17,724 research outputs found
Using natural means to reduce surface transport noise during propagation outdoors
This paper reviews ways of reducing surface transport noise by natural means. The noise abatement solutions of interest can be easily (visually) incorporated in the landscape or help with greening the (sub)urban environment. They include vegetated surfaces (applied to faces or tops of noise walls and on building façades and roofs ), caged piles of stones (gabions), vegetation belts (tree belts, shrub zones and hedges), earth berms and various ways of exploiting ground-surface-related effects. The ideas presented in this overview have been tested in the laboratory and/or numerically evaluated in order to assess or enhance the noise abatement they could provide. Some in-situ experiments are discussed as well. When well-designed, such natural devices have the potential to abate surface transport noise, possibly by complementing and sometimes improving common (non-green) noise reducing devices or measures. Their applicability strongly depends on the available space reserved for the noise abatement and the receiver position
The International Urban Energy Balance Models Comparison Project: First Results from Phase 1
A large number of urban surface energy balance models now exist with different assumptions about the
important features of the surface and exchange processes that need to be incorporated. To date, no com-
parison of these models has been conducted; in contrast, models for natural surfaces have been compared
extensively as part of the Project for Intercomparison of Land-surface Parameterization Schemes. Here, the
methods and ïŹrst results from an extensive international comparison of 33 models are presented. The aim of
the comparison overall is to understand the complexity required to model energy and water exchanges in
urban areas. The degree of complexity included in the models is outlined and impacts on model performance
are discussed. During the comparison there have been signiïŹcant developments in the models with resulting
improvements in performance (root-mean-square error falling by up to two-thirds). Evaluation is based on a
dataset containing net all-wave radiation, sensible heat, and latent heat ïŹux observations for an industrial area in
Vancouver, British Columbia, Canada. The aim of the comparison is twofold: to identify those modeling ap-
proaches that minimize the errors in the simulated ïŹuxes of the urban energy balance and to determine the
degree of model complexity required for accurate simulations. There is evidence that some classes of models
perform better for individual ïŹuxes but no model performs best or worst for all ïŹuxes. In general, the simpler
models perform as well as the more complex models based on all statistical measures. Generally the schemes
have best overall capability to model net all-wave radiation and least capability to model latent heat ïŹux
White paper â On the use of LiDAR data at AmeriFlux sites
Our aim is to inform the AmeriFlux community on existing and upcoming LiDAR technologies (atmospheric Doppler
or Raman LiDAR often deployed at flux sites are not considered here), how it is currently used at flux sites, and how
we believe it could, in the future, further contribute to the AmeriFlux vision. Heterogeneity in vegetation and ground
properties at various spatial scales is omnipresent at flux sites, and 3D mapping of canopy, understory, and ground
surface can help move the science forward
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