نتایج جستجو برای: atmospheric boundary layer

تعداد نتایج: 489371  

2013
K. Korhonen

Introduction Conclusions References

2006
P. S. Anderson

1-D profiles and time series from an idealised atmospheric boundary layer model are presented, which show agreement with boundary layer measurements of polar NOx. Diffusion models are increasingly being used as the framework for studying tropospheric air chemistry dynamics. Models based on standard boundary layer diffusivity profiles have an intrinsic behaviour that is not necessarily intuitive...

Journal: :Applied optics 2013
Shi Kuang Michael J Newchurch John Burris Xiong Liu

Ground-based lidars are suitable for long-term ozone monitoring as a complement to satellite and ozonesonde measurements. However, current ground-based lidars are unable to consistently measure ozone below 500 m above ground level (AGL) due to both engineering issues and high retrieval sensitivity to various measurement errors. In this paper, we present our instrument design, retrieval techniqu...

2002
Helen N Webster David J Thomson Alison L Redington Derrick B Ryall

INTRODUCTION Emissions from power station stacks and many other anthropogenic sources have substantial vertical velocities and are often hot compared with the surrounding ambient air. These momentum and buoyancy effects cause the emitted plume to rise, increasing the effective source height and, in the main, reducing maximum ground level concentrations. It follows that an accurate prediction of...

2009
T. TRAVOUILLON L. JOLISSAINT J. W. V. STOREY

The unique atmospheric conditions present at sites such as Dome C on the Antarctic plateau are very favorable for high spatial resolution astronomy. At Dome C, the majority of the optical turbulence is confined to a 30 to 40 m thick stable boundary layer that results from the strong temperature inversion created by the heat exchange between the air and the ice-covered ground. To fully realize t...

2013
Laurent Perret Eric Savory

Street canyon flow regimes are classified using the time-averaged mean flow. The present paper discusses recent work on the dynamics of street canyon flows (important for pollutant transport) and the interaction with the shear layer and atmospheric boundary layer above, with a view to classifying the different regimes in terms of the unsteady characteristics of the flow for different types of c...

2012
Nicholas Hutchins Kapil Chauhan Ivan Marusic Joseph Klewicki

A collaborative experimental effort employing the minimally perturbed atmospheric surface-layer flowover the salt playa ofwesternUtah has enabled us tomap coherence in turbulent boundary layers at very high Reynolds numbers, Reτ ∼ O(106). It is found that the large-scale coherence noted in the logarithmic region of laboratory-scale boundary layers are also present in the very high Reynolds numb...

2012
PLANETARYBOUNDARY LAYER PETER P. SULLIVAN

In this work, we study the characteristics of a stably stratified atmospheric boundary layer using large-eddy simulation (LES). In order to simulate the stable planetary boundary layer, we developed a modified version of the two-part subgrid-scale model of Sullivan et al. This improved version of the model is used to simulate a highly cooled yet fairly windy stable boundary layer with a surface...

2010
Eric D. Skyllingstad Roger M. Samelson

The primary scientific objectives of the proposed research are to use a coupled atmosphere--ocean model to investigate and quantify the interaction between the oceanic and atmospheric boundary layers and its effect on environmental conditions in the coastal zone. The main focus will be on boundary layer interactions under coastal upwelling conditions, in which cold, upwelled ocean surface water...

2005
Weston D C Heuer Ivan Marusic

A new sensor is described for measuring the fluctuating component of the wall-shear stress in the atmospheric surface layer over relatively smooth uniform terrain. The sensor was tested at the Surface Layer Turbulence and Environmental Science Test (SLTEST) site on the western salt flats of Utah, giving the first ever direct measurements of this quantity in an atmospheric-scale flow. The device...

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