| 1. |
- Callaghan, Terry V., et al.
(författare)
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Ecosystem change and stability over multiple decades in the Swedish subarctic : complex processes and multiple drivers
- 2013
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Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 368:1624
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Tidskriftsartikel (refereegranskat)abstract
- The subarctic environment of northernmost Sweden has changed over the past century, particularly elements of climate and cryosphere. This paper presents a unique geo-referenced record of environmental and ecosystem observations from the area since 1913. Abiotic changes have been substantial. Vegetation changes include not only increases in growth and range extension but also counterintuitive decreases, and stability: all three possible responses. Changes in species composition within the major plant communities have ranged between almost no changes to almost a 50 per cent increase in the number of species. Changes in plant species abundance also vary with particularly large increases in trees and shrubs (up to 600%). There has been an increase in abundance of aspen and large changes in other plant communities responding to wetland area increases resulting from permafrost thaw. Populations of herbivores have responded to varying management practices and climate regimes, particularly changing snow conditions. While it is difficult to generalize and scale-up the site-specific changes in ecosystems, this very site-specificity, combined with projections of change, is of immediate relevance to local stakeholders who need to adapt to new opportunities and to respond to challenges. Furthermore, the relatively small area and its unique datasets are a microcosm of the complexity of Arctic landscapes in transition that remains to be documented.
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| 2. |
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| 3. |
- Yang, Zhenlin, et al.
(författare)
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How can meteorological observations and microclimate simulations improve understanding of 1913-2010 climate change around Abisko, Swedish Lapland?
- 2012
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Ingår i: Meteorological Applications. - : Wiley. - 1350-4827. ; 19:4, s. 454-463
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Tidskriftsartikel (refereegranskat)abstract
- A detailed analysis of 2 years' hourly microclimatic (mainly surface air temperature) data recently acquired from locations widely dispersed over 700 km2 in the Abisko catchment encompassing Lake Tornetrask in Swedish Lapland is presented in this study. This project is designed to explore the effects of microclimatic variability, past and future climate change (1913-2100) on regional vegetation and land-use changes, at an unique Arctic ecological and climate monitoring site, to aid adaptation of stakeholders to future climate change. Dominant altitudinal lapse rate and radiation effects during summer are revealed in detailed analysis of spatial variations in temperature between the different sites, which become largely negated during winter when cold-air ponding is much more significant. Moreover, near-shore temperatures are moderated significantly by Lake Tornetrask during the spring lake-ice melt season. The extent to which synoptic meteorological conditions affect these factors is explored. Examples of gridded temperature maps for the Abisko region are also presented, produced using a downscaling model based on the temperature data, which have numerous ecological and other applications. The long-term Abisko Scientific Research Station meteorological record, which spans almost a century from 1913 to present is also explored, for evidence of climate change, to set the temperature logger data in a long-term climate context. Exploratory analysis of the possible influence of future regional climate change on ecological/vegetation zones is also briefly discussed. Copyright (C) 2011 Royal Meteorological Society
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| 4. |
- Yang, Zhenlin, et al.
(författare)
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Linking Fine-Scale Sub-Arctic Vegetation Distribution in Complex Topography with Surface-Air-Temperature Modelled at 50-m Resolution
- 2012
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Ingår i: Ambio: a Journal of Human Environment. - : Springer Science and Business Media LLC. - 0044-7447. ; 41, s. 292-302
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have shown that the complexities of the surface features in mountainous terrain require a re-assessment of climate impacts at the local level. We explored the importance of surface-air-temperature based on a recently published 50-m-gridded dataset, versus soil variables for explaining vegetation distribution in Swedish Lapland using generalised linear models (GLMs). The results demonstrated that the current distribution of the birch forest and snowbed community strongly relied on the surface-air-temperature. However, temperature alone is a poor predictor of many plant communities (wetland, meadow). Because of diminishing sample representation with increasing altitude, the snowbed community was under-sampled at higher altitudes. This results in underestimation of the current distribution of the snowbed community around the mountain summits. The analysis suggests that caution is warranted when applying GLMs at the local level.
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| 5. |
- Yang, Zhenlin, et al.
(författare)
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Modelling Surface-Air-Temperature Variation Over Complex Terrain Around Abisko, Swedish Lapland: Uncertainties Of Measurements And Models At Different Scales
- 2011
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Ingår i: Geografiska Annaler. Series A. Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 93A:2, s. 89-112
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Tidskriftsartikel (refereegranskat)abstract
- P>Many ecological, physical and geographical processes affected by climate in the natural environment are scale-dependent: determining surface-air-temperature distribution at a scale of tens to hundreds of metres can facilitate such research, which is currently hampered by the relative dearth of meteorological stations and complex surface temperature characteristics, particularly in mountain areas. Here we discuss both the couplings and mismatch of present climatological data at different scales, ranging from similar to 50 m to 100 km, and provide a novel model of the surface-air-temperature distribution in topographically heterogeneous regions. First, a comparison of the large-scale weather station measurements and gridded climate reanalysis (ERA-40) data is used to define regional climatology in the Swedish sub-Arctic and obtain the mesoscale temperature lapse rates. Second, combined with temperature measurements obtained from transects set among complex terrain, key microclimatic characteristics of the temperature distribution are identified, showing few temperature inversions when the wind speed exceeds 3 m s-1, while temperature inversions prevail during calm nights. Besides wind, there is a pronounced winter temperature stratification around the large Lake Tornetrask, and variations in topography are found to have a strong influence in shaping the microscale temperature pattern through their effect on solar radiation during summer. A monthly 50-m scale temperature-distribution (topoclimate) model is built based on the above findings, and model validation is conducted using further fieldwork measurements from different seasons. We present results of surface-air-temperature distribution for the Abisko region, and discuss how these results help reconcile the scale mismatch mentioned above.
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