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MODELLING SURFACE-AIR-TEMPERATURE VARIATION OVER COMPLEX TERRAIN AROUND ABISKO, SWEDISH LAPLAND: UNCERTAINTIES OF MEASUREMENTS AND MODELS AT DIFFERENT SCALES

Authors

  • ZHENLIN YANG,

    1. Department of Geography, University of Sheffield, Sheffield, UK
    2. Department of Earth and Ecosystem Sciences, Lund University, Lund, Sweden
    3. Abisko Scientific Research Station, The Royal Swedish Academy of Sciences, Abisko, Sweden
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  • EDWARD HANNA,

    1. Department of Geography, University of Sheffield, Sheffield, UK
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  • TERRY V. CALLAGHAN

    1. Abisko Scientific Research Station, The Royal Swedish Academy of Sciences, Abisko, Sweden
    2. Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
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Abstract

Zhenlin, Y., Hanna, E. and Callaghan, T. V., 2011: Modelling surface-air-temperature variation over complex terrain around Abisko, Swedish Lapland: uncertainties of measurements and models at different scales. Geografiska Annaler: Series A, Physical Geography, 93, 89–112. DOI: 10.1111/j.1468-0459. 2011.00005.x

ABSTRACT

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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