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Estimation of urban sensible heat flux using a dense wireless network of observations 总被引:1,自引:0,他引:1
Daniel F. Nadeau W. Brutsaert M. B. Parlange E. Bou-Zeid G. Barrenetxea O. Couach M.-O. Boldi J. S. Selker M. Vetterli 《Environmental Fluid Mechanics》2009,9(6):635-653
The determination of the sensible heat flux over urban terrain is challenging due to irregular surface geometry and surface
types. To address this, in 2006–07, a major field campaign (LUCE) took place at the école Polytechnique Fédérale de Lausanne
campus, a moderately occupied urban site. A distributed network of 92 wireless weather stations was combined with routine
atmospheric profiling, offering high temporal and spatial resolution meteorological measurements. The objective of this study
is to estimate the sensible heat flux over the built environment under convective conditions. Calculations were based on Monin–Obukhov
similarity for temperature in the surface layer. The results illustrate a good agreement between the sensible heat flux inferred
from the thermal roughness length approach and independent calibrated measurements from a scintillometer located inside the
urban canopy. It also shows that using only one well-selected station can provide a good estimate of the sensible heat flux
over the campus for convective conditions. Overall, this study illustrates how an extensive network of meteorological measurements
can be a useful tool to estimate the sensible heat flux in complex urban environments. 相似文献
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Gasser MO Chantigny MH Angers DA Bittman S Buckley KE Rochette P Massé D 《Journal of environmental quality》2012,41(4):1290-1300
Physical, chemical, or biological treatment of animal liquid manure generally produces a dry-matter rich fraction (DMF) that contains most of the initial phosphorus (P). Our objective was to assess the solubility and plant availability of P from various DMFs as a function of soil P status. Eight different DMFs were obtained from liquid swine (LSM) and dairy cattle (LDC) manures treated by natural decantation, anaerobic digestion, chemical flocculation, composting, or mechanical separation. The DMFs were compared with mineral P fertilizer in a pot experiment with oat ( L.) grown in four soils with varied P-fixing capacities and P saturation levels. The DMFs were added at a rate of 50 mg P kg soil and incubated 14 d before seeding. Soil water-extractable P (P) at all water:soil extraction ratios (2:1, 20:1, and 200:1) was slightly higher when DMFs were derived from LDC rather than LSM. Soil P at the 2:1 ratio was lower with anaerobically digested LSM. At the 2:1 extraction ratio, DMF P was less soluble than mineral P as P saturation in soils increased. In soils with a lower P-fixing capacity, DMF P appeared less water soluble than mineral P under 20:1 and 200:1 extraction ratios. After 72 d of plant growth, DMFs produced yields comparable to mineral P fertilizer. Although the plant availability of P from DMFs was comparable to mineral P fertilizer, P from DMFs could be less vulnerable to leaching or runoff losses in soils with a high P saturation level or low P-fixing capacity. 相似文献
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