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  • 1.
    Beaudon, Emilie
    et al.
    Univ Lapland, Arctic Ctr, Rovaniemi 96101, Finland..
    Arppe, Laura
    Univ Helsinki, Dept Geosci & Geog, FIN-00014 Helsinki, Finland..
    Jonsell, Ulf
    Univ Politecn Madrid, ETSI Telecomun, City Univ, E-28040 Madrid, Spain.;Uppsala Univ, Dept Earth Sci, S-75236 Uppsala, Sweden..
    Martma, Tonu
    Tallinn Univ Technol, Inst Geol, EE-19086 Tallinn, Estonia..
    Moeller, Marco
    Rhein Westfal TH Aachen, Dept Geog, D-52056 Aachen, Germany..
    Pohjola, Veijo A.
    Uppsala Univ, Dept Earth Sci, S-75236 Uppsala, Sweden..
    Scherer, Dieter
    Tech Univ Berlin, Dept Ecol, D-12165 Berlin, Germany..
    Moore, John C.
    Univ Lapland, Arctic Ctr, Rovaniemi 96101, Finland.;Beijing Normal Univ, Coll Global Change, Beijing 100875, Peoples R China.;Beijing Normal Univ, Coll Earth Syst Sci, Beijing 100875, Peoples R China..
    SPATIAL AND TEMPORAL VARIABILITY OF NET ACCUMULATION FROM SHALLOW CORES FROM VESTFONNA ICE CAP (NORDAUSTLANDET, SVALBARD)2011Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 93A, nr 4, s. 287-299Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We analyse ice cores from Vestfonna ice cap (Nordaustlandet, Svalbard). Oxygen isotopic measurements were made on three firn cores (6.0, 11.0 and 15.5 m deep) from the two highest summits of the glacier located on the SWNE and NWSE central ridges. Sub-annual d18O cycles were preserved and could be counted visually in the uppermost parts of the cores, but deeper layers were affected by post-depositional smoothing. A pronounced d18O minimum was found near the bottom of the three cores. We consider candidates for this d18O signal to be a valuable reference horizon since it is also seen elsewhere in Nordaustlandet. We attribute it to isotopically depleted snow precipitation, which NCEP/NCAR reanalysis shows was unusual for Vestfonna, and came from northerly air during the cold winter of 1994/95. Finding the 1994/95 time marker allows establishment of a precise depth/age scale for the three cores. The derived annual accumulation rates indirectly fill a geographical gap in mass balance measurements and thus provide information on spatial and temporal variability of precipitation over the glacier for the period spanned by the cores (19922009). Comparing records at the two locations also reveals that the snow net accumulation at the easternmost part of Vestfonna was only half of that in the western part over the last 17 years.

  • 2. Beylich, A A
    et al.
    Gintz, D
    Effects of high-magnitude/low-frequency fluvial events generated by intense snowmelt or heavy rainfall in arctic periglacial environments in northern Swedish Lapland and northern Siberia2004Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 86A, nr 1, s. 11-29Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the Latnjavagge drainage basin (68degrees21’N, 18degrees29’E), an arctic-oceanic periglacial environment in northernmost Swedish Lapland, the fluvial sediment transport and the characteristics and importance of high-magnitude/low-frequency fluvial events generated by intense snowmelt or heavy rainfall have been investigated and compared with snowmelt- and rainfall-induced discharge peaks in the Levinson-Lessing Lake basin (Krasnaya river system) on the Taimyr Peninsula, an arctic periglacial environment in northern Siberia (74degrees32’N, 98degrees35’E). In Latnjavagge (9 km(2)) the intensity of fluvial sediment transport is very low. Most of the total annual sediment load is transported in a few days during snowmelt generated runoff peaks. Due to the continuous and very stable vegetation covering most areas below 1300 m a.s.l. in the Latnjavagge catchment, larger rainfall events are of limited importance for sediment transport in this environment. Compared to that, in the c. 40 times larger Krasnaya river system rainfall-generated runoff peaks cause significant sediment transport. The main sediment sources in the Latnjavagge drainage basin are permanent ice patches, channel debris pavements mobilized during peak discharges and exposing fines, and material mobilized by slush-flows. In the Krasnaya river system river bank erosion is the main sediment source. In both periglacial environments more than 90% of the annual sediment yield is transported during runoff peaks. The results from both arctic periglacial environments underline the high importance of high-magnitude/low-frequency fluvial events for the total fluvial sediment budgets of periglacial fluvial systems. Restricted sediment availability is in both arctic environments the major controlling factor for this behaviour.

