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Excess resistance of bog surfaces in central Sweden

Mölder, Meelis LU and Kellner, E (2002) In Agricultural and Forest Meteorology 112(1). p.23-30
Abstract
Typical bogs in boreal forest zone can be characterized by hummock and hollow micro-topography and sparsely vegetated surfaces, thus, are quite distinct from other types of wetlands. Micrometeorological measurements were carried out in central Sweden at two bogs in different summer seasons. The data analysis aimed at obtaining good estimates for the roughness length z(ou) and the kB(-1) factor. The roughness length for wind speed (z(ou)) was estimated to be 2 cm. A good surface temperature estimate is crucial for kB-1 calculations. The surface temperature of such a heterogeneous surface showed high spatial variability, the differences between its minimum and maximum values reaching 10 K during daytime. However, an infrared thermometer... (More)
Typical bogs in boreal forest zone can be characterized by hummock and hollow micro-topography and sparsely vegetated surfaces, thus, are quite distinct from other types of wetlands. Micrometeorological measurements were carried out in central Sweden at two bogs in different summer seasons. The data analysis aimed at obtaining good estimates for the roughness length z(ou) and the kB(-1) factor. The roughness length for wind speed (z(ou)) was estimated to be 2 cm. A good surface temperature estimate is crucial for kB-1 calculations. The surface temperature of such a heterogeneous surface showed high spatial variability, the differences between its minimum and maximum values reaching 10 K during daytime. However, an infrared thermometer averaging over a circle of a few meters still gave an acceptable result. The kB-1 factor was determined through the roughness sublayer Stanton number and the corresponding drag coefficient and was dependent on the roughness Reynolds number (Re-o). It took the form: kB(-1) = 1.58Re(o)(0.25) - 3.4. Within considerable scatter of data, a constant kB(-1) = 3.2 was also acceptable. This result lies in between the bluff-rough and vegetated surface cases. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Stanton number, turbulent fluxes, surface radiation temperature, roughness length
in
Agricultural and Forest Meteorology
volume
112
issue
1
pages
23 - 30
publisher
Elsevier
external identifiers
  • wos:000177458800002
  • scopus:0037206009
ISSN
1873-2240
DOI
10.1016/S0168-1923(02)00043-6
language
English
LU publication?
yes
id
914c3be1-3bbd-48fc-957d-e9bedbe76287 (old id 331155)
date added to LUP
2007-11-16 16:10:06
date last changed
2017-01-01 07:06:16
@article{914c3be1-3bbd-48fc-957d-e9bedbe76287,
  abstract     = {Typical bogs in boreal forest zone can be characterized by hummock and hollow micro-topography and sparsely vegetated surfaces, thus, are quite distinct from other types of wetlands. Micrometeorological measurements were carried out in central Sweden at two bogs in different summer seasons. The data analysis aimed at obtaining good estimates for the roughness length z(ou) and the kB(-1) factor. The roughness length for wind speed (z(ou)) was estimated to be 2 cm. A good surface temperature estimate is crucial for kB-1 calculations. The surface temperature of such a heterogeneous surface showed high spatial variability, the differences between its minimum and maximum values reaching 10 K during daytime. However, an infrared thermometer averaging over a circle of a few meters still gave an acceptable result. The kB-1 factor was determined through the roughness sublayer Stanton number and the corresponding drag coefficient and was dependent on the roughness Reynolds number (Re-o). It took the form: kB(-1) = 1.58Re(o)(0.25) - 3.4. Within considerable scatter of data, a constant kB(-1) = 3.2 was also acceptable. This result lies in between the bluff-rough and vegetated surface cases.},
  author       = {Mölder, Meelis and Kellner, E},
  issn         = {1873-2240},
  keyword      = {Stanton number,turbulent fluxes,surface radiation temperature,roughness length},
  language     = {eng},
  number       = {1},
  pages        = {23--30},
  publisher    = {Elsevier},
  series       = {Agricultural and Forest Meteorology},
  title        = {Excess resistance of bog surfaces in central Sweden},
  url          = {http://dx.doi.org/10.1016/S0168-1923(02)00043-6},
  volume       = {112},
  year         = {2002},
}