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Net radiation balance for two forested slopes on opposite sides

Holst, Thomas LU ; Holst, Jutta LU and Mayer, Helmut (2005) In International Journal of Biometeorology 49. p.275-284
Abstract
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... (More)
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. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Net radiation balance · Slope · Aspect · Surface-parallel fluxes · Solar radiation
in
International Journal of Biometeorology
volume
49
pages
275 - 284
publisher
Springer
external identifiers
  • scopus:18744389827
ISSN
1432-1254
DOI
10.1007/s00484-004-0251-1
language
English
LU publication?
no
id
6cbfac35-ee7d-4b0b-aeb3-807f42731bde (old id 591887)
date added to LUP
2007-12-18 12:51:29
date last changed
2017-01-22 04:17:08
@article{6cbfac35-ee7d-4b0b-aeb3-807f42731bde,
  abstract     = {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.},
  author       = {Holst, Thomas and Holst, Jutta and Mayer, Helmut},
  issn         = {1432-1254},
  keyword      = {Net radiation balance · Slope · Aspect · Surface-parallel fluxes · Solar radiation},
  language     = {eng},
  pages        = {275--284},
  publisher    = {Springer},
  series       = {International Journal of Biometeorology},
  title        = {Net radiation balance for two forested slopes on opposite sides},
  url          = {http://dx.doi.org/10.1007/s00484-004-0251-1},
  volume       = {49},
  year         = {2005},
}