  • 3. Beylich, A A
    et al.
    Sandberg, O
    Geomorphic effects of the extreme rainfall event of 20-21 July, 2004 in the Latnjavagge catchment, northern Swedish Lapland2005Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 87A, nr 3, s. 409-419Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mass transfers triggered by a rare rainfall event on 20-21 July, 2004, with 58.4 mm of rain within 24 h and 71.7 mm of rain within 48 It in the Latnjavagge catchment (9 km(2), 950-1440 m a.s.l.; 68 degrees 20 ‘ N 18 degrees 30 ‘ E) in the higher Abisko mountain region (Swedish Lapland), are quantified and analysed in direct comparison with mean annual mass transfers in this drainage basin. In years without rare rainfall events the Latnjavagge catchment is characterized by restricted sediment availability resulting in low mechanical denudation and mass transfers. During the rare rainfall event of 20-21 July, 2004, major stability thresholds on the slope systems (triggering debris flows and slides) and in the channel systems (break-up of channel debris pavements and step-pool systems) in the Latnjavagge catchment were passed and mass transfers by debris flows, slides and fluvial debris transport in creeks and channels were several times higher than the mean annual mass transfers in Latnjavagge. In the calculation of longer-term mass transfers and sediment budgets, rare events like the 20-21 July, 2004 rainfall event have to be considered as essential components. A reliable estimation of the recurrence intervals of such rare events is especially problematic. The general problem of defining an adequate length of process monitoring programmes is pointed out.

  • 4.
    Braun, Matthias
    et al.
    Univ Alaska Fairbanks, Inst Geophys, Fairbanks, AK 99775 USA.;Univ Bonn, Ctr Remote Sensing Land Surfaces, D-53113 Bonn, Germany..
    Pohjola, Veijo A.
    Uppsala Univ, Dept Earth Sci Air Water & Landscape Sci, SE-75236 Uppsala, Sweden..
    Pettersson, Rickard
    Uppsala Univ, Dept Earth Sci Air Water & Landscape Sci, SE-75236 Uppsala, Sweden..
    Moeller, Marco
    Rhein Westfal TH Aachen, Dept Geog, D-52056 Aachen, Germany..
    Finkelnburg, Roman
    Tech Univ Berlin, Dept Ecol, D-12165 Berlin, Germany..
    Falk, Ulrike
    Univ Bonn, Ctr Remote Sensing Land Surfaces, D-53113 Bonn, Germany..
    Scherer, Dieter
    Tech Univ Berlin, Dept Ecol, D-12165 Berlin, Germany..
    Schneider, Christoph
    Rhein Westfal TH Aachen, Dept Geog, D-52056 Aachen, Germany..
    CHANGES OF GLACIER FRONTAL POSITIONS OF VESTFONNA (NORDAUSTLANDET, SVALBARD)2011Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 93A, nr 4, s. 301-310Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Glaciers in Svalbard have shown considerable mass loss in recent years with a reported acceleration in the western and southern parts of the archipelago. However, for the ice cap Vestfonna, in northeastern Svalbard, climatic mass balance modelling has suggested almost balanced conditions over a period of nine years (20002009). A slightly positive geodetic mass balance (19902005) has been reported from a comparison of laser altimetry to older DEMs. A heterogeneous situation has been depicted for the various catchments, and hence changes in glacier extent can reveal additional information of glacier status, in particular when dealing with surge-type glaciers. We analysed a 34-year data record of multi-spectral satellite imagery in order to study changes in glacier frontal positions of the ice cap Vestfonna. A consistent pattern of almost steady retreat of the southern and north-eastern outlet glaciers of the ice cap is observed while Franklinbreen, the only major outlet glacier draining towards the north-west shows re-advance. This is consistent with an observed speed up and potential upcoming surge of this outlet. The glacier retreat on the southern coast also agrees with ICESat elevation change measurements. However, due to the glacier response time no direct relations between frontal retreat and surface mass balance can be drawn from the short observation period. The heterogeneous pattern of changes with on-going dynamic adjustments in some areas make the ice cap Vestfonna an ideal test site for future monitoring activities including novel techniques like differential interferometry from bi-static SAR systems.

