Turbulence and Dispersion in the Planetary Boundary Layer

verfasst von: Francesco Tampieri

Verlag: Springer International Publishing

Buchreihe : Physics of Earth and Space Environments

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik" , Springer Professional "Wirtschaft"

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Über dieses Buch

This book offers a comprehensive review of our current understanding of the planetary boundary layer, particularly the turbulent exchanges of momentum, heat and passive scalars between the surface of the Earth and the atmosphere. It presents and discusses the observations and the theory of the turbulent boundary layer, both for homogeneous and more realistic heterogeneous surface conditions, as well as the dispersion of tracers. Lastly it addresses the main problems arising due to turbulence in weather, climate and atmospheric composition numerical models. Written for postgraduate and advanced undergraduate-level students and atmospheric researchers, it is also of interest to anyone wanting to understand the findings and obtain an update on problems that have yet to be solved.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract

In the Introduction the planetary boundary layer (PBL) is described in general, as the part of the atmosphere where turbulence acts driving exchange processes and dispersion. Attention is paid to field and laboratory measurements, as well as to the use of numerical experiments as a further tool for knowledge.

Francesco Tampieri

Chapter 2. A Summary of Mathematics and Physics for PBL

Abstract

This chapter is a summary of the mathematics and physics needed for understanding and modelling the PBL and the dispersion. Definition and equations are necessary for setting the nomenclature and the symbols. Probability density functions, correlation functions and spectra are introduced. References will be given for the derivations of the Navier-Stokes and thermodynamics equations as well as the equations for the averaged quantities. The inertial subrange theory and the eddy diffusivity concept will be presented here, with proper references for further readings.

Francesco Tampieri

Chapter 3. The Basic Paradigm: Horizontal Homogeneity Over Flat Terrain

Abstract

The idealized conditions of horizontal homogeneity allow to develop the basic theory for the PBL. In this chapter we focus on what happens when the PBL processes depend only on the vertical coordinate and on the time. The similarity theory and the data (mainly from the field) lead to the formulation of parameterizations which are the essential background for the understanding of the observations and for the numerical modelling.

Francesco Tampieri

Chapter 4. Horizontal Heterogeneities

Abstract

In this Chapter we address a number of issues that contradict the fundamental requirements of the basic paradigm presented in Chap. 3 In this way we tackle the question, how to cope with the real world features. Two broad lines of approach are presented: the explicit treatment of the space-dependent problem, and the averaging over the typical variation scale. Changes in the surface features and topographic effects are examples for the first approach. Flow into a canopy (both a forest and a city) and parameterizations of sub-grid scale (unresolved) heterogeneities are examples for the second approach.

Francesco Tampieri

Chapter 5. Turbulent Dispersion

Abstract

This chapter deals with the problem of transport of tracers from a source. At first a few general results are discussed, highlighting the peculiar features of the turbulent dispersion, its similitudes to molecular diffusion and its differences. The statistical description allows to recognize the velocity-uncorrelated approach (the diffusion approach, valid for times larger than the characteristic time scale of the turbulent velocities) and the acceleration-uncorrelated approach (valid also for times shorter than the velocity time scale), recasting on formal bases the popular classification of Eulerian and Lagrangian dispersion models. The Lagrangian Stochastic Model (LSM) approach is discussed in detail, being the basis for many practical modeling tools, based on the use both of the observations and of the numerical simulations. Some aspects related to the problem of the fluctuations in the concentration of tracers are introduced. The inertial particle dispersion is treated shortly.

Francesco Tampieri

Chapter 6. Numerical Modeling of Turbulence for PBL Flows

Abstract

Some general ideas about the turbulence representation in numerical models of PBL flows are presented. The parameterizations (closures) are discussed with reference to RANS and LES models. Complex flows can be described only via numerical simulations: some broad fields of application are exemplified.

Francesco Tampieri

Backmatter

Titel: Turbulence and Dispersion in the Planetary Boundary Layer
verfasst von: Francesco Tampieri
Verlag: Springer International Publishing
Electronic ISBN: 978-3-319-43604-3
Print ISBN: 978-3-319-43602-9
DOI: https://doi.org/10.1007/978-3-319-43604-3