Atmospheric Boundary Layer Dynamics in Regions of Complex Terrain

Atmospheric Boundary Layer Dynamics in Regions of Complex Terrain PDF Author: Eric Richard Pardyjak
Publisher:
ISBN:
Category : Atmospheric circulation
Languages : en
Pages : 410

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Atmospheric Boundary Layer Dynamics in Regions of Complex Terrain

Atmospheric Boundary Layer Dynamics in Regions of Complex Terrain PDF Author: Eric Richard Pardyjak
Publisher:
ISBN:
Category : Atmospheric circulation
Languages : en
Pages : 410

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A Numerical Study of Atmospheric Boundary Layer Dynamics Over Complex Terrain

A Numerical Study of Atmospheric Boundary Layer Dynamics Over Complex Terrain PDF Author: Nash'at Naveed Ahmad
Publisher:
ISBN:
Category : Atmospheric turbulence
Languages : en
Pages : 198

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The Atmospheric Boundary Layer

The Atmospheric Boundary Layer PDF Author: J. R. Garratt
Publisher: Cambridge University Press
ISBN: 9780521467452
Category : Mathematics
Languages : en
Pages : 340

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Book Description
The book gives a comprehensive and lucid account of the science of the atmospheric boundary layer (ABL). There is an emphasis on the application of the ABL to numerical modelling of the climate. The book comprises nine chapters, several appendices (data tables, information sources, physical constants) and an extensive reference list. Chapter 1 serves as an introduction, with chapters 2 and 3 dealing with the development of mean and turbulence equations, and the many scaling laws and theories that are the cornerstone of any serious ABL treatment. Modelling of the ABL is crucially dependent for its realism on the surface boundary conditions, and chapters 4 and 5 deal with aerodynamic and energy considerations, with attention to both dry and wet land surfaces and sea. The structure of the clear-sky, thermally stratified ABL is treated in chapter 6, including the convective and stable cases over homogeneous land, the marine ABL and the internal boundary layer at the coastline. Chapter 7 then extends the discussion to the cloudy ABL. This is seen as particularly relevant, since the extensive stratocumulus regions over the subtropical oceans and stratus regions over the Arctic are now identified as key players in the climate system. Finally, chapters 8 and 9 bring much of the book's material together in a discussion of appropriate ABL and surface parameterization schemes in general circulation models of the atmosphere that are being used for climate simulation.

Atmospheric Boundary Layer Dynamics of Transitional Flows Over Complex Terrain

Atmospheric Boundary Layer Dynamics of Transitional Flows Over Complex Terrain PDF Author: Daniel Nadeau
Publisher:
ISBN:
Category :
Languages : en
Pages : 99

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Atmospheric Processes over Complex Terrain

Atmospheric Processes over Complex Terrain PDF Author: William Blumen
Publisher: Springer
ISBN: 1935704257
Category : Science
Languages : en
Pages : 331

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Book Description
The objectives of the American Meteorological Society are "the development and dissemination of knowledge of meteorology in all its phases and applications, and the advancement of its professional ideals." The organization of the Society took place in affiliation with the American Association for the Advancement of Science at Saint Louis, Missouri, December 29, 1919, and its incorporation, at Washington, D. C., January 21, 1920. The work of the Society is carried on by the Bulletin, the Journal, and Meteorological Monographs, by papers and discussions at meetings of the Society, through the offices of the Secretary and the Executive Secretary, and by correspondence. All of the Americas are represented in the membership of the Society as well as many foreign countries.

The Neutral Atmospheric Boundary Layer Over Complex Terrain

The Neutral Atmospheric Boundary Layer Over Complex Terrain PDF Author: William Peter Kustas
Publisher:
ISBN:
Category : Boundary layer (Meteorology)
Languages : en
Pages : 336

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Modeling the atmospheric boundary layer in stably stratified conditions and over complex terrain areas

Modeling the atmospheric boundary layer in stably stratified conditions and over complex terrain areas PDF Author: Mireia Udina Sistach
Publisher:
ISBN:
Category :
Languages : ca
Pages : 176

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Book Description
The atmospheric boundary layer in stably-stratified conditions and over non-homogeneous terrain becomes a complex system with many interactions of physical processes occurring in a wide range of different spatial and temporal scales. During clear sky night-time or in any stably-stratified conditions intermittent turbulent events and gravity waves are usually present in the stable boundary layer (SBL), which can substantially modify the flow structure. In addition, the circulations in stable flows can be strongly driven by the underlying and surrounding topography, generating katabatic winds, density currents and low level jets, which in turn, trigger gravity waves and turbulence. This thesis aims to contribute to a better comprehension of some of the processes and phenomena occurring in the SBL and over complex terrain areas. In order to understand and quantify the unknown atmospheric processes one can distinguish three different procedures that are very well connected: theoretical descriptions, experimental campaigns and numerical modeling. The numerical models allow us to further understand the experimental data, to test the theoretical relationships or to simulate processes which are very difficult to measure. Principally, in this thesis we have used numerical models to deal with the uncertainties that arise in stably-stratified flows and over heterogeneous terrain and to explore the model capabilities and limitations to resolve them. These numerical weather prediction models (NWP) contain the primitive equations of the atmosphere to describe and forecast the flow motions and properties. In this thesis we have employed one of the worldwide known NWP model, the Weather Research and Forecasting (WRF) model, using two different approaches: the mesoscale approximation and the large eddy simulation (LES). While the mesoscale methodology has allowed us to investigate the flow circulation patterns in a wide range of scales, the LES approximation has enabled us to explicitly resolve the turbulence and describe its structure. In this thesis each methodology has been applied to investigate these different purposes. Using the WRF model with the mesoscale approach we have determined the origin of a density current that generated internal gravity waves over the "Centro de Investigaciones de la Baja Atmosfera"(CIBA) site. We have seen that the long distance mesoscale sea-breeze circulation and the night-time katabatic flows originated at the surrounding complex topography were the origin of the density current which generated displacement in the air parcels and periodic oscillations. In this thesis we have also investigated the vertical turbulence structure using the LES approximation of the WRF model. As a previous step, we have first validated the WRF-LES model in the SBL with a reference case by a comparison of the first and second order moments profiles. Using different wind speed initial conditions we reproduce neutrally and stably stratified flows. However, different from the reality, stably stratified flows are strongly coupled with the surface and turbulence is always maintained. We have shown how the turbulence intensity increases sharply with the wind speed at each height above ground but the rate of increase (slope) is not maintained, as we would expect. It seems that the the top domain potential temperature inversion affects the flow turbulence structure over the whole domain. Finally, we have studied topographically generated gravity waves over the Pyrenees and specifically simulated a trapped lee wave event using the mesoscale approximation with WRF. We have seen that the model is able to reproduce the gravity waves at the lee side of the mountain range with periodic oscillations in all magnitudes. We have seen that 1-km horizontal resolution is necessary to capture the wave field. We have also showed that upstream conditions have to be well represented to capture the adequate wave characteristics.