  • 5. Gude, Martin
    et al.
    Scherer, Dieter
    Snowmelt and Slush Torrents—Preliminary Report from a Field Campaign in Kärkevagge, Swedish Lappland1995Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 77, nr 4, s. 199-206Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In May and June 1995, the snowmelt period in general and the release conditions of slush torrents in particular were studied within a joint Swiss-German project during a field campaign in Kärkevagge, Swedish Lappland. Measurements and observations comprised all energy balance components and meteorological conditions in the course of the snowmelt period, as well as intra- and subnival meltwater flows and the formation of a saturation zone within the snow cover during the initial period of snowmelt-runoff. In addition, release and movement of a high magnitude—low frequency slush torrent was documented on video and photographs. The results verify that the initiation of slush streams is confined to meltwater accumulation areas in drainage basins. Moreover, it can be demonstrated that both variants of slush streams are released by a hydraulic pressure gradient that is evolving from an inclined water table within the saturated snow cover. This release mechanism allows the initiation of major events without any external triggering. Neither permafrost nor extreme meteorological conditions are prerequisite to slush torrents.

  • 6. Isaksson, E
    et al.
    Divine, D
    Kohler, J
    Martma, T
    Pohjola, V
    Motoyama, H
    Watanabe, O
    Climate oscillations as recorded in Svalbard ice core delta O-18 records between AD 1200 and 19972005Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 87A, nr 1, s. 203-214Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We apply two different time series analytical tools to 8180 records from two Svalbard ice cores. One ice core is from Lomonosovfonna at 1250 m a.s.l. and the other from Austfonna at 750 m a.s.l. These cores are estimated to cover at least the past 800 years and have been dated using a combination of known reference horizons and glacial modelling. Wavelet analysis reveals low frequency oscillations on the 60-120-year scale on the lower elevation site Austfonna while the higher altitude site on Lomonosovfonna does not reveal such variability throughout the record. The second method, Significant Zero Crossing of Derivates (SiZer) does not resolve the low-frequency periodicity seen in the wavelet analysis. The low-frequency variability resolved by the wavelet analysis is similar to what has been found in various climate records including instrumental temperatures and tree-rings, and has been proposed as the most important oscillation for the observed trends in Arctic air temperatures.

  • 7. Lundqvist, Jan
    Deposits from landslides and avalanches triggered by seismic activity in swedish lapland2010Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Geografiska Annaler: Series A, Physical Geography, Vol. 92, nr 3, s. 411-420Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abstract.In the mountain area of Swedish Lapland, landforms with semicircular or horse‐shoe ridges encircling hummocky ground occur. They are interpreted as landslide or avalanche deposits directly upon, from or adjacent to down‐wasting ice. Since they are restricted to the vicinity of fault scarps in the Pärvie fault system the releasing factor is suggested to be displacement of bedrock blocks or related seismic activity.

  • 8. Moscicki, Jerzy
    et al.
    Kotarba, Adam
    Kedzia, Stanislaw
    Glacial erosion in the Abisko Mountains: Karkevagge and Vassivagge, Northern Sweden2006Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 88A, nr 2, s. 151-163Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper discusses direct current resistivity soundings and geomorphological studies of Quaternary deposits in two glacial troughs in the Abisko Mountains of northern Sweden. The subject of the fieldwork is the depth of Pleistocene glacial erosion. Studies were carried out in 1998 and 2003 in the Karkevagge and Vassivagge. The estimated thickness of Quaternary deposits and bedrock properties are discussed in the broader context of glacial erosion studies in the Abisko area. Geophysical and geomorphological studies suggest that the depth of glacial erosion was highly differentiated from -190 m in the Tornetrask basin to the metric overall erosion on the upland plateau. In medium-sized valleys several kilometres long, erosion depth measures 30-50 m. Present-day stream channel patterns reveal a strong relation to the bedrock configuration in valley floors.

  • 9. Pettersson, R.
    et al.
    Christoffersen, P.
    Dowdeswell, J. A.
    Pohjola, V. A.
    Hubbard, A.
    Strozzi, T.
    ICE THICKNESS AND BASAL CONDITIONS OF VESTFONNA ICE CAP, EASTERN SVALBARD2011Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 93AArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We combined ground-based pulsed radar data collected in 20082009 with airborne radio-echo sounding data acquired in 1983 and 1986 over Vestfonna ice cap, Svalbard. The airborne dataset mainly covers the fast-flowing outlet glaciers and the marginal zone, while the ground-based data explicitly cover the interior part of the ice cap. The data presented here are thus the first complete estimate of bed topography and ice thickness. The subglacial landscape undulates with elevations between -160 and +410 m above sea level. The mean ice thickness is 186 m and the total ice area and volume are 2402 km2 and 442 +/- 0.6 km3, respectively. This is a much smaller volume than those derived from empirical volume-area scaling relationships currently used to estimate regional-to-global glacier volumes. This difference may depend on local conditions for Vestfonna and emphasizes the need to include more volume observations in the derivations of volume-area scaling parameters. We also derive basal reflectivity as a proxy for thermal conditions at the bed. Basal reflectivity values suggest that fast-flowing outlet glaciers are underlain by temperate conditions. The geometric boundaries and basal conditions for Vestfonna will be critical additions to the development of numerical models of the ice cap and to the estimation of more accurate area-volume scaling parameters.

