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Net radiation balance for two forested slopes on opposite sides

Author:
  • Thomas Holst
  • Jutta Holst
  • Helmut Mayer
Publishing year: 2005
Language: English
Pages: 275-284
Publication/Series: International Journal of Biometeorology
Volume: 49
Document type: Journal article
Publisher: Springer

Abstract english

Measurements of the net radiation balance of two forested sites on the opposite slopes of a valley in south-western Germany, made over 3 years, are presented in this study. Radiation sensors were mounted horizontally on two measurement towers above two beech stands. The direct part of the measured short-wave incoming radiation was adjusted according to the slope’s angle to convert horizontally measured radiation data into surface-parallel radiation fluxes. During periods when contemporaneous measurements of slope-parallel and horizontal radiation fluxes were available, the calculation of surface-parallel radiation fluxes from the horizontally recorded net radiation components were compared with measured values. The net radiative fluxes parallel to the slopes were calculated for a period of 36 months and analysed. Results show that the different aspects of both sites cause significant differences of the net radiation balance. In June, when the elevation of the sun is highest, incoming solar radiation K¯ received on the NE-slope was 9% lower than K¯ received on the SW-slope. During the winter months, the differences were much greater and incoming solar radiation to the NE-slope was 50% of that to the SW-slope. Due to the differing solar irradiance, net radiation fluxes were significantly higher on the SW-slope than on the NE-slope. For long-wave radiation only small differences between both slopes could be found. Since radiative fluxes determine the energy balance and hence the microclimate and water balance of a forest stand, these differences in the net radiation balance between the slopes are important for the vegetation.

Keywords

  • Physical Geography
  • Net radiation balance · Slope · Aspect · Surface-parallel fluxes · Solar radiation

Other

Published
  • ISSN: 1432-1254
E-mail: jutta [dot] holst [at] nateko [dot] lu [dot] se

Researcher

Dept of Physical Geography and Ecosystem Science

+46 46 222 40 39

+46 72 254 72 00

445

16

Research secretary

ICOS Sweden

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Researcher

ICOS Sweden

+46 46 222 40 39

+46 72 254 72 00

444a

Sölvegatan 12, Lund

16

Department of Physical Geography and Ecosystem Science
Lund University
Sölvegatan 12
S-223 62 Lund
Sweden

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