The Atmosphere over Mountainous Regions

The Atmosphere over Mountainous Regions PDF Author: Miguel A. C. Teixeira
Publisher: Frontiers Media SA
ISBN: 2889450163
Category :
Languages : en
Pages : 162

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Book Description
Mountainous regions occupy a significant fraction of the Earth's continents and are characterized by specific meteorological phenomena operating on a wide range of scales. Being a home to large human populations, the impact of mountains on weather and hydrology has significant practical consequences. Mountains modulate the climate and create micro-climates, induce different types of thermally and dynamically driven circulations, generate atmospheric waves of various scales (known as mountain waves), and affect the boundary layer characteristics and the dispersion of pollutants. At the local scale, strong downslope winds linked with mountain waves (such as the Foehn and Bora) can cause severe damage. Mountain wave breaking in the high atmosphere is a source of Clear Air Turbulence, and lee wave rotors are a major near-surface aviation hazard. Mountains also act to block strongly stratified air layers, leading to the formation of valley cold air-pools (with implications for road safety, pollution, crop damage, etc.) and gap flows. Presently, neither the fine-scale structure of orographic precipitation nor the initiation of deep convection by mountainous terrain can be resolved adequately by regional-to global-scale models, requiring appropriate downscaling or parameterization. Additionally, the shortest mountain waves need to be parameterized in global weather and climate prediction models, because they exert a drag on the atmosphere. This drag not only decelerates the global atmospheric circulation, but also affects temperatures in the polar stratosphere, which control ozone depletion. It is likely that both mountain wave drag and orographic precipitation lead to non-trivial feedbacks in climate change scenarios. Measurement campaigns such as MAP, T-REX, Materhorn, COLPEX and i-Box provided a wealth of mountain meteorology field data, which is only starting to be explored. Recent advances in computing power allow numerical simulations of unprecedented resolution, e.g. LES modelling of rotors, mountain wave turbulence, and boundary layers in mountainous regions. This will lead to important advances in understanding these phenomena, as well as mixing and pollutant dispersion over complex terrain, or the onset and breakdown of cold air pools. On the other hand, recent analyses of global circulation biases point towards missing drag, especially in the southern hemisphere, which may be due to processes currently neglected in parameterizations. A better understanding of flow over orography is also crucial for a better management of wind power and a more effective use of data assimilation over complex terrain. This Research Topic includes contributions that aim to shed light on a number of these issues, using theory, numerical modelling, field measurements, and laboratory experiments.

Modelling Of Atmospheric Flow Fields

Modelling Of Atmospheric Flow Fields PDF Author: Demetri P Lalas
Publisher: World Scientific
ISBN: 9814602833
Category :
Languages : en
Pages : 768

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Book Description
This volume is a collection of lectures given at the two colloquia on atmospheric flows over complex terrain with applications to wind energy and air pollution, organized and sponsored by ICTP in Trieste, Italy. The colloquia were the result of the recognition of the importance of renewable energy sources, an important aspect which grows yearly as the environmental problems become more pronounced and their effects more direct and intense, while at the same time, the wise management of the Earth's evidently limited resources becomes imperative.It is divided into two main parts. The first, which comprises Chaps. 1 to 4, presents the structure of the atmospheric boundary layer with emphasis in the region adjacent to the ground. The second, Chaps. 5 to 10, discusses methods for the numerical computation of the wind field on an arbitrary terrain. The unique feature of this book is that it does not stop at the theoretical exposition of the analytical and numerical techniques but includes a number of codes, in a diskette, where the mechanisms and techniques presented in the main part are implemented and can be run by the reader. Some of the codes are of instructional value while others can be utilized for simple operational work.Some of the lecturers are: D N Asimakopoulos, C I Aspliden, V R Barros, A K Blackadar, G A Dalu, A de Baas, D Etling, G Furlan, D P Lalas, P J Mason, C F Ratto and F B Smith.

Atmospheric Boundary Layer Modeling in Complex Terrain

Atmospheric Boundary Layer Modeling in Complex Terrain PDF Author: Yu Song
Publisher:
ISBN:
Category : Atmospheric circulation
Languages : en
Pages : 264

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