  • 10. Pohjola, V. A.
    et al.
    Christoffersen, P.
    Kolondra, L.
    Moore, J. C.
    Pettersson, R.
    Schafer, M.
    Strozzi, T.
    Reijmer, C. H.
    SPATIAL DISTRIBUTION AND CHANGE IN THE SURFACE ICE-VELOCITY FIELD OF VESTFONNA ICE CAP, NORDAUSTLANDET, SVALBARD, 1995-2010 USING GEODETIC AND SATELLITE INTERFEROMETRY DATA2011Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 93AArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During 2007 we launched a geodetic campaign on the Svalbard ice cap Vestfonna in order to estimate the velocity field of the ice cap. This was done within the frame of the IPY project KINNVIKA. We present here the velocity measurements derived from our campaigns 20072010 and compare the geodetic measurements against InSAR velocity fields from satellite platforms from 1995/96 and 2008. We find the spatial distribution of ice speeds from the InSAR is in good agreement within the uncertainty limits with our geodetic measurements. We observe no clear indication of seasonal ice speed differences, but we find a speed-up of the outlet glacier Franklinbreen between the InSAR campaigns, and speculate the outlet is having a surge phase.

  • 11.
    Pohjola, Veijo A.
    et al.
    Uppsala Univ, Dept Earth Sci, S-75236 Uppsala, Sweden.;Uppsala Univ, Dept Earth Sci Air Water & Landscape Sci, S-75236 Uppsala, Sweden..
    Kankaanpaa, Paula
    Univ Lapland, Arctic Ctr, FI-96101 Rovaniemi, Finland..
    Moore, John C.
    Univ Lapland, Arctic Ctr, FI-96101 Rovaniemi, Finland.;Beijing Normal Univ, Coll Global Change & Earth Syst Sci, Beijing 100875, Peoples R China.;Uppsala Univ, Dept Earth Sci Air Water & Landscape Sci, S-75236 Uppsala, Sweden..
    Pastusiak, Tadeusz
    Gdynia Maritime Univ, PL-81345 Gdynia, Poland..
    PREFACE: THE INTERNATIONAL POLAR YEAR PROJECT KINNVIKA'- ARCTIC WARMING AND IMPACT RESEARCH AT 80 degrees N2011Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 93A, nr 4, s. 201-208Artikkel i tidsskrift (Annet vitenskapelig)
  • 12. Pohjola, Veijo
    et al.
    Cole-Dai, Jiang
    Rosqvist, Gunhild
    Stroeven, Arjen
    Thompson, Lonnie
    Potential to recover paleoclimatic data in temperate ice cores: an example from the small ice cap Riukojietna, Northern Scandinavia2005Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 87, nr 1, s. 259-270Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have studied a 33.7 m deep ice core from a small polythermal Scandinavian ice cap to determine whether it is possible to recover pre-20th century climatic information from the glacier. Ice structural studies show a significant change from clear ice above 11 m depth (superimposed ice indicating refreezing) to bubbly ice below 11 m depth, indicating this is the transition between Little Ice Age (LIA) and 20th century ice. Calculations with a Nye-age model, along with a mass balance reconstruction, show that this structural boundary likely formed in the last part of the LIA, which in this region ended about 1910. The ice below this boundary was sampled and analyzed for stable isotopic composition and ionic content, which both show significant variations with depth. The stable isotope record likely contains cycles of annual duration during the LIA. The chemistry in the ice core indicates that the information is useful, and can be used to interpret climatic and environmental variables during the LIA. A comparison of Riukojietna ion chemistry and oxygen isotope records to similar records from other glaciers in this region reveals a clear continental – maritime gradient. Changes in this gradient with time may be possible to resolve using such ice core records. Results from this study demonstrate that ice cores from glaciers in this climatic environment can be useful in revealing environmental conditions from climatically colder periods and yield pre-industrial benchmark values for chemical loading and oxygen isotopes, but that hiatuses complicate the depth-age relationship.

