment areas that are rich in pressures from population, agriculture and general economic activity further exhibit a rapidly declining trend during recent years. Major water system changes may therefore pass unnoticed if analyzed on the basis of openly accessible runoff global data. Furthermore, large discrepancies are found between land cover databases, which may result in major uncertainties in quantification of water and evapotranspiration flows. Identified information challenges may be relatively easily overcome by making better use of available information, while other challenges such as development of consistent baselines of core data and a possible re-prioritization of water-environmental monitoring programs may be both difficult and costly.
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| 16. |
- Hannerz, Fredrik, et al.
(författare)
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Spatial characterization of the Baltic sea drainage basin and its unmonitored
- 2006
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Ingår i: Ambio. - 0044-7447. ; 35:5, s. 214-9
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Tidskriftsartikel (refereegranskat)abstract
- We present an updated, harmonized hydrologic base map of the entire Baltic Sea Drainage Basin (BSDB), including 634 subdrainage basins. The updated map has a level of detail approximately 5 to 10 times higher than the current standard and includes various spatial-aggregation possibilities of relevance for water management. All 634 subdrainage basins and their various spatial aggregations are characterized in terms of population, land cover, drainage density, and slope. We identify, quantify, and characterize, in particular, drainage basins that are unmonitored with regard to the combination of water-flow and nutrient-concentration measurements needed to monitor coastal nutrient and pollutant loading. Results indicate that out of a total BSDB population of 84239000 in 2002, 24% lived in unmonitored coastal drainage basins that cover 13% of the total BSDB area. A more detailed analysis of Swedish catchments indicates that Sweden has a particularly large proportion of unmonitored coastal catchment areas (20% of the total Swedish area) with high population pressures (55% of the total Swedish population), when compared with average conditions for the whole BSDB. In general, the investigated characteristics of unmonitored coastal basins vary and differ largely from those in adjacent monitored drainage basins within the BSDB.
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| 17. |
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| 18. |
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| 19. |
- Nilsson, Susanna, et al.
(författare)
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International River Basin Districts under the EU water framework directive : Identification and planned cooperation
- 2004
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Ingår i: European Water Management Online. - 1461-6971. ; , s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- IIn this article the number and geographical extent of prospective international River Basin Districts (RBDs), identified according to the EU Water Framework Directive (WFD), are determined, and the plans and ambitions for international cooperation examined. Further, for illustrating varying approaches in the identification of and cooperation on international RBDs two examples from the prospective RBDs of Estonia and the Danube River basin are given. The study showed that 30% of the prospective RBDs are international. Area wise, the international RBDs constitute 66% of the total area of prospective RBDs. It is, thus, quite clear that the number and area of prospective international RBDs identified under the WFD are significant. Based on this notion, we argue that the "soft" requirements in the WFD concerning international RBDs may undermine the directive's ambition of management according to river basins. The two examples from Estonia and Danube River also showed that the WFD allows for quite different interpretations in the identification and planning of RBDs.
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| 20. |
- Smith, S.V., et al.
(författare)
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River nutrient loads and catchment size
- 2005
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Ingår i: Biogeochemistry. - : Springer. - 0168-2563 .- 1573-515X. ; 75, s. 83-107
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Tidskriftsartikel (refereegranskat)abstract
- We have used a total of 496 sample sites to calibrate a simple regression model for calculating dissolved inorganic nutrient fluxes via runoff to the ocean. The regression uses the logarithms of runoff and human population as the independent variables and estimates the logarithms of dissolved inorganic nitrogen and phosphorus loading with R2 values near 0.8. This predictive capability is about the same as has been derived for total nutrient loading with process-based models requiring more detailed information on independent variables. We conclude that population and runoff are robust proxies for the more detailed application, landscape modification, and in-stream processing estimated by more process-based models. The regression model has then been applied to a demonstration data set of 1353 river catchments draining to the sea from the North American continent south of the Canadian border. The geographic extents of these basins were extracted from a 1-km digital elevation model for North America, and both runoff and population were estimated for each basin. Most of the basins (72% of the total) are smaller than 103 km2, and both runoff and population density are higher and more variable among small basins than among larger ones.While total load to the ocean can probably be adequately estimated from large systems only, analysis of the geographic distribution of nutrient loading requires consideration of the small basins, which can exhibit significant hydrologic and demographic heterogeneity between systems over their range even within the same geographic region. High-resolution regional and local analysis is necessary for environmental assessment and management.
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| 21. |
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