  • 13. Ridefelt, Hanna
    et al.
    Åkerman, Jonas
    Beylich, Achim A
    Boelhouwers, Jan
    Kolstrup, Else
    Nyberg, Rolf
    56 years of solifluction measurements in the abisko mountains, northern sweden – analysis of temporal and spatial variations of slow soil surface movement AU - Ridefelt, Hanna2009Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 91, nr 3, s. 215-232Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abstract.Solifluction movement rates from 1952 to 2008 for the Abisko region, northern Sweden, have been compiled and analysed through correlation tests and multiple regression. The temporal analysis is based on two datasets (Lobe11 & gridAB and Line B) from Kärkevagge. The dataset Lobe11 & gridAB show a strong correlation between movement rates and mean annual air temperature (MAAT) and MAAT is also identified as one of the significant contributing parameters in the multiple regression model. No significant correlations were found for the Line B dataset. The spatial analysis indicates generally higher movement rates in the western part of the region and at lower altitudes mainly between 700 and 900 m a.s.l., but the spatial variability is high. To reduce the influence of the temporal variation the data for the correlation tests of the spatial variations were divided into two parts: 1957 to 1980 and 1981 to 2008. The correlation analysis of the dataset 1957 to 1980 shows a significant negative correlation between annual average movement rates and permafrost probability and altitude. The dataset 1981 to 2008 shows a positive correlation between movement rates and wetness index. It is concluded that movement rates may increase with higher MAAT in the western part of the region (Kärkevagge), the spatial variability of movement rates within the region is very high and that altitude (and/or permafrost) together with wetness index are the main controls on the regional spatial variation. The study highlights the limitations in establishing statistical relationships between movement rates and climate using data from different field empirical studies.

  • 14. Vogel, Hendrik
    et al.
    Wagner, Bernd
    Rosén, Peter
    Lake floor morphology and sediment architecture of lake torneträsk, northern sweden2013Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 95, nr 2, s. 159-170Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    AbstractHere we present datasets from a hydroacoustic survey in uly 2011 at Lake orneträsk, northern weden. Our hydroacoustic data exhibit lake floor morphologies formed by glacial erosion and accumulation processes, insights into lacustrine sediment accumulation since the beginning of deglaciation, and information on seismic activity along the Pärvie Fault. Features of glacial scouring with a high?energy relief, steep slopes, and relative reliefs of more than 50 m are observed in the large ?basin. The remainder of the lacustrine subsurface appears to host a broad variety of well preserved formations from glacial accumulation related to the last retreat of the Fennoscandian ice sheet. Deposition of glaciolacustrine and lacustrine sediments is focused in areas situated in proximity to major inlets. Sediment accumulation in distal areas of the lake seldom exceeds 2 m or is not observable. We assume that lack of sediment deposition in the lake is a result of different factors, including low rates of erosion in the catchment, a previously high lake level leading to deposition of sediments in higher elevated paleodeltas, tributaries carrying low suspension loads as a result of sedimentation in upstream lakes, and an overall low productivity in the lake. A clear off?shore trace of the Pärvie Fault could not be detected from our hydroacoustic data. However, an absence of sediment disturbance in close proximity to the presumed fault trace implies minimal seismic activity since deposition of the glaciolacustrine and lacustrine sediments.

  • 15. WILLIAMS, CHRISTOPHER N.
    et al.
    CARRIVICK, JONATHAN L.
    EVANS, ANDREW J.
    RIPPIN, DAVID M.
    QUANTIFYING UNCERTAINTY IN USING MULTIPLE DATASETS TO DETERMINE SPATIOTEMPORAL ICE MASS LOSS OVER 101 YEARS AT KÅRSAGLACIÄREN, SUB2016Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 98, nr 1, s. 61-79Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Glacier mass balance and mass balance gradient are fundamentally affected by changes in glacier 3D geometry. Few studies have quantified changing mountain glacier 3D geometry, not least because of a dearth of suitable spatiotemporally distributed topographical information. Additionally, there can be significant uncertainty in georeferencing of historical data and subsequent calculations of the difference between successive surveys. This study presents multiple 3D glacier reconstructions and the associated mass balance response of Kårsaglaciären, which is a 0.89 ± 0.01 km2 mountain glacier in sub

  • 16. Yang, Zhenlin
    et al.
    Hanna, Edward
    Callaghan, Terry V.
    Modelling surface‐air‐temperature variation over complex terrain around abisko, swedish lapland: uncertainties of measurements and models at different scales2011Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Geografiska Annaler: Series A, Physical Geography, Vol. 93, nr 2, s. 89-112Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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 ∼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 Torneträsk, 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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